Delaware beaver management plan

[From the U.S. Government Printing Office, www.gpo.gov]

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Delaware Division of Fish and Wildlife
Department of Natural Resources and Environmental Control

September, 1991

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QC d through Federal Grant from the Office of Coastal Zone
ment, NOAA under provision of Section 306 of the Coastal
737 Zone Management Act of 1972 as amended.
.R632
D45
1991

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Delaware Division of Fish and Wildlife
Department of Natural Resources and Environmental Control

September, 1991

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Funded through Federal Grant from the Office of Coastal Zone
Management, NOAA under provision of Section 306 of the Coastal
Zone Management Act of 1972 as amended.

Table of Contents
PG. NO.

Executive Summary . . . . . . . . . . . . . . . . . . V-vii

I. Introduction . . . . . . . . . . . . . . . . . . . . 1

II. General Policy and Plan Purpose . . . . . . . . . . . 1-2

III. Biology and Ecology . . . . . . . . . . . . . . . . . 2-7
1. Description . . . . . . . . . . . . . . . . . . . 2-3
2. Range and Habitat . . . . . . . . . . . . . . . . 3
3. Dens, Lodges, Dams and Other Structures . . . . . 3-4
4. Food Habits . . . . . . . . . . . . . . . . . . . 4-5
5. Wetlands Successional Cycles . . . . . . . . . . 5
6. Reproduction and Development . . . . . . . . . . 5-6
7. Population Structure and Density . . . . . . . . 6
8. Mortality . . . . . . . . . . . . . . . . . . . . 7

IV. Status and Trends of Beaver in Delaware . . . . . . . 7-17
1. Historical Distribution of Beaver in
North America, the mid-Atlantic, and
Delaware . . . . . . . . . . . . . . . . . . . . 7-9
2. Current Status of Beaver in Delaware . . . . . . 9
3. Current Distribution and Population of
Beaver in Delaware . . . . . . . ... . . . . . . 9-15
4. Future Population Growth of Beavers in
Delaware . . . . . . . . . . . . . . . . . . . . 15-16
5. Examples of Beaverdam Wetlands Habitat in
Delaware . . . . . . . . . . . . . . . . . . . . 16-17

V. Environmental and Socioeconomic Benefits of
Beavers and Beaverdam Wetlands . . . . . . . . . . . 17-21
1. Quality Fish and Wildlife Wetlands Habitat . . . 17-19
2. Recreation and Aesthetics . . . . . . . . . . . . 19
3. Flood Control . . . . . . . . . . . * * * * * * * 19
4. Water Quality Effects-Dissolved Nutrients
and Particulate Sediments . . . . . . . . . . . . 19-21
5. Summary of Attributes . . . . . . . . . . . . . . 21

VI. Socioeconomic/Environmental Problems Caused by
Beavers . . . . . . . . . . . . . . . . . . . . . . . 21-22
1. Flooding Problems . . . . . . . . . . . . . . . . 21-22
2. Other Damages to Property . . . . . . . . . . . . 22

VII. Determination if Substantive Beaver-Caused
Socioeconomic Problems are Occurring . . . . . . . . 23-26
1. Types and Locations of Potential Problems and
Factors to Consider and Evaluate . . . . . . . . 23-24
A. Private Lands in Urban or Suburban Areas 23
B. Tax Ditches . . . . . . . . . * - 23-24
C. Public Lands-Conservation or Recr;atii@n*
Areas. . . ' * 24
D. Highways, R;ilw;yL,'Alrp*ort; . . . . 24

E. Private Land in Rural Areas (Non-tax
Ditch) . . . . . . . . . . . . . . . . . . . 24
2. Prioritization of Concerns if Two or More
Types of Problems are Occurring at One Site . . . 24-25
3. Integration of Factors to Make a Decision if
Substantive Problems are Occurring and if
Remedial Action is Warranted . . . . . . . . . . 25-26

VIII. Remedial Response Options if a Substantive Beaver-
Caused Socioeconomic Problem is Occurring . . . . . . 26-38
1. Live-trapping and Transfer of Problem-Beavers. 26-31
A. Identification of Potential Release Sites
for Live-trapped and Transferred Beaver . . . 26-28
B. Potential Release Sites in Delaware . . . . . 28-30
C. Methods of Live-trapping . . . . . . . . . . 30
D. Methods of Transfer . . . . . . . . . . . . . 30-31
E. Potential Need and Procedures for Repro-
ductive Control of Transferred Beavers . . . 31
F. Long-Term Monitoring of Transferred
Beavers . . . . . . . . . . . . . . . . . . . 31
2. Dispatch of Problem-Beavers . . . . . . . * , * * 31-32
3. Regulated Trapping Program Open to the Public. . 32-34
4. Structural Remedies to Resolve Flooding
Problems Caused by Beavers . . . . . . . . . . . 34-36
5. Choosing a Remedial Response for a Substantive
Beaver-Caused Problem . . . . . . . . . . . . . . 36-37
6. Criteria for Evaluating the Environmental
Quality or Importance of Existing Beaverdam
Wetlands . . . . . . . . . . . . . . . . . . . . 37-38

IX. Identification of Types of Action Costs Associated
With Implementing a Beaver Management Plan . . . . . 38

X. Preferred Participation and Responsibilities of
Agencies and Personnel in a Beaver Management Plan 39-42

XI. Listing of Management Options to Manage Beaver-
Abandoned Beaverdam Wetlands . . . . . . . . . . . . 42

XII. Public Education and Beavers . . . . . . . . . . . . 42

XIII. Proposed Immediate Action-Steps to Implement
the Plan . . . . . . . . . . . . . . . . . . . . . . 42-45

XIV. Pertinent References . . . . . . . . . . . . . . . . . 46-47

XV. Appendices (Contents) . . . . . . . . . . . . . . . . 48-109
Delaware Division of Fish and Wildlife
Management Philosophy (Appendix 1) . . . . . . . 49-50
2. Title 7, Chapter 7, Section 701 -- Regulations
and Prohibitions Concerning Game and Fish
(Appendix 2) . . . . . . . . . . . . . . . . . . 51

3. Descriptions of Selected Beaverdam-wetlands
Habitats in Delaware . . . . . 52-55
a. Garrisons Lake (Appendix 3): 52-53
b. Paradise Alley (Appendix 4) . . . . . . . . . 54
c. Masseys Pond (Appendix 5) . . . . . . . . . . 55
4. Beaver-Release Data Sheet (Appendix 6) . . . . . 56
5. List of Agencies/Organizations who have
reviewed the Delaware Beaver Management
Plan (Appendix 7) . . . . . . . . . . . . . . . . 57
6. An Overview of Beaver Trapping Seasons and
Control Programs in Nearby States (Appendix 8) 58-61
7. Written Comments About the Plan Received from
Other State Agencies, Federal Agencies,
Private Environmental Organizations, or the
Public; Public Meeting (Appendix 9) . . . . . . . 62-107
8. Active Participants in the Development of
Delaware's Beaver Management Plan - plan
research and preparation, technical advice and
consultation, or plan review and comments
(Appendix 10) . . . . . . . . . . . . . . . . . . 108-109

LIST OF TABLES

Table Page No.

1. Beaver Management Plan Participation -- Determination
of Responsible Parties for Management Decisions
and Actions . . . . . . . . . . . . . . . . . . . . . . 41

Figure LIST OF FIGURES

Locations of Beaverdams in Delaware, 1991 . . . . . . . 10

1 Statewide Locations . . . . . . . . . . . . . . . . . . 11

2 New Castle County . . . . . . . . . . . . . . . . . . . 12

3 Kent County . . . . . . . . . . . . . . . . . . . . . . 13

4 Sussex County . . . . . . . . . . . . . . . . . . . . . 14

5 Examples of Beaver-Flow Through Pipes Using
Corrugated Flexible Sewer Pipe and PVC Pipes . . . . . 35

EXECUTIVE SUMMARY

Following inter-agency and public review, the Delaware
Division of Fish and Wildlife has developed a statewide Beaver
Management Plan (BMP) designed to promote environmental benefits
associated with beaver activities, and to contend with socio-
economic problems that beavers may cause. The primary goal of
the plan is to achieve and then maintain a maximum sustainable
population of beavers and their associated wetland habitats
throughout Delaware, located and managed in a mannercompatible
with other land uses and human activities. The BMP presents the
Department of Natural Resources and Environmental Control's
management perspective concerning beavers, and reviews beaver
biology, ecology, and their historical and current population
status in Delaware. Because of the critical environmental values
and functions of Delaware's freshwater wetlands, and because the
State has lost about one-half of its non-tidal wetlands acreage
since colonial times, the beaver's role as a beneficial environ-
mental agent becomes even more important in today's landscape.
However, the beaver's substantial population expansion in
Delaware during the past 20 years, coupled with the increasing
development and urbanization of the State's rural areas, has
increased beaver-caused socioeconomic problems, necessitating
formulation and implementation of a BMP.

The environmental benefits of beaver are discussed in the
BMP, which include: 1) enhancement, restoration or creation of
quality fish and wildlife habitats for wetlands-dependent
species; 2) increased biodiversity within the State's array of
wetland types; 3) enhanced aesthetics and increased recreational
opportunities; 4) floodwater control; and 5) improved water
quality following reduction of dissolved nutrients and retention
of particulate sediments that would have been transported
downstream. Conversely, socioeconomic problems that are
sometimes caused by beavers are also examined, focusing primarily
on beaverdam-caused flooding problems, and on vegetation or
timber damage or loss via cutting or girdling. These
socioeconomic problems may affect residential, commercial or
industrial development; agriculture; forestry; public health or
safety; or transportation.

The BMP addresses factors to consider in determining if
substantial beaver-caused socioeconomic problems are occurring,
and identifies five categories of potential beaver problems:
1) private lands - urban/suburban/residential; 2) tax ditches and
associated aglands; 3) public lands - conservation or
recreational; 4) transportation - roads, highways, railways,
airports; 5) private lands - rural (non-tax ditch). The BMP also
examines response options that could be taken to contend with
substantive beaver-caused problems. The response options
include: 1) live-trapping and transfer of problem-beavers to
carefully-selected release sites; 2) dispatch of problem-beavers,
done by regulated contract trappers or other personnel;

3) implementation of a regulated trapping program open to the
public; 4) installation of water control structures to manage
maximum water levels at acceptable heights in beaverdam wetlands.

The preferred participation, roles and responsibilities of
various government agencies and personnel in implementing a BMP
are given in the plan. The potential types of costs in
implementing a BMP, along with recommendations for cost-shared
activities, are provided. A listing of management options to
manage beaver-abandoned beaverdam wetlands is also given.
Finally, the necessity for better public education and knowledge
about beavers and their activities, needed for the public to
become more tolerant of beavers and thus expand the beaver's
environmental benefits, is discussed.

In order to implement the BMP, the following action-steps
are recommended, dependent upon available resources:

1) In order to contend with excessive beaver densities and
reduce nuisance problems, initiate a regulated,
controlled trapping season open to the public. Only
licensed trappers could participate, using prescribed
methods in designated zones during specified seasons.
The harvest goals would be conservatively set in order
to avoid overharvesting, with the catch carefully
monitored and analyzed.

2) Continue a regulated "contract" trapper program to
address beaver problems that still remain or which
cannot be handled via a public open season; remedies
under the "contract" trapper program include dispatch or
live-trap and relocation.

3) Designate Division of Fish and Wildlife biologists to:

a. Design, implement, monitor and analyze controlled
harvests by licensed trappers during zoned seasons
open to the public;

b. Make technical determinations and recommendations
to landowners, on public and private lands, whether
or not a beaver complaint is a substantive problem
needing remedial action;

c. Make technical determinations and recommendations to
landowners, on public and private lands, of the
preferred remedial actions to contend with
individual substantive problems;

d. In order to promote the distribution or recovery of
beavers in suitable areas throughout Delaware which
do not yet have a desired population density of
beavers, continue a program which solicits,

evaluates and inventories potential relocation sites
for problem-beavers caught elsewhere in Delaware;

e. Coordinate (or in some special cases supervise or
perform) the live-trap and relocation program for
problem-beavers;

f. Perform casual monitoring at release sites of the
activities and colony success of trap-and-
transferred beavers;

g. Help to coordinate (or in some special cases help to
supervise or perform) the use of structural remedies;

h. Contribute to and help to maintain databanks, maps,
inventories, and other records necessary to run a
statewide beaver management program.

4) Using environmental criteria identified in the BMP,
evaluate the environmental importance or quality of
existing beaverdam wetlands throughout the State, done
in order to help determine the level of funds or effort
that might be allocated for treating substantive
socioeconomic problems that may occur at specific sites;
this assessment could be done in advance, or could be
done on a case-by-case basis when (and if) substantive
problems occur in association with existing beaverdam
wetlands.

5) Perform long-term evaluations of the effectiveness and
utility of various structural remedies (e.g. water level
control devices) to contend with beaver-caused problems.

6) Develop cost-share programs for BMP activities that are
desirable and suitable for the cost-share approach.

7) Prepare an informational brochure for distribution to
landowners and the general public about beavers, their
biology and ecology, their environmental benefits, their
potential socioeconomic problems, the solutions or
remedies to such problems, where and from whom to get
further help, etc.

The target audiences for the Beaver Management Plan (in the
form which follows) include the professional technical staff of
the Division of Fish and Wildlife (who will have the primary
responsibility for implementing the Plan), other technical staff
associated with pertinent federal or state agencies charged with
natural resource management or regulation, and technically-
oriented policy-and-decision makers.

vii

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I. Introduction

The Delaware Division of Fish and Wildlife, Department of
Natural Resources and Environmental Control, is the agency
responsible for the management of beavers (Castor canadensis) in
Delaware. The Division of Fish and Wildlife is mandated by
Section 8005, Title 29, of the Delaware Code to protect and
onserve Delaware's wildlife resources. The Division's management
philosophy to implement the provisions of this statute is given
C

in Appendix 1. The goal for formulating a Beaver Management Plan
is to provide guidelines and criteria for the management of
beaver populations, on public and private lands, in Delaware.
While this management plan is designed to be as comprehensive and
flexible as possible, it should be considered a dynamic document
subject to on-going review and could be modified as needed.

Beaver have not been harvested commercially in Delaware
since colonial times due to diminished populations caused by
over-trapping, which almost led to their extirpation from the
state. In recent years however, beaver populations have
rebounded and expanded into areas of the state where their
activities are sometimes incompatible with primary land-use
practices. As a result, there has been an increasing number of
landowner complaints concerning beaver activities, including the
flooding of agriculture lands, woodlands, personal property, and
highways, plus timber damage and cutting of ornamental trees. At
the same time, increased beaver activity has provided
environmentally-beneficial effects including the creation of high
quality wetlands habitat for a variety of wetland-dependent flora
and fauna; removal of excess dissolved nutrients; particulate
sediment and toxicant retention; floodwater detention; and
enhanced aesthetic values and recreational opportunities. It is
the Department's goal to promote these environmental benefits in
a manner compatible with other land-use practices and goals.

Ii. General Policy and Plan Purpose

Beavers and their activities can provide substantial
environmental benefits, in particular valuable fish and wildlife
wetland habitats and improved water quality. It is the
Department's policy to promote the establishment, expansion and
recovery of beaver in Delaware in locations where unacceptable
socioeconomic problems will not occur. The promotion of this
policy will involve conflict assessment and resolution regarding
beaver-induced environmental modifications and the socioeconomic
interests of agriculture, forestry, highways and transportation,
public health and safety, and industrial, commercial or

residential development. Determining and implementing conflict
resolutions will also incur expenses to both public and private
sectors. However, these resolvable concerns should not outweigh
the environmental benefits that a managed beaver population could
provide in Delaware, and thus the Department views the beaver as
a beneficial environmental agent.

In order to promote a managed beaver population in Delaware,
the Department has developed a "Beaver Management Plan" focused
on three primary topics:

1. Promotion of the environmental benefits provided by
beavers;

2. Evaluation procedures and guidelines for determining
where and when beavers are causing unacceptable socio-
economic impacts;

3. Action procedures and guidelines for determining and
taking corrective measures to address unacceptable
socioeconomic impacts.

The primary goal of the plan is: to achieve and then
maintain a maximum sustainable population of beavers and their
associated wetland habitats throughout Delaware, located and
managed in a manner compatible with other land uses and human
activities.

A statewide quantification of the maximum sustainable
population goal is not yet possible, since we do not know the
number of remaining unoccupied sites in the State where the
habitat is suitable for beaver colonization and for which beaver
activities will not create substantive socioeconomic problems.
The Plan's intent is to eventually reestablish beaver colonies
throughout all of Delaware's watercourses, wherever beaver find
suitable habitats and where they do not cause substantive
problems. When all such sites are eventually occupied, whether
this maximum occupancy be on a local, regional or statewide
basis, then beaver population growth beyond maximum levels of
distribution and abundance (i.e. beyond maximum sustainable
populations on local, regional or statewide bases) must be
proactively curtailed. It is not necessary nor desirable that
100% of all potentially inhabitable sites must be colonized (on
local, regional or statewide bases) before this curtailment
begins, since it is desirable to maintain (or create) temporarily
vacant areas which may eventually be colonized by future beaver
generations.

III. Biology and Ecology

1) Description

The beaver (Castor canadensis) is a member of the order
Rodentia and is the largest rodent in North America. An adult

beaver usually weighs between 35-70 pounds and can be almost four
feet long. The beaver's coat consists of underfur and long guard
hairs giving it a course appearance, and can vary in color from
yellowish-brown to reddish to almost black. Two prominent
characteristics of beaver are a paddlelike tail and large
incisors which grow continuously. The beaver's skeleton is
heavier than animals of similar size in order to withstand the
stress of gnawing and cutting of hardwoods. The beaver is
specialized for aquatic life, with its hind legs and feet, webbed
toes and flattened tail all adapted for swimming. The nostrils
are closeable, the ears have valves that can close, and skin
flaps seal the mouth leaving the incisors exposed for carrying
tree branches underwater.

2) Range and Habitat

Beaver can be found throughout most of North America from
the Atlantic to the Pacific (including most of Alaska) and from
Canada to Florida. It is believed that the beaver's historic
range included all areas of North America that contained plants
and water suitable for its winter survival. Typical habitats
include rivers, impoundments, lakes, streams and tributaries that
have adequate flow for damming to provide seasonably-stable water
levels. Although beaver can occur in steep, rocky habitats, they
prefer areas of relatively flat terrain.

Beaver habitat must contain all of the following: (1) a
stable aquatic habitat which provides adequate water; (2) a
channel gradient of less than 15%, with less than 6% ideal; and
(3) quality food species present in sufficient quantity (Williams

3) Dens, Lodges, Dams and Other Structures

Beavers live in excavated bank dens, or build dome-sha-ped
lodges constructed of limbs or branches'from felled trees and
saplings and then caulked with mud. A bank den or lodge has at
least two entrances and may have four or more. Bank dens are
often dug and inhabited when beavers first move into an area,
occupied as they build their dams and lodges. Additional bank
dens are often built to provide strategic locations where they
can rest or take refuge. In some areas where water levels are
already adequately deep and stable, or conversely where streams
or rivers are shallow but subject to severe floods, dams are not
built and beavers sometimes live their entire lives in bank dens.
Beavers living in pond lodges occupy a dry chamber above
waterline, which is created by cutting away brush or sticks in the
chamber's ceiling and trampling the material under foot. Lodges
can be constructed in the center of ponds as island houses, or
are sometimes built along pond edges, usually overtop the den of
a bank burrow which has been abandoned as water level rose.
Lodges can rise up to 7 feet above pond bottom, and can be more
than 14 feet in diameter.

The length and height of beaverdams, made from limbs, branches,
stones, mud and other debris, depends on what is necessary to
stop the flow of water and create a pond. Beavers are constantly
working on either increasing the size of their dams or on
maintaining or repairing what they've built. Beaver dams are
designed to maintain water levels above lodge entrances and to
provide open water for easy swimming, needed to expand and allow
safe access to food sources. Beaverdams usually average less
that 6 feet high, but in narrow, steep-sided vallyes have been
found to be up,to 15 feet high. Thickness of a dam's base is
usually from 8-18 feet, while width at the top is from only a few
inches up to 3 feet. The length of dams is very variable,
ranging from only several feet long when blocking culverts,
underpasses or narrow corridors, up to over 2000 feet long in
some western meadow valleys. A single beaver colony may build
one or more secondary dams within a few hundred feet of the
primary dam, in downstream or upstream locations, relieving the
main dam from excessive water pressures, and providing additional
waterborne access to new feeding areas.

Beavers are also well known for excavating travel canals
(inundated trails) connecting their dam-formed pools or to
provide access to feeding sites. Another highly visible
structure created by beavers is a food pile, composed of unpeeled
limbs, branches and twigs, deposited near the lodge to provide a
winter food supply.

4) Food Habits

Beaver will eat the leaves, twigs and bark of most species
of trees and woody plants, but prefer species such as aspen,
poplar or, in Delaware, red maple, cottonwood, willow, alder,
sassafras, sweetgum, blackgum, dogwood, holly, oaks and even
pine. An ideal food situation for woody vegetation would be a
stand of preferred food trees (e.g. aspen, poplar, willow,
cottonwood, alder) within 100 yards of a watercourse, having a
size from 1-6 inches dbh with 40-60% canopy closure (Allen,
1982). Beaver also feed on herbaceous and aquatic plants, vines,
roots, the fruit of woody plants, and sometimes even agricultural
crops such as corn or soybeans. Aquatic vegetation such as
arrowhead or duck potato (Sagittaria spp.), duckweed (Lemna
spp.), pondweed (Potamogeton spp.), water weed (Elodea spp.), and
water lilies (Nymphaea spp.) are preferred food when available.
If present in adequate amounts, the roots and rhizomes of water
lilies provide satisfactory winter foods, and may result in
little cutting or caching of woody materials for winter sources.
When one considers that beaver have even colonized irrigation
ditches in the Great Basin Desert of Nevada, it is apparent that
they are able to eat a wide variety of foods.

Most trees for food, shelter or dams are felled within 30
yards of the lodge; however, beaver will travel and cut choice
foods up to 100-200 yards away. Beavers appear to prefer

herbaceous vegetation, when available, over woody vegetation
during all seasons of the year (Jenkins 1981).

5) Wetlands Successional Cycles

When food supplies at a site become too scarce, or when
beavers cannot raise their dams to create new waterborne access
to new food sources, beavers will abandon the site. When this
happens, deterioration of the dam eventually occurs and water
levels drop, causing the beaverdam wetlands to go through a
successional wetland series from permanently-inundated wetlands
to seasonally-inundated wetlands to temporarily-inundated
wetlands. This successional series, after several decades, may
culminate in a wet meadow with a shallow central channel. As
woody growth recolonizes the perimeter of the meadow and
encroaches across the open meadow itself, food conditions may
again become suitable for beaver to return to the site and
construct a new dam, starting the wetlands successional cycle
anew.

The wetlands successional cycle created by beaver activities
forms a complex of wetlands types, with the wetland type at any
specific site being a transitory stage, different than what
existed a decade before and destined to be different ten years
later. At any one time in a region where beavers have been
established for several decades, there will be a mosaic of
wetland types of different ages, forming a diversity of wetlands
habitats. Thus, beavers and their activities are significant
agents in promoting biodiversity, creating a series of ephemeral
wetland habitats critical to the perpetuation of many endangered,
threatened or rare plant and animal species. Active or abandoned
beaverdam wetlands in Delaware are important quality components
of the State's freshwater wetlands array, contributing to both
the State's proposed Type I wetlands (unique biotic assemblages)
and proposed Type II wetlands (moderately-wet to very-wet
wetlands), plus restoring or expanding proposed Type III wetlands
(marginally-wet wetlands) in peripheral areas.

6) Reproduction and Development

Beavers are monogamous and are believed to pair for life.
They are sexually mature when they are 1-1/2 years old, but their
first litter usually occurs at age three. Breeding usually
occurs between January and March with a subsequent gestation
period of about 100-110 days. Copulation takes place either in
the water or in the lodge or bank den. Litter size varies with
the age of the female and quality of habitat. A typical litter
is three to four kits with a range from one to nine, and they are
born fully-furred with eyes open. The female produces one litter
per year, with the kits typically born in May, and the mother
nurses the young for approximately 6-8 weeks. At birth a kit
weighs about one pound, reaches 4 pounds when weaned, and grows
to 15 pounds by the start of its first winter.

The young are usually displaced from the colony by the
adults after approximately two years of age, in March following
their second overwintering in the lodge or den, in advance of the
arrival of the year's new litter. Thus, during mid-winter within
most colonies, there's usually the two adult parents, a few
yearlings (sub-adults) from the litter two years before, and a
few older kits from the current year's litter. The displacement
of offspring from the colony after two years of development
causes the geographical expansion of the population, which
sometimes leads to new socioeconomic problems as the dispersed
young adults build new dams, mate and establish new colonies.
While the dispersion of some young up to 150 miles from parental
colonies has been documented, average emigration distances range
from 5-10 stream miles. Another type of displacement, but which
is voluntary in nature, is when the male parent leaves the lodge
after the kits are born, staying out until the kits are fully
weaned. During this time, the male takes up solitary residence
in a bank den, but remains within the colony's habitat, working
on dams, food piles, and the lodge.

7) Population Structure and Density

Based upon population data of trapped beavers from
widespread areas across North America, and disregarding trapping
biases, the mean percentages of kits (young-of-the-year), sub-
adults (yearlings), and adults (two years and older) in an
average beaver population is 30t, 23%, and 47%, respectively.
Sex ratio in beavers is almost even, with total population
averages from widespread areas yielding a male:female = 105:100.

Not surprisingly, reported population densities for beaver
are widely variable, dependent upon habitat quality and harvest
or mortality factors. Beavers are highly territorial, and will
mark their territories with scent mounds. Beaver colony
territories are distinct and non-overlapping, with usually no
more than one colony per 0.5 miles of stream length. Densities
are reported either as number of colonies per unit area or per
length of stream. Examples of the former are as follows: colony
densities in Algonquin Park, Ontario = 0.98-1.97 colonies per
square mile; in the MacKenzie Delta, Northwest Territories = 1.01
colonies per square mile. Examples of the latter are: colonies
along streams in New Brunswick = 0.14-0.22 colonies per stream
mile; in Alaska = 0.56-0.77 colonies per stream mile. The
typical densities of colonies in favorable habitat range from 1-2
per square mile. Densities greater than 1.98 colonies per stream
mile are estimated to exceed saturation maximums in New York,
while saturation is considered to occur in Alberta at only 0.64
colonies per stream mile, but saturation doesn't occur in Alabama
until densities exceed 3.0 colonies per stream mile. The mean
number of beavers per colony, based on survey data from 22 states
and provincesf- averages 5.2 animals per colony; an extreme number
of animals per colony would be 12 individuals.

8) Mortality

Beaver have a normal life expectancy of about 10 years in
the wild, although captive animals may live to 21. Numerous
predators affect the beaver throughout its range. In wilderness
areas these include man, coyotes, bobcats, wolves, bears and
wolverine. In Delaware, the major predator on adult beavers is
man, but both feral and domestic dogs may also kill adults.
Young kits may be killed by river otter or mink. In addition,
there can be territorial conflicts between beaver and otter.
Tularemia, a bacterial disease, has caused mortality and
decimation of beaver populations in the Rocky Mountain and
northern states, but is not common in beavers in the southeast.
Giardiasis, a protozoan parasite, is carried by beavers but does
not appear to severely affect them; however, excretion of this
parasite by infected beavers appears to have contaminated water
bodies over a wide geographical range (e.g. Maine, Texas), and
may lead to outbreaks of the disease in humans who drink
untreated surface water. In some regions, snow melt and heavy
spring rains can cause flooding, which may destroy lodges and
drown beavers under the ice. Starvation, particularly in
northern high latitudes near the range edge, can be a mortality
factor.

IV. Status and Trends of Beaver in Delaware

1) Historical Distribution of Beaver in North America, the mid-
Atlantic, and Delaware

Beaver were essential providers of fur, food and other
important products in early settlement days. Beavers ranged over
all of boreal and temperate North America, as long as there was
acceptable habitat. Before European settlement of North America,
the total continental beaver population was estimated to be 60-
400-million individuals. It is probable that almost all-st--reams
or creeks on the Delmarva Peninsula during pre-colonial times
ere staircase-series of beaverdam-regulated flowages. However,
intensive trapping by early settlers reduced their populations to
alarmingly low levels. Extensive removal of beavers in North
America began in the early 16001s. For example, 10,000 beaver
per year were estimated to be harvested in Ma�-s-achusetts-and
Connecticut during the 16201s, and 80,000 beaver per year were
estimated to be taken from the Hudson River valley and western
New York during the 1630's. Beaver were probably almost
extirpated in Delaware by the mid-18001s. The current population
of beavers in North America is estimated to be between 6-12-
million individuals. Gregg (194-8-)--d-u-rfiina-r-iz-4e--d--the-naE-i@on-a-l-
situation when he stated that "the ground swell of conservation
consciousness brought c-*_ttention to the beaver as a vanishing
species, and due to widespread interest, stringent or total
protection was provided by law almost everywhere in the United
States by World War I."

An indication of the widespread distribution and historical
abundance of beaver in Delaware can be gleaned by examining the
placenames for Delaware's streams, creeks and other geographical
features. In New Castle County, there are two streams named
Beaver Branch, plus a Beaver Creek; Beaver Valley is an area near
Wilmington. Kent County has three streams named Beaverdam
Branch, plus two Beaverdam Ditches and one Beaver Gut Ditch.
Sussex County has three streams named Beaverdam Branch, plus one
Beaver Dam Run, a Beaverdam Creek, and a Beaverdam Ditch. One
may also find in Sussex County a Beaverdam Bridge, a Beaverdam
Cemetary, and an area called Beaver Dam Heights.

An illustration of how rapidly beaver can repopulate an area
or region, when they are protected and allowed to occupy the
suitable habitats that remain, is provided in Pennsylvania, where
beavers were essentially extirpated by the early 1900's. Between
1917 and 1920, 28 pairs of beavers were imported from the upper
Great Lakes region by the Pennsylvania Game Commission and
released in suitable habitats. By 1930, over 1500 known colonies
were documented in 49 Pennsylvania'counties. During the first
trapping season in Pennsylvania in 1934, 6400 beavers were taken
(Hilfiker, 1991).

In 1935, the Delaware Board of Game and Fish Commissioners
purchased three pair of beaver from Maine in an attempt to
restore beaver in Delaware, and released one pair in each
Delaware county (New Castle, Kent and Sussex). By 1943, it was
estimated that these initial releases had increased to a total of
24 individuals. Additional beaver have also since moved into
Delaware from Maryland, where populations were not historically
reduced to the very low levels which occurred in Delaware.

The Division of Fish and-Wildlife's Wildlife Section started
to respond, as a non-mandated public service, to beaver-problem
complaints in the early 19701s. In 1972, the Wildlife Section
heard only one public complaint, and received four public
complaints in 1973; throughout the remainder-of the 19701s,
beaver complaints remained at similar low levels per year. When
complaints were addressed by the Wildlife Section during the
19701s, the typical response was to live-trap problem-beavers and
transfer them for release in Maryland, or to dispatch problem-
beavers on-site. The Division's Enforcement Section started to
respond to beaver complaints in the early 1980's, when problems
started becoming more numerous. Simultaneous with the 1980
decision to transfer responsibility for handling problem-beavers
to the Enforcement Section, the Division made a policy decision
to live-trap and transfer for in-state release (at suitable
sites) as many of the problem-beavers as practical, done in order
to promote the environmental benefits of beaver activities in
Delaware. Concomitant with this decision was a realization that
the Division would also have to be as responsive as practical to
public complaints about beaver nuisances, whether the problems be
real or only perceived.

Beaver populations in Delaware greatly increased
and expanded throughout the 19801s, and have now reached a level
of nuisance taxing the capability of the Division's staff and
resources to provide satisfactory responses. In 1990, the
Division's enforcement officers spent 550 man-hours attending to
beaver problems in New Castle County and-northern Kent County.
Also in 1990, Division enforcement officers spent at least 150
man-hours attending to 28 probl'em-beavers in southern Kent County
and Sussex County, which was time withdrawn from their
enforcement duties and responsibilities. The necessity for this
level of response effort not only reflects an increase in beaver
numbers, but also the rapid development and urbanization of
formerly rural areas in Delaware, creating more beaver-human
conflicts.

2) Current Status of Beaver in Delaware

Beaver are currently protected in Delaware by state statute,
and have been protected by law since the late 1920's. By Section
701, Chapter 7, Title 7 of the Delaware Code (see Appendix 2),
beavers are considered game animals and thus protected. Limited
trapping of beavers, from December 15 through March 15, done only
under a special permit issued by the Division of Fish and
Wildlife, may be done by landowners (or their agents) who have
beaver problems or damage on their property. Each landowner's
name (and any contracted trapper) must be listed on the permit,
and all beavers caught must be presented to the Division for pelt
tagging. At other times of the year, problem-beavers may still
be trapped under a special animal damage control permit,
applicable to many species, which is also issued by the Division
of Fish and Wildlife. Additionally, as an ad hoc service
function to citizens complaining about beaver nuisance problems,
Division of Fish and Wildlife enforcement officers (or their
agents) have also trapped and removed problem-beavers.

3) Current Distribution and Population of Beaver in Delaware

An initial survey was conducted in 1990 in order to
determine the locations of existing dams and lodges in Delaware
(see Figures 1-4 for beaverdam sites). There are at least 126
active beaverdams in Delaware, yielding an estimated total
statewide population of 750-1500 beavers. This number is based
on the premise that each "beaverdam wetland" has at least one
colony, although each designated site may have more than one dam
in close proximity to the main dam. Using an average value of
5.2 beavers per colony yields 655 beavers in the known 126
sites. An extra 95 beaver were added to the total to bring the
minimum estimation to 750 beavers statewide, to account for
overlooked or unknown colonies, particularly in Sussex County
(the extra 95 beaver would represent an additional 18 colonies).
The minimum estimation was then doubled to yield a maximum
statewide estimation, based primarily on subjective knowledge
that "bank beavers" are also a substantial component of
Delaware's population, but how substantial is truly a

Figures 1-4

Locations of Beaverdams in Delaware, 1991

Figure 1 Statewide Locations (126 sites)
Figure 2 New Castle County (33 sites)
Figure 3 Kent County (71 sites)

Figure 4 Sussex County (22 sites)

The number of beaverdams in Sussex County, particularly in
the western and southern portions, is probably an underesti-
mation, since these areas are relatively remote and the
frequency of beaver-complaints is low.

All

Figure 1. Statewide Locations

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* ** A Wilml ton

*** NEW CASTLE .
K> BEAVER SITES

(1990)

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KENT COUNTY
BEAVER SITES

(1990)

Dover

Figure 3

- -.- ==name= mom now* @

SUSSEX COUNTY

BEAVER SITES

(1990)

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Figure 4

guesstimate. Beaver activities control the hydrological regimes
on at least a few thousand acres of Delaware's remaining 130,000-
150,000 acres of non-tidal wetlands. Survey data will be updated
periodically in order to document changes in trends and
distributions throughout the state. The frequency and methods
for survey updating will be developed later.

4) Future Population Growth of Beavers in Delaware

The population expansion of beavers in Delaware has been
substantial throughout the 19801s. However, the amount of
suitable sites for future population expansion has undoubtedly
declined since the early 19801s, although potential sites still
exist, particularly in rural areas of Sussex County and southern
or eastern Kent County. Potential suitable sites for future
colonization (or release) are discussed in more detail in Section
VIII-lA and 1B.

Because of the population expansion throughout the 19801s,
it is probable that the rate of population growth is now slowing
as more and more suitable sites have been occupied. However, the
total number of beavers will continue to grow for the foreseeable
future, creating more socioeconomic conflicts caused by a still
burgeoning total population and dwindling suitable habitats.
Adults living in the habitats where beavers do not cause socio-
economic problems will continue to produce offspring, which may
cause problems following the offspring's emigration from parental
colonies.

A quantified estimation of future beaver populations in
Delaware is somewhat difficult to predict, but if we make several
assumptions, estimations can be generated based on projections of
past trends. Prior to the rapid expansion of beavers in Delaware
during the 19801s, a liberal estimation of the number of active
beaver colonies in the state during the late 1970's would be 20.
Thus, for the 11-year period from 1980 through 1990, the number
of beaver colonies would have increased by 106 (to today's
estimate of 126 colonies statewide), an average increase of 9.6
colonies per year. However, this average rate of increase is
misleading, since what we really need to know is the realized
rate of increase (r) per year, because accelerated population
growth is an exponential function. A yearly population increase
of about 16.7% (r=0.167) from 1980 through 1990 would increase
the number of colonies from 20 to 126 during this period.

Making the assumption that the annual rate of future
increase will be an exponential function with r = 0.167 (which
assumes that future reproduction and mortality rates will not
change from the past, that the availability of suitable habitat
for future colonization will be the same as in the past, and that
our past management policies and practices will continue), then
some projections of future beaver populations in Delaware can be
made. Using an average colony size of 5.2 beavers per colony,
beavers in Delaware could increase from a very conservative

estimate of 655 animals (126 colonies) in 1990 to: 775 animals
(149 colonies) in 1991; 915 animals (176 colonies) in 1992; 1508
animals (290 colonies) by 1995; and 3479 animals (669 colonies)
by 2000. It is quite probable that the limited carrying capacity
of suitable habitats in modern Delaware will never permit such an
expansion, but as the modern carrying capacity is approached
(whatever it may be), we can only expect that beaver-human
conflicts and associated socioeconomic problems will continue to
increase.

An interesting estimation to make, based upon available
density estimates from remaining wild areas in the East, is that
Delaware's approximate 1892 square miles of non-tidal lands could
have supported over 10,000 beavers in pre-colonial times.
Today's beaver population, which has rebounded since the early
19801s, probably represents less than 10% of the State's historic
abundance.

The most effective control for an overly abundant beaver
population, and often the only practical control, is a trapping
(dispatch) program. Experience in other regions suggests that an
annual harvest of one-third of the estimated population can
maintain beaver populations or even allow a slow increase in high
quality habitats (Denny, 1952). Various methods to achieve this
harvest goal, while avoiding overharvesting, include trapping
about 1.5 beavers per colony per year, or trapping each colony
more intensively but on a 2-3 year rotational cycle, or on
completely trapping-out some colonies for a 4-5 year period while
allowing others to remain undisturbed.

5) Examples of Beaverdam Wetlands Habitat in Delaware

Habitat evaluation surveys were conducted at 3 selected
beaver colonies in Delaware during 1990 (Appendices 3-5). Data
collected included information on vegetative cover, fish and
wildlife species present, dimensions of dam, number of lodges or
bank dens, depth of water upstream and downstream of the dam, and
approximate age of the dam (assessed via contacts with landowners
or field staff, or by presence of fresh cuttings). Information
collected will help determine positive and negative aspects of
beaver activities at the selected sites, will also be valuable in
assessing other existing sites, and will also be useful for
determining desirable features of future release sites as beaver
complaints and concerns are addressed. The criteria for
determining a beaver nuisance site vs. a non-problem area were
initially examined at these 3 sites. In some cases an area
impacted by beaver causes problems that are unacceptable to the
landowner, and corrective actions need to be taken. Each of the
3 sites was evaluated to determine whether it is a problem site
or not, based upon complaints received, flooding potential, and
on-site and adjacent land-use practices.

Site #1 - Garrisons Lake

The first site that was evaluated is above Garrisons Lake
(Kent County) (Appendix 3). A pair of Maine beavers were
introduced into this area in 1935 (Bonwill and Owens 1939). They
were released into the Willis Branch which flows into Garrisons
Lake. This site was selected for habitat evaluation because it
probably represents a site having no apparent socioeconomic
problems caused by beaver activity.

Site #2 - Paradise Alley

The second site chosen for evaluation is located south of
the town of Felton (Kent County) on Paradise Alley Road (Appendix
4). This area has some beaver-caused problems, including
flooding of private property where the landowner perceives a loss
of commercial timber, cutting of ornamental trees, and the
potential "undermining" of a train trestle. A water control pipe
was installed through the dam to attempt to maintain a constant
desirable water level; however, beaver effectively plugged the
pipe, causing it to fail. (This led to a conclusion that further
research needs to be done on different types of beaverdam water
control pipes - see structural remedies, Section VIII-3).

Site #3 - Massey's Pond

The third site for evaluation is currently having no
apparent adverse impacts due to beaver activity. The location of
the site is in a existing millpond called Massey's Pond (Kent
County) (Appendix 5). Beaver have built a lodge and are using
the pond, but they do not appear to be building any dams.

V. Environmental and Socioeconomic Benefits of Beavers and
Beaverdam Wetlands

Beaver activities provide many environmental benefits, with
particular emphasis on fish and wildlife habitat, recreation and
aesthetics, flood control, and water quality. In terms of
improving the quality and quantity of Delaware's freshwater wet-
lands, there is probably no more cost effective agent to enhance,
restore or create wetlands environs than the beaver. A beaver
management program, which promotes beaver colonization where
socioeconomically feasible, can probably do as much as man's
efforts (if not more) to improve Delaware's freshwater wetlands,
achieved at a fraction of the cost. Reestablishment of the
historical distribution and abundance of beaver in Delaware, done
wherever socioeconomically feasible, would be a very desirable
habitat management goal and tool.

1) Quality Fish and Wildlife Wetlands Habitat

Beavers are adept at modifying their environment to suit
their needs. Beaver activity also enhances, restores or creates

wetlands habitat valuable for a diversity of wetiand-dependent
flora and fauna. Many species of waterbirds, such as grebes,
wood ducks, black ducks, mallards, teals, coots, gallinules,
kingfishers, herons, egrets, bitterns, and rails, benefit from
beaverdam wetlands, using these wetlands for breeding, nesting,
brood rearing, feeding, or migratory resting. Other birds such
as woodpeckers, swallows, woodcock, snipe, red-winged blackbirds,
and several species of warblers and sparrows find beaverdam
wetlands to be suitable nesting or feeding habitats. Fishes in
Delaware such as minnows, shiners, chubs, bullheads, madtoms,
darters, and sunfishes are associated with the deeper pools of
beaverdam wetlands. Aquatic invertebrates such as snails,
mussels, clams, crayfishes, and immature and adult forms of
numerous aquatic insect species can be abundant in the shallow
waters of Delaware's beaverdam wetlands. Many species of frogs,
toads, salamanders, water snakes, and aquatic turtles are
provided with quality habitat in Delaware by beaver activities.
In addition to beavers, other Delaware mammals frequently found
in beaverdam wetlands include muskrats, mink, raccoon, and river
otter. Beaverdam wetlands may also support rare and endangered
species of plants and animals (see discussion of wetlands
successional cycles in Section 111-5).

Beaver in many cases convert marginally-wet wetlands with
temporary or short-seasonal hydrologic regimes into more
functionally valuable, wetter habitats having extended or
permanent surface inundation. Quite often timber of low
commercial value is converted by beaver-caused inundation into
dead standing timber important to species such as woodpeckers and
nesting wood ducks, hooded mergansers, tree swallows, bluebirds,
screech owls, kestrels, and other cavity nesters using abandoned
woodpecker holes. However, trees of commercial value are
sometimes also killed by beaver-caused inundations, so the
creation of quality habitat for cavity-nesting birds may
sometimes involve undesirable socioeconomic costs- For example,
swamp white oak (Quercus bicolor) trees may be killed by long-
term flooding; this species has a very high commercial value for
domestic veneers and cooperage, and is Also sought by Europeans
and Asians as a substitute for true white oak (Quercus alba)
(T.A. Kaden, pers. comm.).

An in-depth example of the importance of beaverdam wetlands
for quality wildlife habitat is provided by the black duck (Anas
rubripes), which is a species of special concern in Delaware and
within the Atlantic Coast Joint Venture of the North American
Waterfowl Management Plan. Beaver ponds are preferred habitats
for black ducks throughout their range, and account for a major
portion of black ducks produced in eastern Canada and New
England. For example, beaver ponds in New Brunswick are
estimated to produce 9,000-11,000 black duck broods annually
(each brood typically has 8-10 ducklings). Although beaver ponds
in the Northeast are now much more numerous than in the mid-
Atlantic region and represent a major portion of the available
breeding habitat, such habitat type use to be found throughout

the black duck's breeding range, which extends southward to
northeastern North Carolina. The loss of beaverdam wetlands in
the mid-Atlantic has undoubtedly played a role in the black
duck's population decline.

The importance of beaverdam wetlands as black duck breeding
habitat varies with age of the ponds. Generally, the most
productive breeding sites for black ducks are on active beaver
ponds less than 3 years old. It may be that older beaver ponds,
as in older man-made impoundments, provide fewer invertebrates
and other foods important to breeding waterfowl and their broods.
Thus, establishing new sites and reactivating drained or old
ponds, courtesy of new beaver activity, could significantly
increase black duck breeding habitat. Black ducks have been
observed in Delaware's beaverdam wetlands, but the black duck's
current frequency and intensity of use of this habitat type has
not been quantified in Delaware.

2) Recreation and Aesthetics

Beaverdam wetlands provide interesting areas for nature
study, photography, and other forms of outdoor recreation in
aesthetically-pleasing surroundings, as well as new or increased
opportunities for hunting, fishing or trapping.

3) Flood Control

Beaverdams, and the wetlands that they create, slow
downstream water movement and allow for a more controlled release
of floodwaters. This reduces erosion of stream beds, decreases
downstream flooding, and allows dammed water to be absorbed by
the soil, raising groundwater levels. Higher groundwater levels
may stimulate crop growth in some soils, especially where beaver
are active in tax ditches near agricultural fields. Beaver ponds
may also serve as a limited source of water for irrigation
activities. However, the current role of beaverdam wetlands in
Delaware for flood control and water supply has not been
quantified.

4) Water Quality Effects - Dissolved Nutrients and Particulate
Sediments

Beaver ponds serve as settling basins for waterborne
particulates and as filters for removing dissolved nutrients
(e.g. run-off from agricultural fields). Emergent and submergent
aquatic vegetation in beaver-created wetlands can substantially
remove excess dissolved nutrients from ponded water. Dennis
Whigman of the Smithsonian Institution recently compiled an
unpublished review of the impacts of shallow freshwater
impoundments on water quality. In Whigman's review, he cites
studies of beaver-influenced systems published by Robert Naiman
and colleagues from 1984-1987. Their research focused on
ecosystem processes, community structure, and carbon dynamics
(including production of invertebrates and fishes) in beaverdam

wetlands.

The main conclusions of the Naiman et al. studies in
beaverdam wetlands were as follows:

a. Low-order streams (Strahler orders 1-5) have a low
processing efficiency, high storage capacity, and high
export of carbon. The low order streams act as
important organic carbon sources for consumers in
downstream areas.

b. Microbial production was relatively constant across all
stream orders indicating that available carbon was
relatively constant in different stream orders.

C. Most of the carbon that is transported is in the form
of dissolved organic carbon.

d. The presence of beaver impoundments resulted in greater
amounts of dissolved organic carbon export per unit area.

e. Beaver impoundments result in an increase in stream
stability, retention capacity, and processing
efficiency of drainage systems.

The findings of Naiman et al. indicate that beaverdam
wetlands, in comparison to sl_re@i_ms and adjacent riparian habitats
that are not dammed and flooded, function differently. In net
terms of overall water quality, downstream water having passed
through a beaverdam wetlands has a more desirable composition
than downstream water which has not traversed beaverdam environs.
The amount of sediment retained within beaverdam wetlands can be
very substantial, amounting in volume to 350-500 times the volume
of wood in the dam. For example, a small beaverdam consisting of
10 cubic yards of wood can retain (throughout the life of the
site as an active beaver colony) up to 5000 cubic yards of
sediment, preventing this potential sediment load from running
downstream to ponds, lakes or open estuaries.

Beaver activities also substantially change the total
amounts of carbon inputs, carbon standing stocks, and carbon
outputs. Beaverdam wetlands are more efficient for retaining and
processing organic carbon; little material, relative to the
amount received, is transported downstream. The standing stock
of carbon in an undammed wetlands may turnover (i.e. be replaced
or passed through the system) up to 7 times faster than in a
beaverdam wetlands. Conversely, the standing stock of carbon in
a beaverdam wetlands may be up to 20 times greater than an
undammed wetlands, providing a large reserve of carbon and other
nutrients needed for ecosystem stability. This nutrient pool is
manifested in an increase in the total density and biomass of
aquatic invertebrates in beaverdam wetlands. While there are
species shifts of aquatic invertebrates in beaverdam wetlands
from predominantly shredders and scrapers (in undammed streams)

to collectors and predators (in beaver ponds), the total number
of species stays similar, and both organism density and biomass
per unit area increases 2-5 times in beaverdam habitats.

Finally, beaverdam wetlands help to reduce the downstream
transport of dissolved nutrients, helping to reduce
eutrophication problems in receiving waters when dissolved
nutrients become excessive. For example, increases in flooded
land caused by beaverdam blockage increase the lateral extent of
anaerobic surficial layers, which helps to reduce (via
denitrification to atmospheric nitrogen) nitrate and nitrite
loads flowing into beaverdam wetlands, reducing downstream
transport of these dissolved nitrogen forms. Increases occur in
available soil nitrogen as a result of flooding, but this is
primarily in the form of ammonia, which is absorbed by rooted
macrophytes or anaerobic microorganisms, or may be immobilized
onto negatively charged soil particles, or may diffuse into the
thin, upper aerobic soil layer, where it might be nitrified and
then rapidly exposed to denitrification in a nearby anaerobic
zone, or it might be volatilized directly to the atmosphere.

5) Summary of Attributes

The following synopsis of beaver activities and their
environmental benefits is quoted from Hilfiker (1991):

"The beaver is a remarkable animal. No creature
except man surpasses him in his ability to change his
environment to suit his special needs. He builds dams,
maintains ponds, clears roadways, digs canals, and
conducts extensive logging and lumbering operations.
These things he does in order to survive, but the dams
he builds spread out flood waters, slow them down, and
reduce their capacity to do damage downstream. The
ponds store water against times of scarcity and act as
settling basins for silt carried downstream during
periods of high water. The clearings around the ponds
let in light and create edge conditions. Wherever
beavers build their ponds, a vast variety of living
things are attracted to them as iron filings are drawn
to a magnet."

VI. Socioeconomic/Envirorunental Problems Caused by Beavers

1) Flooding Problems

Beaver activity may cause serious flooding in low-lying
areas, particularly in areas with minimal lateral relief. This
can result in residential, commercial or industrial property
damage; damage to roads, railways or airports; loss of
agricultural crop production; and loss of commercial timber
stands.

In the State of Delaware, many agricultural problems are
related to poor drainage or flooding. The tax ditches which
border many agricultural fields are designed to drain wet areas
to improve the capability for cultivation. Beavers sometimes
build their dams in these ditches, causing water to back up,
flooding the fields. The damming of these ditches also
interferes with normal water flow, causing slow drainage, which
can result in reduced crop production. The Delaware Forestry
Section (Delaware Department of Agriculture) also has concerns
about commercial timber loss due to beaver-induced flooding and
tree girdling. Beaver activities may also result in damming-up
highway culverts and railroad right-of-ways, or the flooding of
residential yards and homes. Overall, flooding is probably the
primary problem related to beaver activities.

The areas flooded by beaver can sometimes create breeding
habitat for nuisance and potentially health-hazardous mosquitoes.
However, in most cases mosquito production problems may actually
be reduced, since the alternately wet-dry habitats required for
egg-deposition and larval maturation of many pestiferous,
temporary-pool breeding mosquitoes (e.g. Aedes spp.) may be
usurped by beaver-caused permanent inundation. Mosquito species
that will breed in permanent standing water (e.g. Culex spp.;
Anopheles spp.) typically do not fly as far as temporary-pool
breeding mosquitoes when in search of blood meals, and the larval
populations of permanent-water breeding species are often kept in
check by larvivorous fishes resident in beaver ponds.

Many rare or endangered plant species may be sensitive to
excessive inundation, and hence killed by prolonged flooding of
an area. Ironically, many of Delaware's rare or endangered
wetlands plant species are now found in wetlands that were
formerly created or occupied by beaver, and these areas are now
in later successional stages following beaver abandonment (or
removal). The long-term perpetuation of certain rare or
endangered species in Delaware may depend upon wetlands
successional cycles, and the beaver may be a primary agent for
triggering or controlling these cycles.

2) Other Damages to Property

Beaver use woody and herbaceous vegetation for food and as
building materials. These activities can result in the loss of
commercial timber through cutting or girdling, the destruction of
ornamental or fruit trees, and even depuration of agricultural
crops adjacent to beaver wetlands. In addition, beaver may
damage ditch banks and culverts through burrowing, and in some
instances farm equipment has fallen into beaver bank-tunnels or
ditch-bank dens.

VII. Determination if Substantive Beaver-Caused Socioeconomic
Problems are Occurrin

1) Types and locations of potential problems and factors to
consider and evaluate.

A. Private Lands in Urban or Suburban Areas.

In urban or suburban areas, beaver damage often involves the
girdling or cutting of ornamental trees and shrubs. Their
burrowing under roads or walkways may cause collapse. Beaver-
induced flooding can cause damage to lawns or gardens, basements
or foundations, and roadside ditches or driveway culverts.
Beaver activities can interfere with the functioning of septic
fields or cesspools, and can inhibit stormwater management
facilities. However, many flooding "problems" in urban or
suburban areas are often more cosmetic than truly damaging, in
that many people do not like the conversion of lawns to standing
11swamp" water. Additionally, flooding damage is often limited
only to minor structures located in the floodplain, which could
be moved with relatively little trouble (e.g., woodpiles, dog
houses or kennels, small sheds, etc.). Nevertheless, the
willingness of property owners to accept even minor new pools of
standing water.on their property may not meet with widespread
acceptance. Possible concerns with potential cutting of
ornamental trees or other valuable vegetation, in relation to
either existing beaver colonies or proposed introduced colonies,
may be addressed by educating landowners about damage prevention
methods. Such methods may include enclosing the bottom three
feet of valuable individual trees with heavy wire mesh, hardware
cloth, or galvanized metal. Commercial deer repellents may deter
beavers, with diluted repellent (1:50) painted on the first few
lower feet of a tree trunk. Exclusion fencing of small critical
areas such as driveway culverts, storm drains, or small ponds may
prevent damage.

B. Tax Ditches

The agricultural tax ditch system in Delaware is used to
drain water off agricultural fields within a 24-hour period in
order to prevent crop damage. Tax ditches also help prevent
flooding of highways and road structures, and provide drainage
relief for residential properties. Tax ditches are independent
units of government established by the courts, and are supervised
by tax ditch associations and tax ditch managers.

Beaverdams built in tax ditches can cause surface flooding
of agricultural cropland or commercial timber adjacent or lateral
to beaverdam wetlands. Upstream drainage may also be inhibited,
creating similar problems for agriculture or forestry in the
upstream watershed. Even if surface flooding does not occur,
excessive subsurface wetness may be caused by tax ditch blockage,
lowering crop production lateral to ditches (although higher
water tables in ditches may enhance crop production during

droughts or late summer). Tax ditch blockage by beavers may also
impair the operation of water control structures within the
ditches. Finally, beaver activities may affect ditch-edge access
of vehicles or heavy machinery necessary for crop production or
ditch maintenance and repair.

C. Public Lands - Conservation or Recreation Areas

The promotion of beaver-created wetland habitat on public
conservation or recreation lands is, in a relative sense, easier
to accomplish than on other types of lands. However, beaver
activities on public lands may still create problems needing
remedial action. For example, on Bombay Hook National Wildlife
Refuge, beavers have occasionally plugged water control
structures needed to manage water levels for waterbird habitats
within impoundments, with blockage usually occurring in the
"drawdown" phase of impoundment management. The impacts of
flooding on species or habitat management plans, including
species of special concern and rare or endangered species, should
be considered; many wetlands species will benefit from enhanced
hydroperiods, while others may not. Flooding impacts may also
have unacceptable effects on recreational access or use of the
land (for both consumptive and non-consumptive recreational
activities). Beaver activities and their effects on tax ditches
crossing public lands must also be considered, in terms of needed
ditch functions on both public and private lands, and in
consideration of the tax ditches' adverse environmental impacts
to public lands (for which beavers may serve as remedial agents).

D. Highways, Railways, Airports

The frequency, duration and depth of beaver-induced
floodings on road surfaces, railways, runways, and other
transportation corridors must be considered, particularly in
regard to the extent of threat to public safety. Beaver
activities can also cause unacceptable impacts to transportation
structures such as clogging of culverts, burrowing into
embankments or causeways, or roadbed undermining due to saturated
conditions and erosion.

E. Private Land in Rural Areas (Non-tax ditch)

Many of the beaver-caused problems potentially occurring on
private urban or suburban lands (see Section VII-la) may also
occur on private lands in rural areas. Additionally, flooding
damage or unacceptable cutting or girdling of vegetation may
affect agricultural crops or commercial timber.

2) Prioritization of Concerns if Two or More Types of Problems
are Occurring at One Site

In Section VII-1 above, 5 classes of potential beaver
problems are described: a) private lands in urban or suburban
areas; b) tax ditches and the aglands or other lands influenced

by tax ditch drainage; c) public lands-conservation or recreation
areas; d) highways, railways, airports; e) private lands in rural
areas (non tax-ditch). It is not unusual for a beaver-caused
problem to involve aspects of two or more problem classes. For
example, a beaverdam, may have been constructed on a State
Wildlife Area (SWA) in a tax ditch which has a natural tributary
upstream of the SWA on private lands, and this natural tributary
flows under a public road. Beaverdam flooding on the SWA may be
creating desirable wildlife habitat on the SWA and improving
downstream water quality, but at the same time the elevated water
may: 1) occasionally block access to a SWA maintenance road; 2)
create poor drainage in 3 acres of upstream cropland; 3) cause
minor road floodings of the public road when rainfall exceeds 2"
in 24 hours; and 4) occasionally cause inundation of the lower
end of a dog kennel on private land.

In order to provide some guidance for how to prioritize
concerns when evaluating whether or not substantial beaver-caused
problems exist, which may also help in selection of remedial
actions, the following recommendation is made for beaver-problems
involving two or more classes of problems. We recommend that the
following sequence of concerns be recognized in evaluating
beaver-induced problems, ranked in priority from higher concern
(#l) to lower concern (#4):

1) Highways, railways, airports
2) Tax ditches and the aglands or other lands
influenced by tax ditch drainage
3) Private lands, whether they be urban/suburban
or non-tax ditch rural
4) Public lands - conservation or recreational

This prioritization does not suggest the neglect of any problem
that may be occurring in a lower priority class when two or more
problem types simultaneously occur, but it does provide some
guidance to decision-makers whenever prioritization of problems
may be necessary to make an action decision. Also note that this
recommended sequence does not set priorities for determining how
to balance the positive environmental aspects of beavers with
their potential socioeconomic problems. The recommended
prioritization merely applies to ranking concerns for when
beaver-induced impacts are determined, on a site-specific basis,
to be substantive problems.

3) Integration of Factors to Make a Decision if Substantial
Problems are Occurring and if Remedial Action is Warranted

Section VII-1 identifies 5 classes of potential
socioeconomic problems that beavers may cause, and Section VII-2
recommends a prioritization of the class concerns for when
substantive problems are recognized or identified.
Unfortunately, no simple "cookbook" formulae exist to determine
if and when substantive socioeconomic problems occur to an extent
where remedial action must be taken. Nor are there simple

procedures to follow to weigh positive environmental benefits of
beavers against problems that they might be causing. Each
suspect beaver-problem will have to be evaluated on a site-
specific, case-by-case basis, since each location's setting and
circumstances will be unique. The most critical tool in
determining if a substantive problem really exists will be the
balanced judgment of a trained ecological professional,
knowledgeable about both environmental values and socioeconomic
realities.

In almost all cases, it would be environmentally desirable
from the standpoint of quality wildlife habitat or good water
quality to let beavers remain in an area and go about their
business of being beavers. However, the potential socioeconomic
problems discussed in Section VII-1 may frequently override the
environmental desirability of retaining beavers at certain
locations. It will be important in the decision process to
recognize truly substantive problems and to reject cosmetic or
superficial complaints. Clearly, part of the assessment process
must involve estimation of economic or acreage losses that
beavers may be causing residential areas, agriculture or
silviculture. Estimation of economic costs would also be
involved for the maintenance, repair or modification of
transportation structures if problem-beavers are allowed to
remain. Sometimes the availability of a suitable remedial action
(see Section VIII) can quickly and easily turn a beaver-problem
into a non-problem (while still maintaining the beaver's
environmental benefits), but in other cases the beavers may have
to be removed because the available remedial actions are too
costly or impractical. Finally, one must assess the attitudes of
the local people about the presence of beavers, for both the
beaver's good and bad attributes, because the sentiments and
biases of landowners, neighbors, community associations, tax
ditch managers and others will be crucial to the long-term
success of whatever recommendations and decisions are made.
Public education about beavers and their attributes will be
needed to counter incorrect perspectives or unwarranted biases.
Since the Division of Fish and Wildlife does not have the
authority on private lands (nor on many public lands) to mandate
management either for beaver habitat protection or for taking
remedial actions, the success of a beaver management program must
depend upon mutual understanding and cooperation amongst public
agencies and the private sector.

VIII. Remedial Response Options if a Substantive Beaver-caused
Socioeconomic Problem is Occurring

1. Live-trapping and transfer of problem-beavers.

A. Identification of Potential Release Sites for Live-Trapped
and Transferred Beaver

The identification of potential release sites for live-
trapped and transferred beavers involves several environmental

considerations. Each potential release area will require
evaluations of site-specific criteria. A potential release site
should be reviewed in terms of the support necessary to maintain
a male-and-female pair of transferred adult beavers, plus up to
two generations of their offspring (i.e. kits and yearlings)
simultaneously occupying the site. Additionally, because of both
innate social behaviors and habitat needs, one should not be
surprised if some (or many) relocated beavers extensively wander
away from their release sites; one should also expect that
mortality will be high during these extensive movements or
wanderings.

Criteria for release site selection should include:

1. Acceptance by landowners in the potential floodplain;

2. Suitable on-site habitat capable of supporting beavers,
with attention to hydrological potential and food
supply; release sites with extensive forested areas
adjacent to waterways will provide longer-lived colony
locations than sites where the forested cover is only
a narrow corridor along the watercourse;

3. The release site's potential wetlands edge (i.e. the
predicted edge of standing water in a beaverdam
wetland) should be assessed in terms of proximity to
agricultural fields and vertical relief between
wetlands bottom and agricultural field edge; based
upon the predicted height of water in a beaverdam
wetland (e.g. 5-feet above bottom), estimate extent of
lateral and upstream flooding in relation to adjacent
croplands; eliminate potential release sites having
moderate to high probabilities of creating cropland
flooding problems;

4. Evaluate current land-use patterns and the associated
reliance on tax ditch systems to determine if beaver-
caused flooding in an area would be compatible with
existing land uses, causing only minimal negative impacts;

5. Evaluate potential flooding of highways and roads,
culverts, residential structures and property, etc.;

6. Consider proximity to ornamental vegetation, tree farms,
nurseries, etc. that may be damaged by beaver cuttings;
for concerns with potential vegetation cutting damage
in residential areas, landowners should be educated
about possible damage prevention measures (see Section
VII-lA).

7. Determine if a potential release site (or the
potentially flooded area) has been identified as a
habitat of special concern, in that it contains rare or
endangered plant or animal species or constitutes a

unique biotic association; beavers moving into such
areas may cause hydrological alterations detrimental
(in intermediate ecological timeframes) to extant flora
or fauna; while such impacts would probably not call
for remedial actions for beavers "naturally" colonizing
a site (i.e. moving-in unassisted by man), the
purposeful release or reestablishment by man of beavers
in such valued areas may not be currently desirable,
particularly if alternative release sites having
equally attractive features for beavers are available;
however, it must be kept in mind that when beavers have
become fully reestablished in Delaware (i.e. when they
occupy all naturally available sites not causing
substantive socioeconomic problems), the beavers' final
decision to occupy (or reoccupy) a site will depend
solely on suitable topography, hydrology and vegetation
as perceived by the beavers, not on man-made classifi-
cations of extant biota;

8. Consider the need for beaver sterilization prior to
release to prevent potentially undesirable colonizations
to adjacent but unintended areas.

Generally Desirable Release Sites:

1. Compatible public lands (e.g. state wildlife areas,
state parks, state forests, national wildlife refuges);

2. Private lands having suitable environmental features,
where landowners are cooperative and socioeconomic
problems will be minimal, both for the actual release
site and within the surrounding vicinity in event of
beaver moving off-site.

B. Potential release sites in Delaware

The Division of Fish and Wildlif e maintains updated maps of
potential release sites for problem-beavers, and keeps an
inventory of sites where beavers have been released. The
Division is made aware of potential sites by private landowners,
Division field staff, and other sources. As of July 1991, the
Division of Fish and Wildlife has identified 17 potential release
areas in Delaware for problem-beavers, with 8 areas on state-
owned lands and 9 areas on private land. Each potential release
area could accommodate from 4-12 transferred beavers depending
upon an area's specific characteristics; statewide, these 17 areas
could potentially accommodate an estimated total of 110
transferred beavers.

The transfer and release of beaver in a relocation area
should consider the number of potential suitable sites in an area
which could be occupied by beaver pairs. As much as practical, a
live trap-and-relocate program should consider territorial needs
and behavior of beavers, release of male-and-female pairs,

population age structure, and other social factors important to
colony success. Sexing of beavers can be done in the field (via
presence or absence of baculum), but to make such observations
requires an immobilization device. The best candidate animals
for relocation and successful establishment of new colonies, in
terms of staying on-site at the release areas, are pregnant
females, with the best times for transportation from February
through April. Releasing too many beavers in a relocation area,
or stocking beaver groups having inappropriate sex ratios or age
structures, should be avoided as much as possible.

We believe that the potential release sites identified to
date may represent a substantial fraction of the ultimate number
of potential release sites in the state, so it will become
increasingly harder to find future release sites for transferred
beaver. Because of the flat topography that exists throughout
most of Delaware, beaver activities can cause water to back-up
over extensive areas. While in many ways this helps to promote
positive environmental aspects of beaver activities, it may also
increase potential socioeconomic problems, thus lowering the
number of options for potential release sites. In order to help
insure the successful establishment of transferred beavers,
potential release sites will not be publicized. New potential
release sites or cooperative landowners will be both sought and
welcomed.

Using Delaware's two National Wildlife Refuges (Bombay Hook
and Prime Hook) as potential release sites for problem-beavers
might be possible in certain instances, but these outlets are not
as attractive as one might assume. The U.S. Fish and Wildlife
Service has a policy not to introduce animals of any kind on a
federal refuge without extensive tests of individual animals to
rule out transmission of disease to extant wildlife populations.
Such a precautionary policy has both its advantages and
disadvanatges--in terms of procedures and paperwork needed to
release transferred beavers on the federal refuges, the
bureaucratic hurdles may be too great to achieve expeditious,
economical releases, particularly if alternative release sites
exist.

The alternative of shipping Delaware's problem-beavers for
relocation out-of-state is not viable, since most other states
also now have substantial populations (and their own problems).
In a recent telephone survey conducted by the Delaware Division
of Soil and Water Conservation, all 50 states and several
Canadian provinces were attempted to be contacted to see if
they would accept live-trapped Delaware beavers. The phone
survey was able to contact authoritative personnel in 31 states
and the province of Quebec. Out of the authoritative contacts
that were made, only the state of Idaho was willing to accept
Delaware beavers; Idaho said they could accept 25-50 beavers on a
one-time basis, if Delaware was willing to provide the
appropriate transport care and pay for their shipping. We
probably would not have considered out-of-state transport of

problem-beavers prior to filling all suitable and desirable
relocation sites in Delaware. However, the phone survey does
indicate that once Delaware's release site are exhausted, the
option of out-of-state relocations has very limited potential.

C. Methods of Live Trapping

When beavers are to be removed from an area, the site where
the colony is living should be examined carefully before setting
traps. It is important to look for dams, lodges, bank burrows,
travel canals, and food plots. It is also important to remember
that each trap must be placed to get the quickest result. There
are basically two types of traps that can be legally used for
trapping beaver in Delaware. There are traps that kill the
animal (e.g. leg-hold traps in a drowning set), and there are
traps that will restrain a live animal until the trapper returns
(e.g. Bailey or Hancock live-traps or cable snares).

Live-traps are used to capture beavers alive so that they
can be removed from an area. The most common live-trap is the
Bailey trap. The animal steps onto a trigger pan, and the Bailey
trap closes around the animal like a suitcase. The other live-
trap used in Delaware is the Hancock trap. It is similar to the
Bailey except that only one side of the trap closes while the
other side remains in place. The Hancock trap was designed for
use on steep banks and is easier to use than the Bailey type.
Both of these types of live-traps are fairly expensive, costing a
few hundred dollars per trap.

Another method of live trapping beavers is to use a cable
snare. Cable snares can be effective, practical, time-saving
devices for beaver capture (T.S. Hardisky, pers. comm.). There
are several advantages to using cable snares: good trapping
efficiency; lightweight and inexpensive ($1.00 per snare); cannot
injure trapper or unsuspecting traveler and will not kill
captured beavers; risk of non-target capture is low, and non-
target catches can be released; low susceptibility to theft or
rust. Disadvantages include: heavy tie-down required; cannot be
reused after capture; first-time users require instruction in
their use and types of sets.

D. Methods of Transfer

Once a beaver has been live-trapped, the trap and captured
animal should be carried to an unobstructed area so that the
beaver can be more easily transferred from the trap to a
transport cage. Transport cages were designed and built by
Division of Fish and Wildlife staff to aid in transporting
trapped beavers to release sites. The transport cage was
designed so that when transferring a beaver from a trap to a
cage, the beaver does not need to be handled, and the transfer
can be accomplished by one person if required. This also helps
the trapper, so that he may re-set his traps immediately if
needed, and not have to use the traps themselves as the transport

containers. It must be kept in mind that live-trap and transfer
operations involve some stress on the animals, and that nervous
reactions may result in gnawing on transport cages, sometimes
resulting in chipped or broken teeth. Occasional mortality
should also be expected.

Once a beaver is in the transport cage, it is taken by
vehicle to the release site. Data are collected and recorded at
the release site on a beaver-release data sheet (Appendix 6).
Tagging the beaver with a metal ear tag is the last step prior to
release, The beaver is taken out of the cage with a noose-pole,
and a numbered tag is fastened to the ear (National Band & Tag
Co., Jiffy Style 893, size 3). Beavers may also be marked with
tail tags (cattle ear tags can be used). Tail tags are not as
susceptible to loss as are ear tags, since the tail consists of
thick cartilage (not highly vascularized) under scaly skin.

E, Potential Need and Procedures for Reproductive Control of
Transferred Beavers

At some potential release sites, the fear of beavers
reproducing and having their progeny move off-site to cause
unforeseen problems may be great enough that sterilization of
live-trapped and transferred animals might be considered prior to
their release. The most acceptable methods for induced sterility
include male vasectomy and female oviducal ligation. Testicular
or ovicular castration is not recommended because of associated
behavioral problems. However, because of the expense involved in
doing any surgical procedures, with the need for veterinary
operative and post-operative care, it is doubtful that
surgically-induced sterility will have much practical use.
Additionally, effective chemosterilants are not available for
beavers. It is more probable that if progeny expansion is a
major concern at a release site, and if the problems that might
be associated with progeny movement could not be handled by other
methods, then the release site would probably be delisted as a
release location. If release sites are used where the potential
for future beaver problems is more than minimal, then the need
for extra post-release monitoring and increased responsiveness to
complaints should be recognized.

F. Long-Term Monitoring of Transferred Beavers

Problem-beavers transferred and released at designated
release sites are tagged to allow their future study. Periodic
inspections should be done, probably by wildlife biologists, at
and near the release sites to see if the beavers are successfully
colonizing the site, to determine what types of activities the
beavers are doing, and to see if beavers are causing any
unforeseen problems on-site or off-site.

2. Dispatch of Problem-Beavers

When potential release sites for problem-beavers have been

exhausted, or when manpower, monetary or logistical
considerations do not permit a live-trap and transfer operation,
it may be necessary to dispatch problem-beavers. It is probable
that the killing of problem-beavers will become a more common
solution to beaver problems in Delaware as the options for
release sites become scarcer; if no release sites are available
for problem-beavers, then dispatch becomes the only solution when
structural remedies (see Section VIII-3) are impossible or
impractical.

Dispatch of beaver can be effectively achieved using a leg-
hold trap in a drowning set, where a slide device or angle of the
trap-set prevents reemergence of the captured animal. The
potential for capturing non-target species in leg-hold traps is
low, as long as care is given to making the proper aquatic sets.
Cable snares can also be used for trapping beaver, and any non-
target species which may be caught can usually be released
unharmed from a cable snare set. Beavers live-trapped in a cable
snare could then be dispatched by legally-approved methods. Leg
snares could also be used, but these spring-activated snares are
difficult and time-consuming to use for aquatic drowning sets.
Beavers can also be trapped in a live-trap such as the Bailey or
Hancock, and then dispatched upon retrieval. Killer or conibear
traps of sufficiently large size for beaver capture (e.g. #220 or
#330) are illegal to use in Delaware. Any permitted trapping of
problem-beaver should be done in a humane fashion as discretely
as possible.

Potential personnel who might participate in beaver trapping
and dispatch include Division wildlife biologists or enforcement
officers, private contract trappers authorized by the Division,
private landowners, or private trappers seasonally participating
in a regulated trapping program open to the public.

3. Regulated Trapping Program Open to the Public

Beaver-nuisance problems may become too widespread or
intensive in Delaware to be satisfactorily handled by the
Division of Fish and Wildlife, whether done by Division-
contracted trappers or by staff enforcement officers or wildlife
biologists. Funding availability may limit the effectiveness of
using contracted agents to control beavers, even if the costs of
trapping and dispatch are cost-shared under certain conditions.
For example, trapping and dispatching 100 problem-beavers per
year at a contract cost of $50 per beaver would cost $5000 per
annum. Also, time and availability of even contracted agents may
not be adequate to contend with nuisance problems if they become
too numerous.

In order to contend with beaver problems that may become too
numerous or widespread to be satisfactorily handled on a case-by-
case basis, the Division does have, as a readily available
option, the remedy of a regulated trapping program open to the
general public, which could be used to manage overly abundant

beaver populations. The creation of a beaver trapping program
open to the public, if needed or desirable, would be done via the
Division's regulatory authority and procedures.

Any statewide open trapping season for beavers would be
developed having an annual total statewide harvest goal in mind
(e.g. 150 beaver per year), with the goal achieved via control of
season lengths, harvest limits per trapper, numbers of
participating trappers, gear restrictions, etc. (or various
combinations of these limitations). The types of traps and
trapping methods to be used in a regulated trapping season open
to the public would be the same as discussed in Section VIII-2.
As with any type of open season trapping, traps could not be set
for beavers without prior permission of the landowner. Beaver
harvest could be monitored via a tagging or registration system.

The use of a regulated trapping program open to the public
is probably one of the most cost-effective methods for
controlling undesirably high beaver numbers (in terms of
statewide population densities). Additionally, such a program
offers the public new sources of food and fur, plus new
recreational opportunities. However, public trapping does not
have the level of precision that other approaches offer for
contending with specific beaver-caused problems, nor for
safeguarding the continuance of beaver activities at desirable
sites. There is potential that problem-beavers might be
underharvested and thus not cure certain site-specific problems,
while beavers at non-problem locations, where they're environ-
mentally beneficial, might be overharvested. Thus, total
statewide harvest goals might be achieved, but specific nuisance
.problems might not be eliminated, while environmentally-desirable
activities might be unwantedly terminated.

Nevertheless, an open trapping season would allow private
landowners to take care of their own beaver problems without
having to get a special permit from the Division (which would be
needed during the closed seasons). Additionally, in areas where
beavers are not causing socioeconomic problems, but are subject
to density reductions via an open trapping season, new vacancies
would be created for release (during closed seasons) of problem-
beavers that could be live-trapped and transferred. Since the
economic demand for beaver fur or meat is now very low, it would
not be too surprising if much of the harvest during an open
season focused on problem-beavers.

in the event of undesirable underharvesting or over-
harvesting of beavers in more localized areas, refinements to a
statewide open season could be made by dividing the State into
several geographical zones, each zone potentially having
different open season lengths, total harvest goals, individual
limits per zone, etc. Depending upon the demand for
participating in a beaver trapping program, exclusive trapping
rights might have to be delineated for areas within the zones and
awarded to individuals on a lottery basis, or the total number of

participants within a zone might have to be restricted, perhaps
again using lottery selection. Such fine-tuning of wildlife
harvests are familiar undertakings for the Division.

An additional refinement to a public open trapping season
might be the creation of a "hot spot" program for landowners
having extensive beaver damage problems on their property. Such
landowners would enroll in the program and allow public beaver
trapping on their land only; the names and addresses of all
cooperating landowners would be available to interested trappers.
The number of trappers permitted on lands in a "hot spot" program
would be determined by the landowner in consultation with
Division of Fish and Wildlife biologists, and all trapping
procedures would still have to adhere to the public season dates,
bag limits, prescribed methods, etc.

In event of a beaver population expanding beyond the State's
resource availability to control it, perhaps a combination of a
Division-regulated trapping program open to the public to contend
with statewide or regional density problems, plus a Division-
authorized contract trapper program to contend with site-specific
problems, would yield the most responsive, cost-effective
approach.

An overview of how nearby states (Maryland, New Jersey,
Pennsylvania, New York, Virginia, West Virginia, North Carolina
and Massachusetts) handle open trapping seasons for beaver and
respond to nuisance problems is given in Appendix B.

4. Structural Remedies to Resolve Flooding Problems Caused by
Beavers

Many types of structural remedies have been tried to resolve
socioeconomic problems that may be associated with excessive
flooding or high water levels in beaverdam wetlands. In
situations where beavers must be removed (by trap-and-transfer or
dispatch) and then the flooding problem eliminated, the complete
remedy must also involve the structural removal or breaking-up of
the beaverdam, accomplished by hand, heavy machinery or
explosives. While it is prohibited in Delaware to damage the
nest, den or lair of a game animal, the.alteration of a beaverdam
(whether an active colony is present or not) is not prohibited.
In many cases, however, it is possible to control water levels
with water control structures where beaver ponds are desired,
allowing the beaver to remain. These water control structures
are designed to lower and maintain desired water levels in
existing beaverdam wetlands. An example of a beaverdam water
control pipe is given in Figure 5, and was installed in a
beaverdam located on a State Wildlife Area during the spring of
1991. It is important that the water intake end of a beaver pipe
be submerged deeply enough that all running water noise, and even
surface whirlpools or swirls, be eliminated, since beavers will
go to great lengths to attempt to block any running water that

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Figure 5 Examples of beaver-flow.through pipes using
corrugated flexible sewer pipe and PVC pipe

they can detect. Initial observations indicated the
structure was functioning as desired, but before substantial
monitoring could be done, the system was vandalized.

Most beaverdam water control structures consist of flow-
through pipes of various diameters and configurations that are
designed and installed to stop dammed water from rising above a
desired level during times of normal runoff. Thus, no matter how
high beavers may attempt to build a dam, the water level during
normal runoff periods will not be able to be maintained by
beavers above a human-determined level. Beaverdam water control
structures are not designed to control water levels during spates
(short-lived, si;-oradic, rainfall-induced flooding events). Water
level control during spates is determined by the height of
spillways that beavers may have built into a dam, or by the
actual top of the dam itself, with the entire surface of the dam
top serving as a spillway. Each beaver site will vary, so the
design and installation of beaverdam water control structures
must be site-specific.

There are several considerations that need to be examined
before choosing and installing beaverdam water control
structures. First, the socioeconomic acceptance of installing
the structure must be a paramount consideration. The diameter
and number of flow-through pipes to effectively handle the water
volumes in inundated areas during routine or base flows (in order
to maintain desired levels) must be calculated prior to
installation. The design of the structures should be as
beaverproof" as possible, in that it should be very difficult
for beavers to block the water intake or outflow devices of the
structures. The structures should also blend visually with their
surroundings, and not be excessively visible to invite vandalism.
The installation costs for long-term maintenance and
repair must also be considered, as well as designation of the
agencies or personnel responsible for these activities.

5. Choosing a Remedial Response for a Substantive Beaver-
Caused Problem

As with determining if a substantive beaver-caused problem
exists in the first place (see Section VII-3), there are no
simple "cookbook" formulae for determining the type of remedy to
use to address substantive problems. While a purpose of a
possible regulated trapping season open to the public is to help
reduce beaver regional population densities to levels in which
nuisance problems become more managable, substantive nuisance
problems will still occur that must be addressed on a case-by-
case basis. The selection of a remedy for substantive problems
must be evaluated on a site-specific basis. The live-trap and
transfer option may be the most preferred, but is heavily
dependent upon staff availability and coordination on short
notice, plus the availability of suitable release sites.
Structural remedies whose implementation would allow beavers to
remain on-site and not cause socioeconomic problems are sometimes

too costly to be practical, or from an engineering standpoint may
be impossible, or from the standpoint of commitment to long-term
maintenance and repair may be impractical. Dispatch of problem-
beavers is the quickest and least expensive remedy, but this
option eliminates the positive environmental benefits of active
beaverdam wetlands, and in some cases may cause adverse human
reactions or social problems.

6. Criteria for Evaluating the Environmental Quality or
Importance of Existing Beaverdam Wetlands.

The expense and effort associated with various remedial
options varies widely, ranging from relatively inexpensive on-
site dispatch done by landowners or contract trappers, to more
expensive 1,ive-trap and transfer operations, to more costly
installation and maintenance of structural remedies. The factor
of cost effectiveness should also be built into an evaluative
process for determining how to deal with substantive beaver-
caused problems, since resource management funds are limited and
must be wisely spent. It makes practical sense that in deciding
how to spend limited funds for wisely managing beaver
populations, we should not invest heavily in remedial actions
(for substantive problems) in existing beaverdam wetlands where
the environmental values or benefits of a given wetland are
relatively lower than in another beaverdam wetland having greater
environmental values and benefits. Conversely, when given
limited funds for beaver management, we might spend our resources
for the more costly structural remedies (to maintain existing
beaverdam wetlands) for only those wetlands having higher
environmental values and benefits.

In order to help evaluate the level of environmental values
and benefits of existing beaverdam wetlands, the following
factors should be considered for existing beaverdam wetlands:

A. What is the expected longevity of the beaverdam wetland (e.g.
number of years) before one would predict that the colony will
have to abandon the site? At current water levels, how much
longer might it be expected that herbaceous or woody vegetation
will remain adequate to meet the colony's needs? Can water
levels be raised in the future by the beavers (in order to
provide access to new food sources) without causing substantive
socioeconomic problems? If water levels can be raised, how many
more years of colony occupancy might be predicted?

B. What are the known or suspected site-specific values of the
existing beaverdam wetland for wildlife habitat? Is there
knowledge or evidence that the site is valuable for waterfowl
production, feeding or resting, or that it's valuable habitat for
other waterbirds or passerine species? Does it have abundant or
diverse populations of fishes, amphibians or reptiles? Are
muskrat lodges evident, or is there evidence of raccoon or otter
use? Are endangered, threatened or rare species present?

C. Does the existing beaverdam wetland appear to be located at a
site where it would be providing substantial water quality
benefits, in terms of sediment retention or dissolved nutrient
filtration? For example, beaverdam wetlands immediately upstream
from the headwaters of millponds, or those that receive upland
runoff fron extensive cropland acreage, or those that receive
urban runoff from watersheds lacking good stormwater management
controls, all have the potential to be important landscape
features for maintaining or improving water quality.

D. The size (acreage) of a beaverdam wetland should be
considered. In general, the larger the area affected by
beaverdam inundation, the more valuable the site, since greater
amounts of environmental benefits would be associated with larger
sites (in comparison to smaller sites).

E. Will future water supply to the existing beaverdam wetland be
adequate to meet the colony's needs? If not, then beaver will
abandon the site. If it's known that man's future plans for
water supplies at a site will unavoidably cause excessive water
extraction or diversion at expense of the colony's water needs,
then the site's potential longevity will be compromised.

IX* Identification of Types of Action Costs Associated with
Implementin a Beaver Management Plan.

1) Cost of determining or resolving if a substantive beaver-
caused problem is occurring and warrants remedy.

2) Cost of determining the type of remedy to use to resolve
a substantive beaver-caused problem.

3) Implementing the remedies
a) Live trap/transfer

Trapping costs
Transportation costs
Pre-release and release procedural costs
Long-term monitoring costs

b) Dispatch

. Trapping costs
. Disposal costs

c) Structural Measures

Costs of determining the type of structure
to use
Engineering design costs
Structural material costs
Installation costs
Regulatory permit costs (if needed)
Long-term maintenance and repair costs

X. Preferred Participation and Responsibilities of Agencies and
Personnel in a Beaver Management Plan

The Division of Fish and Wildlife is recommending the
following participatory roles of agencies and personnel in
implementing the Beaver management Plan. We have recommended the
participation of agencies or personnel in context of 5 classes of
beaver-caused problems and 7 types of management decisions or
actions:

Types of Beaver-caused Problems:

1) Private urban/suburban residential
2) Tax ditches and the aglands or other lands
influenced by tax ditch drainage
3) Public lands-conservation or recreation
4) Highways, railways, airports
5) Rural private lands (non-tax ditch)

Types of Management Decisions or Actions:

1) Who has final authority to determine if there is a
substantive beaver-caused problem?
2) Who finally determines the desirable action to be
taken if a substantive problem exists?
3) Who implements action if the remedy is to live-trap
and transfer?
4) Who monitors long-term for transplanted beaver?
5) Who implements action if the remedy is dispatch?
6) Who implements action if the remedy is a structural
solution?
7) Who manages long-term for maintenance and repair of
structural remedies?

In order to help delineate who takes what action based on
the types of problem that may be occurring, we have identified 13
categories of potential plan participants:

1) Division of Fish and Wildlife (DNREC) biologist
2) Division of Fish and Wildlife (DNREC) enforcement
officer
3) Division of Fish and Wildlife (DNREC) biologist,
whose activities are cost-shared with the landowner
4) Division of Fish and Wildlife (DNREC) enforcement
officer, whose activities are cost-shared with the
landowner
5) Landowner or designated lessee
6) Tax ditch manager
7) Other State of Delaware employees (e.g., Division
of Soil and Water Conservation field technicians;
Division of Water Resources wetlands staff;
Division of Parks and Recreation naturalists;
State Foresters; Division of Highways engineers;
etc.)

8) U.S. Soil Conservation Service engineer, biologist
or field technician
9) Conservation District engineer or field technician
(New Castle Conservation District; Kent Conserva-
tion District; or Sussex Conservation District)
10) Contract trapper authorized under permit from the
Division of Fish and Wildlife
11) Contract trapper authorized under permit from the
Division of Fish and Wildlife, whose activities are
cost-shared with the landowner
12) Private engineer or contractor working at the
landowner's expense
13) No action - no personnel

The recommended participation of these agencies or
personnel, in context of the type and location of beaver-caused
problems, is given in matrix format in Table 1. For most of the
individual management decisions and actions in Table 1, more than
a single party is indicated, reflecting the complexity and
diversity of affected parties in making and taking management
actions. Table 1 also provides a recommended hierarchy for
decision-making and action-taking, indicating which agency or
personnel has the final responsibility when two (or more) parties
want to make the same final decisions or perform the same
management actions. However, no matter who is recommended to
take final responsibility for a management decision or action,
the advisory input of all interested parties must be seriously
considered.

On Bombay Hook or Prime Hook National Wildlife Refuges,
which are owned and managed by the U. S. Fish and Wildlife
Service, the management of beavers and their habitats will be the
responsibility of federal refuge personnel. Management
activities should conform to the Service's refuge management
plans; beaver trapping or other forms of harvest or capture will
be subject to all pertinent State laws and regulations. When
beavers living on the federal refuges cause substantive
socioeconomic problems off the refuges, the evaluation and
resolution of problems will be a cooperative undertaking
involving both federal refuge personnel and State wildlife
biologists.

Cost-share programs between service agencies and the parties
affected by substantive beaver-caused problems are recommended to
be developed for the following activities:

a. Determination if a substantive problem really exists and
for selecting a remedial course of action.

b. For live-trap/transfer or dispatch remedies.

C. For design, materials and installation of structural
remedies.

BEAVER MANAGEMENT PLAN PARTICIPATION

Table 1. Determination of Responsible Parties for Management Decisions and Actions

TYPE OF IlWh- IWho lWho implementsl Who monitors lWho implements1who implementsl Who manages I
Ildetermines Idetermines laction if it'sl long-term forlaction if it'slaction if it'sl long-term forl
BEAVER Ilif there is Ithe needed Ilive-trap and Itransplanted Idispatch? Istructural? Istructural I
Ila problem? Iaction Itransfer? Ibeaver? I I Imaintenance I
PROBLEM 11 1to take? and repair? I
-11-1-1 1

Private

Urban
Suburban 11 1/5/9/7 1 1/9/7/5 13-1/10/4/3/2/1 1 1/13 11/10/4/3/5 1 9/12/8/3/5 1 9/3/12/5 1
Residential

Tax Ditch

Associated 1/6/5/9/7/8 11/6/5/9/7 111/10/4/3/2/1 1 1/13 111/10/4/3/6/5 7/9/8/6/5 9/6/7/8/5
Aglands

Conservationli I I I I
or 11 1 1 1 1
Recreationalll 1/5/7/9 1 1/7/5/9 1 10/2/1 1/13 10/2/1 1/7/9/8/12 1/7/9/12
Public Landsil

IV.

Highways
Railroads 7/l/9/8 1 1/7/9 111/10/4/3/2/1 1 1/13 111/10/4/3/2/1 1 7/9/8/12/5 1 7/9/12/5 1
Airports

Rural
Private Landli
(Non-Tax 1/5/9/7/8 1 1/9/7/5 111/10/4/3/2/1 1 1/13 11/10/4/3/5 1 9/12/8/3/5 1 9/3/12/5
Ditch)

KEY RESPONSIBILITY HIERARCHY

1. F & W Biologist A/B/C/etc.
2. P & W Enforcement Officer
3. F & W Biologist/Cost Share with Landowner A - FINAL AUTHORITY
4. F & W Enforcement Officer/Cost Share with Landowner B - 1st ADVISORY INPUT
5. Landowner/Lessee C - 2nd ADVSORY INPUr
6. Tax Ditch Manager etc.
7. Other State Employee (e.g. Hwy; Forestry; Soil & Water;
Parks & Rec; Wetlands)
8. U.S. Soil Conservation Service PROBLEM PRIORITIZATION
9. Conservation Districts
10. Authorized Contract Trapper at DFW Expense (For when 2 or more types
11. Authorized Contract Trapper/Cost Share with Landowner or Agency of beaver problem are
12. Private Contractor/Engineer at Landowner's Expense occuring at one site)
13. No Action

IV > II > I - V > III
41

d. For long-term maintenance and repair of structural remedies.

For some activities, the development of a cost-share
approach may require legislative action, while for other
activities cost-shared approaches may be implemented by
regulatory or other programmatic means. Some services that are
now performed gratis by public agencies to assist private
landowners, and which are not legislatively mandated to be
performed, may be suitable candidates for future cost-share
agreements. The experience and expertise of Delaware's three
Conservation Districts in establishing cost-share programs would
be invaluable to address beaver-caused problems.

XI. Listing of management Options to Manage Beaver-Abandoned
Beaverdam Wetlands.

1. No action alternative--let unmanaged succession occur.

2. Destroy beaverdams to accelerate return to low water
levels and channelized flow.

3. Maintain higher, desired water levels by replacing
beaverdams with low-level earthen levees, and manage
water heights with water control structures.

XII. Public Education and Beavers

A major effort in implementing a Beaver Management Plan is
to educate the public about the beneficial environmental
attributes of beavers and their activities. With the current
emphasis on protecting and conserving freshwater wetlands at the
national, state and local levels, it is important to promote
public understanding about the high environmental values and
important functions of beaverdam wetlands. An ultimate goal is
to make the public more tolerant of the presence of beavers. A
reduced or condensed version of this plan should be prepared,
targeted for distribution (on an as-needed basis) to landowners,
the general public, and to non-technical agency personnel,
decision-and-policy makers, and elected government officials.
Outreach efforts such as newspaper and magazine articles, and
presentations to organized groups, are needed to convey the
message. Through education, the public can become proponents of
beavers and the habitat that they provide, helping to promote and
protect the overall wetlands resource.

XIII. Proposed Immediate Action-Steps to Implement the Plan

The following 7 actions are proposed to be initiated as soon
as possible in order to start to implement the Plan. Of course,
these proposed actions are subject to potential unforeseen
limitations of staff, time, funds, etc. The following are not

listed in any order of priorities; we should try to simultaneously
move forward with all 7 actions.

1) In order to lessen beaver nuisance complaints, particularly
in areas or regions where beaver densities have become
intolerably excessive, the Division of Fish and Wildlife will
institute a regulated, controlled beaver trapping season open to
the public. In order to avoid overharvesting beavers, the
initial harvest goals will be conservatively set, with
participation limited only to licensed trappers using prescribed
methods during established seasons in specific zones. The
harvest will be carefully monitored as it occurs, with a
requirement that all pelts be tagged within a limited time period
after capture.

Because of the currently low monetary value of beaver pelts
(about $6 per Delaware pelt), and the hard work that beaver
trapping involves, it remains to be seen if the level of trapper
participation in Delaware (during a zoned open season) will be
sufficient to satisfactorily reduce excessive beaver densities
and their nuisance problems. The first few years of having an
open season would be an evaluative period to see if the nuisance
problems can be reduced to a more tolerable level.

2) Establish/identify a dependable source of Division of Fish
and Wildlife funding (e.g. $5,000 per year) to pay for contract
trapping of problem-beavers. Such efforts will be needed to
contend with beaver nuisance problems (via dispatch or live-trap
and transfer) which may newly arise during the closed season; or
which were not (or would not be) satisfactorily eliminated during
a zoned open season; or for which no landowner wants or is able
to undertake proper corrective action; or in cases where no
"responsible" landowner can be identified.

3) In order to best implement the technical aspects of the
Plan's recommendations for dealing with regional problem
densities or site-specific problem colonies, and for promoting
the environmental benefits of beaver activities, designate which
Division of Fish and Wildlife biologist(s) will have the
responsibilities for the following actions, and provide (or seek)
adequate funds or other support necessary for satisfactory
performance:

a) Design, implement, monitor and analyze controlled
harvests by the public during zoned open seasons.
Enforcement needs during open seasons will be handled by
Division E01s.

b) Make technical determinations, on public or private lands
on a statewide basis, and in consultation with
appropriate parties, whether or not a beaver complaint is
a substantive problem needing remedial action. Because
of the environmental benefits provided by beavers, site-
specific technical evaluation is warranted before

deciding that a beaver complaint received from a
landowner (or other party) is substantive and needs
remedy.

c) Make technical determinations and recommendations, on
public or private lands on a statewide basis, and in
consultation with appropriate parties, about the best
type of remedial action to be taken when action is
needed. Because of the environmental benefits provided
by beavers, case-specific technical evaluation is
warranted when selecting a remedial option, to see if it
is desirable and practical to take structural corrective
actions which will still allow the beavers to remain, or
to see if the situation presents an opportunity to help
establish or expand beaver populations at desired and
suitable locations elsewhere (i.e. live-trap and
transfer); if neither approach is desirable, practical or
available for a substantive problem, then dispatch
remedies must be recommended.

d) In order to further promote the distribution or recovery
of beavers in Delaware in areas or regions of the State
where desired sustainable populations have not yet been
achieved, and where the environmental benefits of beavers
have not yet been optimally realized, continue a program
which solicits, evaluates and inventories potential
release sites for the potential relocation of problem-
beavers caught elsewhere.

e) Coordinate (or in some special cases supervise or
perform) tagging of transferred beavers and gathering of
other technical data at the release sites.

f) Perform casual monitoring at the release sites of the
population and activities of trap-and-transferred
beavers; if new research funds could be found, it may be
desirable to undertake a more intensive study of beaver
responses and activities at a few selected release sites.

g) Help to coordinate (or in some special cases help to
supervise or perform) the planning, design or
installation of structural remedies.

h) Contribute to and help to maintain, at a centralized
Division location, any maps, inventories and detailed
records about existing beaverdam sites and their
populations, trap-and-transferred beavers and their
release sites, candidate release sites, etc.

4) Using the environmental criteria developed in the Plan,
attempt to determine and classify the environmental "quality" or
"importance" of each existing beaverdam wetland in the State.
This could be of value in determining, on a case-by-case basis,
how much effort or resources should be put into structural or

monetary compensation remedies for contending with a substantive
socioeconomic problem caused by a beaverdam wetland. If a
specific beaverdam wetland causing a substantive problem is
determined to be of relatively lower value, then less expensive
dispatch or trap-and-transfer remedies might be used, whereas a
relatively higher value beaverdam wetland causing a substantive
problem might warrant the greater expense of structural remedies.

A precautionary note about the advanced application of this
quality" or "importance" criteria is that we're dealing with at
least 126 potential evaluation sites statewide, which would
require field (ground) and often aerial assessments, a
logistically cost and labor intensive undertaking. The proposed
evaluation as an advance undertaking might not be worth the
effort, since we do not anticipate that.all 126 existing sites
will eventually lead to socioeconomic problems (most probably
won't). It might be wisest and most cost effective to apply the
"quality" or "importance" criteria only on an "as needed" basis,
in response to having to evaluate (in terms of cost
effectiveness) what to do about individual sites when (and if)
they become problematic.

5) Perform longer-term evaluations (e.g. over several months) of
the effectiveness and durability of various water control devices
(i.e. "beaver baffles" or "beaver pipes") for preventing
excessive water heights in beaverdam wetlands during longer-term
period of baseflow. We may also want to design and evaluate
various water control structures intended to reduce maximum water
heights in beaverdam wetlands during shorter-term storm flows or
spates. For devices or structures that are proven to be
.satisfactory, or which have a high probability of success, we
should install a few as demonstration projects on the properties
of cooperative private landowners.

6) Working with the Division of Soil and Water Conservation and
the Conservation Districts, establish cost-share programs for
those Plan activities which the Department and Districts both
agree are desirable and suitable for the cost-share approach.

7) Prepare and make available for public distribution a 4-6 page
information pamphlet about beavers and their activities. This is
primarily intended to be a hand-out for landowners or people
having beaver problems, focusing on beaver biology and ecology,
their environmental benefits, their socioeconomic problems,
remedies that are possible to alleviate problems, how and from
whom to get further information or help, etc.

XIV. Pertinent References

Allen, A.W. 1982. Habitat Suitability Index Models: Beaver.
FWS/OBS-82/10.30. U.S. Fish and Wildlife Service. 20 pp.

Bailey, V. 1927. Beaver Habits and Experiments in Beaver
Culture. Technical Bulletin No. 21., Bureau of
Biological Survey, Washington, D.C.

Bonwill, H. A. and Owners, B. H. 1939. The Return of a Native.
The Natural History Society of Maryland, Volume X, No. 4.

Bradt, G. 1938. A study of beaver colonies in Michigan. J.
Mammal. 19:139-162.

Brenner, J. F. 1962. Foods consumed by beavers in Crawford
County, Pennsylvania. J. Wildl. Manage. 26(l):104-107

Choate, J. S. 1973. Wildlife resources of the St. John River
basin, New Brunswick. St. John River Basin Board, Dept.
Natural Resources, Fredericton, N.B.

Denney, N. R. 1952. A summary of North American Beaver
Management (1946-1948). Colorado Game and Fish Department,
Report 28.

Hilfiker, E.L. 1991. Beavers: Water, Wildlife and Histor
Windswept Press, IiTtEerlaken, NY. 198 pp.

Hill, E. P. 19e2. Beaver. In J. A. Chapman and G. A.
Feldhamer, eds. Wild Mammals of North America:
Biology, Management, Economics. John Hopkins Univ. Press,
Baltimore, Md. pp. 256-281.

Jenkins, S. H. 1981. Problems, progress and prospects in
studies of food selection of beavers. In J. A. Chapman and
D. Purshey, eds. Worldwide Furbearer Conf. Proc., Vol I,
pp. 559-579.

Larmire, A. J. Jr.. 1963. Control device for problem beavers.
J. Wildl. Manage. 27(3):471-476.

McDowell, D. M. and R. J. Naiman. 1986. Structure and function
of a benthic invertebrate stream community as influenced by
beaver (Castor canadensis). Oecologia 68:481-489.

Naiman, R. J. and J. M. Melillo. 1984. Nitrogen budget of a
subarctic stream altered by beaver (Castor canadensis).
Oecologia 62:150-155.

Naiman, R. J., J. M. Melillo, and J. E. Hobbie. 1986.
Ecosystem alteration of boreal forest streams by beaver
(Castor canadensis). Ecol 67:1254-1269.

Naiman, R. J., J. M. Melillo, M. A. Lock, T. E. Ford, and S. R.
Reice. In press. Longitudinal patterns of ecosystems
processes and community structure in a subarctic river
continuum. Ecology

Naiman, R. J., C. A. Johnson, and J. C. Kelley. 1988.
Alteration of North American streams by beaver. BioScience
38(11):753-767.

Renouf, R. N. 1970. Waterfowl production on beaver ponds in New
Brunswick. M. S. theses, Univ. of New Brunswick,
Fredericton, N. B. 66 pp.

Ryden, H. 1989. Lily Pond: Four Years with a Family of Beavers.
William Morrow Co., NY. 156 pp.

Whitman, W. R. 1987. Estimating black duck production on beaver
ponds in the Maritimes, 1976-77. In A. J. Erskine (ed.),
Waterfowl Breeding Population Surveys, Atlantic Provinces.
Canadian Wildlife Service, Occasional Paper No. 6.

Williams, R. M. 1965. Beaver habitat and management. Idaho
Wild. Res. 17(4):3-7.

XV. Appendices (Contents)

1. Delaware Division of Fish and Wildlife Management
Philosophy (Appendix 1)

2. Title 7, Chapter 7, Section 701--Regulations and
Prohibitions Concerning Game and Fish (Appendix 2)

3. Descriptions of selected beaverdam-wetlands habitats in
Delaware.

a. Garrisons Lake (Appendix 3)

b. Paradise Alley (Appendix 4)

c. Masseys Pond (Appendix 5)

4. Beaver-Release Data Sheet (Appendix 6)

5. List of Agencies/organizations who have reviewed the
Delaware Beaver Management Plan (Appendix 7)

6. An Overview of Beaver Trapping Seasons and Control
Programs in Nearby States (Appendix 8)

7. Written Comments About the Plan Received from Other
State Agencies, Federal Agencies, Private Environmental
Groups, or the Public; Public Meeting (Appendix 9)

8. Active Participants in the Development of Delaware's
Beaver Management Plan - plan research and preparation,
technical advice and consultation, or plan review and
comments (Appendix 10).

Appendix 1

Delaware Division of Fish and Wildlife
Management Philosophy

The Delaware Division of Fish and Wildlife was formed to
protect and conserve Delaware's wildlife resources (Section 8005
of Title 29). To fulfill this objective, management principles
were formed to serve as a conceptual basis for Statewide and
Regional Wildlife Management Plans. It is our goal to perpetuate
the natural diversity of indigenous plant and animal communities,
and when possible to restore viable populations of extirpated
species. We recognize that man is an integral component of the
ecosystem and has a significant impact on plant and animal
communities. It is this ability, to determine the fate of our
natural resources, that encumbers upon us the role of stewards.
The Division will assume this responsibility by applying sound
management practices based on the best available biological data.

The Division's first responsibility is to Delaware's
wildlife resources. All species have an intrinsic value and we
must strive to develop and apply the necessary knowledge to
assure their survival through responsible habitat management. We
will encourage, manage for and support the wise use of our
wildlife resources as long as their viability is not jeopardized.
Good quality habitat is essential for wildlife survival. A
dynamic balance exists between plant and animal communities;
changes to either may upset this relationship causing
repercussions throughout the ecosystem. A community with great
diversity of plants and animals is more stable and therefore more
desirable. Our approach will be to manage ecosystems, to
maximize plant and animal diversity and thus increase stability.

Our second responsibility is to manage our wildlife
resources for recreational enjoyment, economic benefit and
scientific instruction. We are committed to the concept of
multiple use management of our natural resources provided the
activity does not harm the resource or infringe upon the rights
of others. Conserving our wildlife resources to provide both
consumptive and nonconsumptive use requires careful planning and
the application of prudent management policies.

The following concepts form the basis of our decision-making
philosophy used to meet the responsibilities with which we are
charged:

Philosophical Tenants for Managing Delaware's Wildlife Resources

1. We are committed to managing ecosystems. We will recommend
no action that threatens the viability of any species or
population because this would effect the stability of the whole
system. Exotic and pest species will not be given equal

consideration with native species. Their relationship to the
ecosystem will be evaluated for adverse effects on native
wildlife populations and human and health safety.

2. We will manage wildlife species as viable, self supporting
and free ranging populations. Consideration will be given to all
species in order to maintain diversity and therefore stability
and to maximize the variety of human experience.

3. Restoring native extirpated species is a desirable objective
provided their reintroduction does not adversely effect human
health and safety.

4. Land acquisition is desirable and necessary to preserve
ecosystem diversity and recreational opportunities. However, the
lands purchased will represent a complete ecological community
without privately owned inholdings or represent an expansion of
an existing Wildlife Area.

5. We will consider both consumptive and nonconsumptive uses in
our planning processes and oppose competitive uses that are
detrimental to wildlife populations or habitats. Competitive
land uses are those that effect the welfare of wildlife because
they alter or destroy wildlife habitat, even though the users may
have no conscious intent to preempt wildlife habitat per se (e.g.
timber harvesting, mining, ditching, human and agricultural waste
disposal, and the spread of urban areas). Note: Timber
harvesting and some other economically-driven land alterations
may often be compatible with, or even enhancing to, wildlife
populations and their habitats, if these activities follow Best
Management Practices (BMP's) which satisfactorily consider and
address wildlife concerns.

6. Population and habitat manipulations are acceptable
management tools provided the viability of a species or the
integrity of an ecosystem is not threatened.

7. We recognize hunting and trapping as legitimate management
tools and recreational pursuits. We will strive to meet the
demands for hunting and trapping as long as species viability is
not jeopardized.

8. We recognize that some competitive land uses are desirable to
human well being; we will mitigate for uses beyond our control
and try to educate competitive users of the trade-offs.

9. Fulfilling our goals requires public support. We will
attempt to educate people to wildlife benefits and instill a
sense of responsibility towards the resource.

10. We recognize that most wildlife habitat is privately owned.
We will develop a landowner wildlife habitat assistance program
and strive to encourage landowners to expand hunting access to
their property.

APPENDIX 2

TITLE 7

CHAPTER 7. REGULATIONS AND PROHIBITIONS

CONCERNING GAME AND FISH

Subchapter I. General Provisions

S 701. Game Animals.
The following shall be considered game animals: Mink,
snapping turtle, raccoon, opossum, gray squirrel, otter, muskrat,
red fox, hare, rabbit, frog, deer, and beaver. The Bryant fox-
quirrel, otherwise known as the "Sciurus niger branti," shall be
protected wildlife.
s

REGULATION 17. SEASONS.

Section 1. Protected Wildlife.

It shall be unlawful to hunt, sell, ship or possess an
species of protected wildlife except as permitted by law.-

Section 2. Beaver.

There shall be no season during which beaver may be hunted,
possessed, shipped or sold, except landowners or their agents may
.trap, possess and sell beavers causing damage on their property
with a valid permit from the Division.

Appendix 3

Garrisons Lake Observed: 8/24/90

Observers: Terri Fabean
Roger J,.*Wolfe
Randall V. Cole

The site is located at the headwaters of Garrisons Lake
(Kent County) approximately 20 feet upstream of the train trestle
culvert. The dam is 51 feet across and 1.5-2 feet in height.
This colony appears to have been abandoned, the dam having been
there approximately 5 to 10 years (Tom Whittendale and Cathy
Martin, pers. comm.). The dam is partially intact with a steady
flow of water coming through open sections. The water is 4-1/2
feet deep above the dam and 2-1/2 feet deep below. Signs of
previous beaver activity include tree girdling and cutting, but
there appears to be no beaver activity at this time. Forest
composition on the south lateral side of the impoundment is 85%
beech, while forest composition on the north lateral side is a
diverse mixture of northern red oak, willow oak, maples and black
gum. Sixty-five percent of the flooded surface area is vegetated
(vegetation species listed below), while thirty-five percent of
the impounded surface is open water. Numerous dead snags are
present through the pond. The depth of the channel within the
impounded area is approximately 4.5-6 feet, while the depth of
water in vegetated areas is 1-2 feet.

Vegetation Observed

Smartweed (Polygonacea)
Spatterdock (Nuphar luteum)
Duckweed (Lemnaceae)
Cardinal-flower (Lobelia cardinalis)
Arrow Arum (Peltandra virginica)
Cattail (Typha latifolia)
Primrose willow (Primulaceae)
Water willow (Decodon verticillatus)

Birds

Green-backed heron (Butorides striatus)
Woodduck (Aix sponsa)
Snowy egret (Egretta thula)
Double-Crested Cormorant (Phalacrocorax auritus)
Kingfisher (Megaceryle alcyon)
Great Blue Heron (Ardea herodias)
Red-Shouldered Hawk (Buteo lineatus)

Trees

Red maple (Acer rubrum)
Willow Oak (auer-cus phellos)
Black gum (Nyssa sylvatica)
Beech (Fagus grandifolia)
Northern rea oak (Quercus rubrum)
magnolia (Magnolia virginiana)
Blackjack oak (Quercus velu:Fina)

Appendix 4

Paradise Alley Surveyed: 8/28/90

Observers: Terri Fabean
Randall V. Cole

This dam is located off Paradise Alley Road (Kent County),
1/2 mile south of the railroad tracks, in a large culvert under a
-train trestle. The dam is intact with a steady flow of water
coming through the middle. The dam is 31 feet across and 4-4.5
feet in height. The water above the dam is 4-4.5 feet deep in
the channel, tapering to shallow depths at the edges. Directly
below the dam is a pool of water 2-5 feet in depth, shallowing-
out downstream to a small channel.

Signs of previous beaver activity include tree girdling and
cutting. A beaver lodge is located upstream of the dam in the
center of the impounded area. The lodge was built on an
overturned tree. There appears to be no fresh sign of beaver
activity at this time, but beaver scat specimens were found.

Forest composition lateral to and along the margin of the
impounded area consisted of a mixture of species including: red
maple (Acer rubrum), willow oak (Quercus phellos), river birch
(Betula nigra), sweet gum (Liquidambar stryaciflua), black cherry
(Prunus serotina), black gum (Nyssa sylvatica), and blackjack oak
Ouercus marilandica). Approximately 45% of the pond center is
vegetated with a variety of species including: duckweed, water
willow, buttonbush, sweet pepperbush, and lizard tail. Coontail
was also present as a submergent. The amount of open pond water
was 35%, and about 20% of the ponded area has dead snags.
Waterbirds present included kingfisher, great blue heron, and
wood duck. Frogs, toads, and a five-line skink were also present
at the time of survey.

Appendix 5

Masseys Pond Observed: 8/30/90

Observers: Terri Fabean
Roger J. Wolfe
Shawn Shotzberger

There is no present dam at this Kent County site, but beaver
appear to be using the pond for food sources and living area.
Two lodges were located upstream of the pond. One is on the bank
of Jim Short's property, which is on the pond's south side in the
lower headwaters. The other lodge is approximately 25m upstream
on the same side, but at a location narrowed into a stream.

Forest composition along the pond edges consists of red
maple, northern red oak, willow oak, black willow, speckled alder
(Alnus rugosa), tulip poplar (Liriodendron tulipifera), and black
o-ak.T'he pond surface consisted of open water with no emergent
vegetation. The pond headwaters were 75% vegetated, with 25%
open water having a 4-5 feet deep channel. Vegetation consisted
of an abundant amount of water willow, with a mixture of
spatterdock (Nuphar luteum), arrow head (Sagittaria latifolia),
jewelweed (Impatiens capensis), smartweed (Polygonum punctatum),
pickerelweed (Pontedria cordata), cardinal flower (Lobelia
cardinalis), and buttonbush (Ce2halanthus occidentalis). Dead
snags were present in the stream section of the pond. The area
upstream appeared to be flooded at-one time, but the water level
was down at the time of survey. There were previous signs of
beaver activity such as tree girdling and cutting.

Appendix 6

BEAVER RELEASE DATA SHEET

TAG NO.

STREAM AND LOCATION WHERE TRAPPED:

TRAPPER:

DATE TRAPPED:

STREAM AND LOCATION WHERE RELOCATED:

DATE RELEASED:

AGE:

SEX:

WEIGHT:

NOTES:

Appendix 7

List of Agencies/organizations Who Have Reviewed the
Delaware Beaver Management Plan

Delaware Division of Fish and Wildlife (DNREC)
- Wildlife Section
- Enforcement Section
- Mosquito Control Section
-Fisheries Section

Advisory Council on Fish and Game

Delaware Division of Soil and Water Conservation (DNREC)
- Drainage Section
- Conservation District Operations
- Delaware Coastal Management Program

Delaware Division of Water Resources (DNREC)
- Wetlands and Aquatic Protection Branch
- Watershed Assessment Branch

Delaware Division of Parks and Recreation (DNREC)
- Technical Services Section
- Delaware Natural Heritage Inventory

Delaware Department of Agriculture
- Forestry Section
- Aglands Preservation Section

Delaware Department of Transportation
- Division of Highways

New Castle Conservation District

Kent Conservation District

Sussex Conservation District

U.S. Soil Conservation Service (Dover)

U.S. Agricultural Stabilization and Conservation Service (Dover)

U.S. Fish and Wildlife Service
- Bombay Hook NWR
- Prime Hook NWR

Appendix 8

OVERVIEW OF BEAVER TRAPPING SEASONS AND
CONTROL PROGRAMS IN NEARBY STATES

MARYLAND

As of now, the Wildlife Administration responds to beaver
complaint calls. Their methods are:

1. The sites are reviewed and technical advice is offered to the
landowner.
2. Trapping beaver on a landowner's property is postponed (if
- possible) until the trapping season is open.
3. If a landowner does not want to personally take care of a.
problem, he can call a licensed trapper to take care of the
matter (at a fee).
4. Staff will often remove beaver themselves (District biologists
or other staff).

Open Trapping Season

January 1 - March 15 Bag Limit = 5-15 per year depending on
county

PENNSYLVANIA

If a landowner has a beaver problem, he can take care of the
problem himself without a permit.

If a landowner does not want to personally take care of a
problem, he can call a damage control officer.

In the northeastern part of the state, beaver harvest was
approximately 400 animals (60% done by landowners).

Open Trapping Seasons

lst Season (Recreation) December 15 - January 15
2nd Season (Fur) March 1 - March 23

The annual bag limit is different throughout the state. It ranges
from 6 to 40 per year depending on geographic location.

If the harvest goal is met during the first trapping season, then
the second season will be closed.

NEW JERSEY

Beaver trapping season is concurrent with otter season.

Open Trapping Season

February only - by lottery system
Very limited season; 60-70 permits available statewide (annual
limit 3 beaver, I otter).

1990 statewide harvest: 140 - 160 beaver

Research Unit - sets up season and bag limit

Wildlife Control Unit responds to complaints
(1990 = 160 complaints)

1. Gives advice (e.g. fencing around trees; beaver pipes)
2. May install structural control devices
3. Live-traps and relocates about 10 to 20 beavers per year

Site-specific permits are issued to landowners who have problem-
beavers on their land and who did not get a statewide
permit. These special permits are only issued for February.

In times past, area managers would survey their areas for any
beaver sites, done once per year for three days.

NEW YORK

Numerous man-hours by state personnel are spent responding to
complaint calls.

1. Technical advice
2. If landowners are willing to install beaver pipes, the staff
will show the landowner how to do it.
3. A permit will be issued to the landowner if he wants to remove
the beaver.

Open Trapping Season - Split Season
(Example from Region 9)

December 14 - January 26 - No limit
March 7 - March 22 - No limit

*Season lengths and baglimits can vary by region.

MASSACHUSETTS

The Wildlife Section will respond to a beaver complaint call.
They have a four-step process when responding to a call.

1. Site visit
Nature of complaint
Public health
Public safety
2. May install beaver pipes.
A site-by-site evaluation will be done before installing a pipe;
history of complaint, food source, size of wetland that will be
created, etc. Pipes will be utilized for wetland enhancement
purposes.
3. If a landowner does not want to personally take care of a
problem, the Division has a list of trappers to which they may
refer.
4. Any-landowner who has damage to his property caused by wildlife
(e.g. deer, beaver, etc., except for non-game species) can kill
the animal under permit issued by the Division. Problem animals
so killed must be buried or turned into the state.

A data card is also issued with landowner permits or trapper
licenses. The card is used to collect information on how many
beaver were taken and the type of damage prompting their removal.

Facts:
Nuisance complaints - approximately 180 per year.
There are 351 towns in the state, and one-third of the
towns have had beaver complaints concerning road inundation,
blockage of road culverts causing flooding, etc. Between
$200,000 and $300,000 has been spent on actions taken to
correct these problems.
In the 1950's and again in the late 1980's, beaver were
relocated throughout the state; it was a "quick fix" but
the solution may have long-term negative results. The
relocation of beaver was done to reestablish the statewide
beaver population.

Open Trapping Season - (Best Management Practice)

November 15 to last day in February

After January 15, the conibear #220 and #330 traps are prohibited,
and leg-hold traps only can be used.

75% of the trappers use conibear #220 or #330 traps, and they
must be used as underwater sets. Leg-hold traps may also be used
with a drowning set.

Value of beaver - Pelt value currently low at $16

Castor glands: $90-100 per pound in Canadian auction
$45- 50 per pound at local auction

VIRGINIA

1990 - 593 killed statewide (beaver complaints)

If a landowner has a beaver problem, a control permit can be
issued out-of-season.

A game warden will review the complaint; if he feels there is
a problem, he will issue the landowner a permit. Depending on
the problem, the warden will set the number of beavers to be
taken.
Open Trapping Season

December 1 - February 29 - No bag limit

When fur prices are up, the beaver population goes down; when the
fur prices are down, the population goes up.

WEST VIRGINIA

County Conservation Officer will respond to beaver complaint
calls.

1. He will give technical advice to the landowner.

2. If the landowner still wants the beaver to be removed, the
officer will issue a special trapping permit.

Open Trapping Season

November 2 - February 29 Bag limit = 25 daily or 25 per season

1984-85 : 523 harvested statewide
1987-88 : 1064 harvested statewide
1989-90 : 962 harvested statewide

NORTH CAROLINA

Any landowner who has damage to his property caused by wildlife
(e.g. deer, beaver), except for non-game species, can shoot the
nuisance animal without permit. Problem animals so killed must
be buried or turned into the state.

If a nuisance animal is to be trapped from an area, a permit has
to be issued by a wildlife officer or biologist.

Open Trapping Seasons
Three Regions

Western: November 7 - February 12 (no limit)
Coastal: December 15 - February 28
Piedmont: December I - February 20

Appendix 9

Written Comments About the Plan Received from Other State
Agencies, Federal Agencies, Private Environmental Groups, or the
Public; Public Meeting and meetings with the Advisory Council on
Fish and Game. All entires in Appendix 9 are in chronological
order, based upon sequential dates of distribution, receipt, or
occurrence.

DEPARTMENT OF NATURAL RESOURCES AND ENVIRONMENTAL CONTROL

DIVISION OF FISH AND WILDLIFE

MEMORJAMDUM

TO Dave Small

FROM Bill Meredith

SUBJECT: Announcement for upcoming editions of the DNREC
Register

DATE May 23, 1991

Please include the following information in the upcoming editions
of the DNREC Register:

PUBLIC MEETING - BEAVER MANAGEMENT PLAN

AUGUST 15, 1991 - 7:30 P.M. - DNREC AUDITORIUM

To receive and review public comments about the proposed
statewide Beaver Management Plan, designed to promote
environmental benefits associated with beaver activities and to
contend with socioeconomic problems that beavers may cause.

Further information:
Contact Division of Fish and Wildlife, 739-4782.

DEPARTMENT OF NATURAL RESOURCES AND ENVIRONK ENTAL CONTROL

DIVISION OF FISH AND WILDLIFE

M E M 0 R A N D U M

TO Distribution List (DFW Personnel Only - See Below)

FROM Bill Meredith

SUBJECT: Review of draft Beaver Management Plan

DATE May 31, 1991

Enclosed is a draft copy of the Beaver Management Plan for your
review and any written comments that you'd like to provide. You
can write your comments either directly on the draft text or on
separate paper. We need to have any written comments given to
either Terri Fabean or me @y no later than June 14, 1991. If we
don't hear from you by the end of this two-week piriod, we must
assume that you'll be offering no suggestions or recommendations,
and that the draft plan is satisfactory to you.

An external agency review of the plan will be done from late June
through mid-July (see list on next page for preliminary
indication of external agencies who'll be asked to review the
plan.) We will hold a public meeting in mid-August for citizen
x-ev�ew and to rece�ve publ�c comments. AccordIng to our DCM?
grant, the plan must be "finalized" by the and of September.
Thank you for your cooperation and assistance.

DFW Distribution List

Bill Wagner Rod Harmic
Lloyd Alexander Rick Burritt
Bill Whitman Jim Reynolds
Greg Moore Chet Stachecki
Ken Reynolds Bill Meredith
Tom Whittendale Roger Wolfe
Randy Cole Terri Fabean
Charlie Lesser

Drainage Section, DSWC/DNREC
Conservation District Operations (E&S/NPS), DSWC/DNREC
Delaware Coastal Management Program, DSWC/DNREC
Wetlands and Aquatic Protection Branch, DWR/DNREC
Watershed Assessment Branch (includes Stormwater Management
Program), DWR/DNREC
Technical Services Section, DPR/DNREC
Delaware Natural Heritage Inventory, DPR/DNREC
Delaware Division of Highways, DOT
Delaware Forestry Section, DOA
Aglands Preservation Section, DOA
New Castle Conservation District
Rent Conservation District
Sussex Conservation District
U.S. Soil Conservation Service (Dover)
U.S. Agricultural Stabilization and Conservation Service (Dover)
Bombay Hook NWR (USFWS)
Prime Hook NWR (USFWS)

STATE OF DELAWARE
DEPARTMENT OF NATURAL RESOURCES
& ENVIRONMENTAL CONTROL
DIVISION OF FISH AND WILDLIFE
89 KINGS HIGHW Y
P.O. Box 1401
OFFICE OF THE DOVER. DELAWARE 19903
DIRECTOR June 21, 1991

Name

Address

Dear

Enclosed is a draft copy of a proposed statewide Beaver Management
Plan. The draft plan was prepared by the Delaware Division of Fish
and Wildlife. The plan's development is being supported by a one-year
grant from the Delaware Coastal Management Plan. The purpose of the
plan is to promote environmental benefits associated with beaver
activities, and to contend with socioeconomic problems that beavers
may cause.

We are soliciting your review and any written comments that you'd like
to provide. We need to receive any written comments from you @y no
later than July 15, 1991. If we don't hear from you by the end of
this three-week period, we must assume that you'll be offering no
suggestions or recommendations, and that the draft plan is
satisfactory to you. If you have any questions, please call either
Terri Fabean or me at 739-4782 (Little Creek Biological Field Office).

Further modification of the draft plan may come following further
internal review by the Division of Fish and Wildlife, from comments
provided by the Advisory Council on Fish and Game or from other state
and federal agencies (see distribution list below), or from the
general public following a public meeting planned for August 15.

Thank you for your cooperation and assistance.

Sincerely,

William H. Meredith
Fish and Wildlife Program Manager

WHM*jea

cc: William C. Wagner, II
H. Lloyd Alexander
Rodney L. Harmic
Chester J. Stachecki, Jr.
William R. Whitman
E. Greg Moore
Kenneth M. Reynolds

Distribution List:
Advisory Council on Fish and Game
Drainage Section, DSW/DNREC
Conservation District Operations, DSWC/DNREC
Delaware Coastal Management Program, DSWC/DNREC
Wetlands and Aquatic Protection Branch, DWR/DNREC
Watershed Assessment Branch, DWR/DNREC
Technical Services Section, DPR/DNREC
Delaware Natural Heritage inventory, DPR/DNREC
Delaware Division of Highways, DOT
Delaware Forestry Section, DOA
Agiands Preservation Section, DOA
New Castle Conservation District
Kent Conservation District
Sussex Conservation District
U.S. Soil Conservation District
U.S. Agricultural Stabilization Conservation Service (Dover)
Bombay Hook NWR (USFWS)
Prime Hook NWR (USFWS)

July 5, 1991

Mr. William H. Meredith
Div. of Fish & Wildlife Program Manager
DNREC
89 Kings Highway
P.O. Box 1401
Dover, DE 19903

Dear Bill:

I just finish reading the proposed statewide Beaver Management
Plan. I must admit that I have always felt sad that we americans
almost brought the beaver to extinction.

I have asked Lloyd Simmons, Manager at Redden State Forest and
Mike Brown, Manager at Blackbird State Forest to also review the
draft since they have dealt directly with beaver on the State
Forest.

In addition I cannot recall at any time when our foresters
working with the private forest landowner has ever reported a
detrimental beaver problem. So I can only conclude that if the
beaver has caused a timber management problem, the private
landowner has not made it one of his concerns.

I would like to present a couple of points for your consider-
ation. First, page 18: "Quite often timber of low commercial
value". Swamp white oak has a very high commercial value in
domestic veneers and cooperage. Also, it is sought out by
Europeans and Asians as a substitute to true white oak (Quercus
alba). Second, page 42: "We have identified 13. categories of
votential Plan participants:11 I do not see forestry as a partici-
pant in your listing or matrix. I think you need someone to speak
for the trees that the beaver are eating and using for housing.
Third, page 52: "Planning lorocesses and oppose competitive uses" ...

William Meredith
July 5, 1991
Page 2

ITCompetitive land uses.. (e.q. timber harvestincr, etc," The
statement, "no conscious intent", I assume includes man and beaver.
Oppose competitive uses (e.g. timber harvesting) . I suggest oppose
harvesting that is detrimental to the residual forest stand and
beaver habitat, but support harvesting that incorporate Forestry
Best Management Practices for to co-benefits of timber and beaver.

One additional note, the Forestry Section has a federally
funded program titled "Stewardship Incentive Program". This is a
cost-share for forest landowners to perform a conservation
activities, the development of wildlife habitat is one of those
programs. Jim Wilber form you wildlife staff is a member of the
stewardship committee. I would contact him for what he is doing
and how you could use these funds to help landowners in there
timber/wildlife practices.

Thanks for the opportunity.

Sincerely,

Timothy A. Kaden
Forester Supervisor

TAK/d

cc: Roland Derrickson, Acting Forestry Administrator

United States Department of the interior
FISH AND WILDLIFE SERVICE

41 BOMBAY HOOK NATIONAL WILDLIFE REFUGE
R.D. #1, BOX 147
SMYRNA, DELAWARE 19977

July 8, 1991

Dr. William H. Meredith
Fish & Wildlife Program Manager
Delaware Division of Fish & Wildlife
P.O. Box 1401
Dover, Delaware 19903

Dear Bill:

Thank you for the opportunity to review the draft copy of the Beaver Management
Plan. It was very comprehensive and well done. I only have two minor comments:

1. Page 24: Our greatest problem (Public Lands - Conservation/Recreation
Area) with beavers is their habit of plugging water control structures
when we are actively trying to manage habitat for waterfowl, usually in
the "drawdown" phase of impoundment management. You may wish to address
this.

2. Page 2 : Even though national wildlife refuges could be potential release
sites in certain instances; the policy is not to introduce animals of any
kind on a refuge without extensive tests to rule out transmission of disease
to extant wildlife populations. There would be more paperwork "hoops" to
jump through than release sites on other public or private lands.

Again, I appreciate the opportunity to review the plan. Biologist Frank Smith
of my staff also reviewed the document.

Sincerely,
,:::Paul D. D 'ly
Refuge Manago'r
Bombay Hook/Prime Hook Refuges

PDD/sms

STATE oFj DELAWARE
DEPARTMENT OF NATURAL RESOURCES AND ENVIRONMENTAL CONTROL
DIVISION OF SOIL AND WATER CONSERVATION
89 KINGS HIGHWAY
P.O. Box 1401
OFFICE OF THE DOVER. DILAWARE 19903 TZLIEPHOHL (302) 739 - 4A I I
DIRECTOR

July 15, 1991

TO: Bill Meredith, Fish and wildlife
Fr: Kevin Donnelly, District Operations..
Re: Beaver Management Plan
overall, I am impressed with the breadth and depth of the plan.
It is well organized and well written. My comments should be
considered to reflect the views of the New Castle and Kent
districts. Sussex district indicated that they were working with
Dick Smith to ensure coordination with a key component of their
operation.
One of the first questions that comes to my mind when reading this
report is "Who is our audience?". Was this written f or the
scientific community, key decision makers or the general public?
Will it be used as the technical reference for future policies or
is it part of the department's initial policy for beaver
management? The answers to these questions will determine the
final content and format of this plan.
If it is written for decision makers or general consumption then
we need to simplify the language, shorten the paragraphs and
sentences and make it more visual. I would hope the I&E section
has software such as Right Writer that can analyze a document and
offer suggestions for improving readability.
In terms of format, perhaps it should be reorganized to clarify
what issues need decisions, where more study is needed and where
we are relatively certain of our position?. I would suggest that
our target audience dictates whether or not the first section of
the report addresses biology or the roles and responsibilities of
the agencies charged with implementing such a plan.
To make the document more user friendly I would like to see an
Executive Summary, approximately 1-1.5 pages long, that succinctly
spells out the who# what, why, where and how much of the draft
plan. This summary should be included as part of the plan and be
able to stand alone if necessary. The section entitled General
Policy and Plan Purpose is a good start. We khow from past

experiences that our elected decision makers are not likely to read
this entire document. The summary should provide them with the
most important information within your plan.
I hope that we can improve the graphics, especially Figures 1-4-
Our GIS section and their computers should be able to assist in
this effort even with the limitations of budget and copier
technology. our society thrives on the visual display of
information; we need to capitalize on this fact if we can.
I like to now concentrate on some specific concerns. The first
one centers around Table 1. The last sentence in paragraph 1 on
page 43 reads 11... the advisory input of all interested parties
must be seriously considered-" The matrix on page 44 fails to
communicate this commitment to coordination. A matrix, by design,
displays discrete boundaries of responsibility. This is not the
message that you want to convey.
Specifically, I am concerned that the districts, who are identified
as the primary implementers of structural activities, along with
the primary or partial responsibility for the long term maintenance
and repair of many structures possibly effected by beaver, are not,
at least at this point, displayed as part of the team responsible
for determining either the problem or the corrective action. In
most cases the authority to determine the problem and the action
@ever includes a representative from the group charged with the
implementation of the action.
We need to go beyond the matrix and develop a table or figure that
illustrates the level of coordination the authors of the plan
describe on page 43. Without this extra step, it may be perceived
that the plan contains a flaw in it's approach for assessing a
problem and devising a mutually agreeable solution.
The districts can provide help in implementing the recommendation
of developing a cost-share program(s) to assist in managing the
states beaver population. All three districts have many years
experience in cost-share programs and their experience will prove
very valuable no matter what form this cost-share program takes.
You must understand that such a program, under our current
allocation, must compete for funds targeted towards our current
water quality priorities.
other changes that you may wish to consider include:
pg 21 - Change Delaware Forestry Section to 11DOA - Forestry
Section"

pg 26 Should the tax ditch category be expanded to include the
lands drained by them?. 'I am concerned with not
specifically mentioning ag land in this prioritization.
Farmers are going to want to know where they place on
this list.

pg 26 For consistency sake this list and the one describing
beaver problems on page 42 should be the same. I mention
it because rural private land is listed last on page 42
and this may raise a flag in the agricultural community.

pg 29 Criteria #3 - Where did the 20 yards and 5 feet come
from? I'm sure the ag community will want to know.
Perhaps it should be stated in a less definitive manner
until the plan has undergone public review. (Bill, I'll
work on this.)

pg 33 Websters' not withstanding, "dispatch", in my opinion
is a weasel word that government uses too often. Let's
say what we mean and use words that people understand.
How about changing the word "dispatch" to "annihilate" or
"exterminate"?

Finally, shouldn't the table of contents contain a separate list
of figures and tables?

Bill, this is a real strong effort for,first review draft. Let me
know where and how I can help this effort and I'll do all I can.
I'm sure the districts feel the same way.

cc: John Hughes
Andy Manus
Dick Smith
Larry Irelan/Andy Burger
Art Malinowski/Ernie Zimmerman
Beth Horsey/Cashar Evans
Fred Mott

STATE OF DELAWARE
DEPARTMENT OF N ATURAL RESOURCES
& ENVIRONMENTAL CONTROL
DivisION OF WATER RESOURCES
89 KINGS HIGHWAY. P.O. BOX 14901
SU:FACEWATER MANAGEMENT SECTION DOVER. DELAWARE 19903 (302) 739 - 5726
IN TERSHEO ASSESSMENT BRANCH (302) 739 - A590
POLLUTION CONTROL 014ANCH 1302) 739 - 5731
FACILITY SUPPORT BRANCH (302) 739 - 5081
WrTL^NOS & AOUATIC p*arECTION BRANCH MEMOR)MUM (302) 739- 4691

TO: Bill Meredith

THRU: Bill Moyer
_ I., I r4@,
FROM: Dave Saveiki-
B -\--)

SUBJECT: Draft Beaver Management Plan

DATE: July 15, 1991

The wetlands and Aquatic Protection Branch (WAPB) has completed
review of the Division of Fish and Wildlife's draft Beaver Management Plan.
We welcome the opportunity to provide our input on draft plans such as
these which affect wetland and subaqueous land resources and would like to
continue to be involved in providing input in your Division's wetland and
aquatic management policies and programs, preferably as early an possible
in the process involving such efforts. Early collaboration in such efforts
can only lead to better, more implementable programs.

Regarding the draft Beaver Management Plan, the WAPB supports the
objectives of the plan and recognizes the benefits and challenges of
management of beaver compatible with other ecological and social
considerations.

we have several substantive comments regarding the draft plan to
include:

1) Include in Section VIII l.A. under potential beaver release site
criteria to be considered, language addressing extant site characteristics
relative to rare or endangered plant or animal species and unique aquatic
and wetland community types. This would insure that otherwise beneficial
beaver induced hydrological and ecological alterations do not conflict with
other sensitive resources (e.g. extended hydroperiod causing unacceptable
damage to Atlantic white cedar communities). Addition of such language
would be consistent with other textual sections addressing this issue found
on pages 22 and 24 of the plan.

MEMORANDUM
Page Two
7/15/91

2) Criteria considering potential agriculture conflicts at potential
beaver release sites (Section VIII l.A.3.) may not adequately address,
through the proposed 20 yard isolation between potential wetland edge and
cropland, agriculture conflicts since the "potential wetlands edge" may be
difficult to predict due to the uncertainty of the ultimate elevation of
any beaver damns, the variable success of beaver flow-through pipes at
managing water levels, and the relatively flat topography of many sites.

3) We request that the Wetlands and Aquatic Protection Branch play an
active advisory role for those situations affecting wetlands or subaqueous
lands in assisting in management decisions as outlined in Section X numbers
1 (determination of a problem) and 2 (determination of desirable action)
for all five listed types of beaver-caused problems.

Management of beaver impacts on wetlands and subaqueous lands is but
one opportunity available enabling our two agencies to work proactively
toward achievement of wise management of our aquatic habitat resources. We
anticipate this potential and look forward to you response. Please feel
free to call us if you should have any questions regarding our comments.

DES/ca

cc: Jerry Esposito
Bob Zimmerman
Tony Pratt

DES9159

STATE OF DELAWARE
DEPARTMENT OF NATURAL RESOURCES
& ENVIRONMENTAL CONTROL
1_-)fV1SION OF PARKS & RECREATION
89 KIr4GS HIGHWAY
P.O. Sox 1401
DovER. DELAWARE 19903

7 August 1991

X E M 0 R A N D U X

TO: William Meredith, Terri Fabean

FROM: Leslie D. Trew, Keith Clancy, David Rothstein, Delaware
Natural Heritage Inventory

SUBJECT: Comments on the Draft Beaver Management Plan by the
Division of Fish and Wildlife

cc: William Wagner, Chazz Salkin, Susan Laporte

We have reviewed the Delaware Beaver Management Plan drafted by
the Division of Fish and Wildlife and would like to provide our
comments on this plan.

The staff of the Delaware Natural Heritage Inventory would prefer
that no extrinsic manipulative techniques be employed to manage
the beaver. A hands-off policy would be the ideal situation.
However, we are aware that there have been numerous complaints
recently regarding the beaver and its activities and that in
certain instances an active role of management is warranted in
order to alleviate hardships created by beaver activities. In an
ideal world the beaver and humans could live together
harmoniously.

It was mentioned, although briefly, in the management plan of
instituting an educational program to emphasize the environmental
importance of beavers and their activities. we strongly believe
that education can be an important tool in alleviating some
problems associated with beavers by making the public more aware
of the value of the beaver and more tolerant of its activities.
The recent boom in housing developments throughout much of
Delaware adjacent to, and in some cases in, wetlands has
undoutedly resulted in many recent beaver complaints from the
public. We encourage the Division of Fish and wildlife to pursue
a beaver education program vigorously as part of their overall
beaver management strategy.

Ve&&-aw"a qAAW 0C4X2 4ee#e,0e1&
7-

Specific Heritage concerns abou t the beaver plan:
Potential Relocation Sites/Transplanting Beavers
Relocation sites must be chosen with extreme care and long-term
monitoring of these sites should be enacted to ensure that
transplanted beavers remain on site. Translocation of nuisance
beavers is recommended only in situations where suitable habitat
is available. Proposed sites should be thoroughly surveyed for
rare species as well as unique natural communities. While the
influence of a beaver population in a habitat may be beneficial
to some species (e.g. waterfowl, herons and allies), it may not
be for others. Translocation of beavers will certainly alter the
habitat (assuming they remain in their new home) and could
adversely affect insect, herpetile, and bird populations. Plant
species are most vulnerable to these changes. we would like to
have the opportunity to review potential release sites for
presence/absence of rare species. Flooding of a site by beaver
damning could destroy populations of rare plants or similarly
have negative impacts on a unique or otherwise pristine (i.e. in
a relative sense) natural community. For example, a site in
Connecticut containing 15 rare plant species was severely
impacted by beaver activities (Connecticut Natural Heritage
@rogram). Likewise, a lake in New York which was dammed resulted
in the. loss of the federally endangered orchid, Isotria
medeoloides, in the wooded areas surrounding the lake (The Nature
Conservancy, New York Chapter). We would like to avoid the need
to relocate beavers a second time in the event that the beaver's
new home contained rare species or unique natural communities
that would be impacted by the animal's activities.
The problem of habitat alteration also exists in extant beaver
ponds. Removal of a population would result in water flow
augmentation, a change in water quality, and the alteration of
the habitat. Before a beaver is relocated, it must be known
which other species and natural communities will be affected, and
how will they be affected.

Translocation is a popular method in beaver management, but one
which often results in unforeseen consequences. Transplanted
beaver have been known to range widely from their new dwellings.
Research has documented movements from 5-200 miles from the
release site (see Hibbard, E.A. 1958. Movement of beavers
transplanted in North Dakota. J. Wildlife Managem. 22:209-211).
will frequent monitoring occur in order to determine if the
transplanted beaver are remaining in their new homes.
How will relocation sites be chosen, particularly those potential
sites that are on private land, to ensure that the beavers will
not be causing problems to the public in the future? Long-term
monitoring should be implemented to track breeding success and
any dispersal events from the site.
A beaver colony is more appropriately described as a "family unit"
since beavers exhibit a high degree of fidelity. Beavers often
mate for life and the family frequently consists of from 4-6

individuals that may represent several generations. Site
fidelity is a factor in familial interrelations. A good
understanding of the sub-population at the site is necessary.
The potential for disruption of the breeding cycle as well as the
family unit is apparent. Another important consideration in
translocating beavers is the fact that the process Is labor-
intensive and frequently the adults need to be anesthetized prior
to relocation (.Seal, U.S. and T.J. Kreeger. 1987. Chemical
immobilization of furbearers. Pages 191-215, in M. Novak, ed.
Wild furbeArer management and conservation in North America.
Ontario Ministry of Natural Resources).
As you are aware much of the beaver's habitat has been destroyed
by human activities. Each year more of this habitat is being
encroached upon. It is difficult for the beaver to go about the
job of being a beaver. Perhaps the Division of Fish and Wildlife
or DNREC could become actively involved in the review process for
development projects to help these projects avoid impacting
beaver habitats (such as building far enough away from wetland
habitats to avoid any flooding problems caused by beaver dams).

structural Alteration of Lodges

Structural alteration of the lodge is a good alternative that
should be pursued; although it may require funds above those
needed for relocation dependant on the method employed.
Monitoring will be necessary. Another consideration is that
methods utilized will be experimental and will need to be fine-
tuned from site-to-site. Readjustment of the water levels will
allow the beavers to remain in the area, as well as placate the
complainant. If possible methods to alter water levels should be
attempted before beaver relocation. As the beaver plays an
integral role in the ecosystem, water flow alteration should be
conducted with the habitat in mind.

Remedial Response Optio ns if a Substantive Beaver-related
socioeconomic Problem is occurring
@hile a study of beaver lodge locations has been conducted, there
is little information available regarding site/statewide
populations. An extensive population/breeding ecology survey
should be undertaken prior to the implementation of the proposed
management practices - Estimation of numbers of individuals in
each family is time consuming and probably impractical. A
knowledge of breeding success, dispersal rates and distances and
sex ratio for Delaware's beavers is important if a population is
to be minimally disrupted.

Translocation of individuals and structural alteration of dams
are the most viable options presented in the plan. While
acceptable, these measures should only be used as a last resort.
There are a variety of control methods which were not discussed
in the plan, which should be initially explored at each site
which are outlined below. Any alternative selected should be
implemented on a site-by-site basis, following thorough

examination of the beaver population, including a comprehensive
biological inventory of proposed release and existing sites* The
sterilization, dispatching and public trapping of beavers are
extreme management measures, and for reasons to be discussed, are
not recommended.

Alternative Control Measures

Individual trees may be protected by enclosing the bottom 1 m
with heavy wire mesh, hardware cloth, or galvanized metal.
Volunteers from the Nevada Humane Society wrapped 1200 cottonwood
trees to prevent beaver-related damage.

Commercial deer repellents may deter beavers, but may have an
unpleasant odor (de Almedia, M.H. et al. 1979. Nuisance furbearer
damage control in urban and suburban areas. Wild furbearer
management and conservation in North America. Ontario Ministry of
Natural Resources). Beavers may avoid trees painted with diluted
repellent (1:50) for three years or more. Experiments regarding
the effectiveness of this method show a learned intolerance of an
area to which repellent has been applied.

A short-term solution may include artificial feeding. Placing
food in an acceptable den area has proven to be a successful
alternative, allowing one dam to be dismantled, while another one
is created in an appropriate area. The reliability of this
method is unknown.

Artificial scent mounds are effective in deterring transient
beaver from using existing but uninhabited lodges (Muller-
Schwarze, D. n.d. Canadian Beaver at Acadia National Park.
National Park Service Cooperative Research Unit) - Castor
secretion is natural and is released as a territorial marking.
So effective is this method, that sometimes even resident beaver
are affected (Svendson, G.E. and W.D. Huntsman. 1988. A f ield
bioassay of beaver castoreum and some of its components. Am.
Midl. Nat. 120:144-9.)

Exclusion fencing of small critical areas such as culverts,
drains, and small ponds or lakes may prevent damage (Miller, J.E.
1983. Beavers. Prevention and control of wildlife damage.
University of Nebraska).

Electrified barriers can be highly successful in controlling
beaver flooding at sites where the activity of beavers is
otherwise acceptable. These systems work best in areas with
little public exposure as vandalism may be a problem (Muller and
Schwarze, n.d. On a study of the behavioral and population
ecology of the Canadian beaver at Acadia National Park. National
Park Service Cooperative Research Unit, SUNY, Syracuse, NY. 86
pp)-

Availability of winter food supply is the most important factor
affecting beaver distribution and abundance. Hence, it is
theoretically possible to affect beaver population through

manipulations of the vegetation (Hill, E.P. 1982; slough and
Sadleir, 1977). In general, activities which favor young woody
deciduous growth will favor the beaver. other management
practices may hinder the success of beaver at a site. This
option may not be advantageous in Delaware due to the beavers'
opportunistic feeding habits.

Beaver damage to roads and culverts may be prevented by
anticipating the likelihood of beaver activity and properly
designing the road or stream crossing. Relocating roads or
edifices may be more complicated, and would have to be
coordinated with DELDOT. The study of beaver distribution should
be substantive enough to make recommendations to city, county and
state planners. People actively involved with beaver management
should regularly attend planning and development meetings.
Sterilization, Dispatching and Public Trapping Season

These methods should be avoided if possible. As mentioned,
sterilization is costly, and also requires the resources for live
trapping. Pre- and post-operative care are required as well.
This method is not suggested as its effects on the population are
irreversible and its effectiveness in population control is
questioned.

Dispatching of problem beavers is not recommended for a variety
of reasons. As discussed earlier, the stability of the
population is dependent upon monogamy, a 3-year maturity cycle
and familial relations. The dispatching of one or more
individuals may have unanticipated affects on a "family".
Likewise, the beaver is an integral facet of its environment.
The elimination of the beaver from its habitat may have a
resounding impact on numerous species.

At this point in time, a public trapping season is premature.
Without a firm knowledge of statewide abundance, one cannot
effectively regulate trapping. Determining the appropriate
number of beavers for a particular area or management unit can be
a difficult and often subjective decision. Your example of
having a statewide harvest of 300 beavers per year would deplete
the current state population by 40%, assuming a total of 750
beavers. A harvest of one-third of the population has been
suggested by researchers, with the stipulation that season length
and localities be varied (Hill, 1982; Novak, 1987b; Ermer, E.M.
1988. Manageing beaver in New York. The conservationist. State of
New York.)

Despite the difficulty that is sometimes encountered in totally
removing beavers from an area, their confined ecological limits
and low reproductive rate, together with the ease with which they
may be trapped, make beaver vulnerable to overharvest. Avoiding
beaver problems through regulated harvest recently has become
more difficult because low pelt prices in some areas discourage
many trappers.

The possibility of capturing non-target species is high. Raptors
and herons are most susceptible, but many other species have been
caught in leghold traps.

The estimate of 750-1500 individuals is wide-ranging. It may not
represent a stable population. A regulated season would have
dramatic impacts on habitat, and non-target species. As
mentioned in your plan, this method is imprecise. A skewed sex
ratio may result from large-scale trapping and unpredictable
population fluctuations should be anticipated. Likewise, a
regulated season may not effectively put an end to the problem
beaver(s). Alternative means which operate on a site-by-site
basis are preferred.
p
All management techniques should be geared to nuisance beavers;
those which occur in already developed areas. Anticipation and
proper planning for new developments should eliminate much of the
problems associated with beavers. They do not become pests until
humans encroach on their breeding grounds.

We appreciate the opportunity to comment on the Beaver Management
Plan and we hope that you will give serious consideration to the
concerns addressed above by the Delaware Natural Heritage
Inventory.

DEPARTME11T OF NATURAL RESOURCES a ENVIRONMOnAL CONTROL

DIVISION OF FISH & WILDLIFE

MEMOR,ANDUM

TO: Bill Wagner, Lloyd Alexander, Bill Whitman, Greg Moore,
Ken Reynolds, Rod Harmic, Rick Burritt, Chet Stachecki

FROM: Bill_t4eredith, Terri Fabean
1::@@ 7A_ YA Z
SUBJECT: Propoge-dImmediate Action-Steps to Implement the Beaver
Management Plan

DATE: August 14, 1991

The latest draft of the Beavdr Management Plan distributed to you
(August, 1991) had a blank Section X111: "Proposed Immediate
Action-Steps to Implement the Plan". Based upon written comments
received to date about the Plan, and on three recent meetings in
which we received Division and Department input, we've prepared
the draft text for Section XIII (see enclosed). The recently
received input was primarily informed opinions about varied
topics, and sometimes revealed differences of opinion amongst the
contributors, or sometimes did not mash with technical facts in
the Plan; however, most input offered was decipherable and will
strengthen the Plan. We've done the best that we could in
devising 8 proposed action steps, and believe that all of these
recommendations are consistent with the Plan's content and with
what we've heard from you. However, since we also know that
suggesting anything to do about beavers always seems to elicit
counterpoints, we won't be too surprised if you'll differ with
some of the proposed actions.

What we now need is for you to edit the attached, both
conceptually and for "wordsmithing." We need to have this
Section finalized, along with any policy or organizational
decisions that may have to be made, by no later than August 30th.
The Plan's final version must be completed and printed by late
September. If we don't hear from you by August 30th, we must
assume that the 8 proposed action steps are satisfactory to you
and, as such, they'll appear in the final plan. Where policy or
organizational decisions have to be made, we request that such be
made by the appropriate authorities and be conveyed to us in a
clear, timely manner. If you can take the time, you may want to
give us some verbal feedback (for matters over which you have
pressing concerns) before tomorrow night's public meeting, which
would help us to give a stronger presentation and avoid making
mistakes.

Thanks for your cooperation and assistance.

WHM:Jea

PUBLIC MEETINGS

I. Attendance at Public Meeting on August 15, 1991 (DNREC
Building, Dover, DE) for plan presentation and question-and-
answer period; public was given until September 6, 1991 to
provide any written comments which individuals or organizations
wished to submit.

Carl Hughes, Delaware City, DE
Fred M. Goldsborough, Smyrna, DE
Mary J. Stachecki, Harrington, DE
John Stevenson, Townsend, DE
J. D. Metzger, Wilmington, DE
D. Scherger, Dover, DE
Robert Piacinski, Dover, DE
Mr. R. A. Raley, Lewes, DE
Mrs. R. A. Raley, Lewes, DE
Bud Holland, Townsend, DE (New Castle Trappers Assoc.)
E. D. Buper, Dover, DE
Leslie G. Porter, Wilmington, DE (Delaware Action for Animals)

William C. Wagner II, DFW/DNREC
H. Lloyd Alexander, DFW/DNREC
Chester J. Stachecki, Jr., DFW/DNREC
Jim Reynolds, DFW/DNREC
Paynter Lynch, DFW/DNREC
Dick Nutter, DFW/DNREC
Randall V. Cole, DFW/DNREC
Roger J. Wolfe, DFW/DNREC

Terri Fabean, DFW/DNREC
William H. Meredith, DFW/DNREC

II. Meetings with the Advisory Council on Fish and Game; short
presentations and question-and-answer peTiloaiT.-'

1) June 4, 1991 - Short overview and distribution of draft
plan.

2) August 27, 1991 - Plan overview and slide presentation
on beaver biology/ecology.

FOR NEW ENGLAND FAX 4018464qMO PAGE 01

2qRends
of
Animals

August q1q5, q199q1

Dept. of Natural Resources
and Environmental Control

Att.: Terri Fabean, Div. of
Fish and Wildlife.

Dear Me. Fabean:

As I indicated in our telephone conversation
this morning, Friends of Animals, Inc. is anxious
to assist any individual, organization, governmen-
tal body or agency in their effort to eliminate or
mitigate the problems associated with the expanding
beaver population in your state. Obviously, we are
committed to the exclusive implementation of non-
lethal measures.

Please consider us to a resource at your dis-
posal in regard to the above matter.

Prbwun rend, PqMMd9qM sincerely,

a NNIONAL MqMDOUqMM&
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270 Houle 20q6
Flindcrs. New Jersey 0783qg;
q(201q) 027-SGqIqI
4q&8qN FAX '8qU4qSqE8qR--(201) 927-5617

OIFFICERS
K. Will-am Wisarrkim
Chak-Man of Ift Board
Coloman sulica, Ezq.
charrmatt Emotilus OUTGOING - - - - - - - -
O.J. Ramsey, ESQ.
V40 Cqurmorl
Or. Amy Freeman Loa F A C S I M I L qE TRANSMISSION
Secretary
John A. Hoyt
Aresidant

Paul 0. Irwin
qb0curfive Vko qfqtsidanY BILL q1q1qBRIDqETH 2qM8qM: AUGUST 15, 1991
Treasurer
Patricia FoqfqtA
Soniw Vice qfqtside"(
Mufdaugh Stuart MAddem. Esq. qF2qM4: BOB 4qREDER RE: BEAVER DAMAGE & CONTROL
Vo Podo"ISofea Counsol

Patrick S. Parties
vxs Prasidenq Services
Of. John W. Grandy
Vke pfestdonrlwaalife 4
EAV00111neftf 4qZqiIS qI4qESqSAqGqE CCqNSqL2qM OF q7HqIS PAGE PLUS 9 PAGES qFqO2qLqt2qZ%2qM2qZ.
Phyllis Wright
Vice Anl-&Is SPECIAL q1q1q4SqI4qMC8qTIMqIS OR CC8q*8qM8qM
Dr. M1q0301 W. Fox
Woo qfqtsidont1form Animals &
fil;oornscs

Dr. Carat 9r*wrwmg
Calff"Arl GUM@. Esq.
Irene Evans
111togina, Gsuar l1rarikomborg
Harold 1q. Gardiner
Allce A. Gray
Or. Jano Goodall
Paul Rencks
GI I
livia Humnicl,to
Los io FR. Inglis
01 'Amy Froeman Lit
Jack W. Lydman
Virgin 14 Lynch
Mani pripperons
O.J. ptamsey. qUq,
Marilyn 0. Saylor
Robot Sorock
Srcrokl4q4owal
John E. Tah
Cairroll ThOtt
Vlqofqs Wqobqaqr
Mqoqbqeqrqt qFq. Walborn. Esq.
Marilyn qWqilqhqcqlqrqn
qXq. qWqiqtqlqiqaqrqn Wiseman

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Aids, Flemming
Virginia Mqilqlqikqoqn q'qNqaql8qlqonq.q18q1 4q10q1qcqad4qqquqaqrqlqeqrqsq;
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2100 tq. Street. qN%qv
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The IUMOne SocqictY of the United States
bild-Atlantqic Regional Office
Bartley Square
270 Route 206
Fqlanqdcrs, NJ 07S36
(201q) 927-5611

August 15, 1991
2100 L SIM,-% NqW
Washingqwri. VC 20037

qQN-FICERS Hr. William qMerideth
K William Wiseman
Chairman of qW OqW4 Delaware Fish and Wildlife
Coltinan Burks. Fqw, Dover, Delaware
Chd&Mq" qfqtontus -------
04 Almsery, EqM FAX Transmitted 8/15/q91
Yke Chairman
Or. Amy Frqmmain Let
saciotery
John A. Hoyt
pqmVem Re: Proposed Beaver Management Controls
Pow 0. IMVIA HqSUS-MARqD Case q0 91-271
qbqwud" Vk# Maidenly
possurer -
Roger, A. Kqfqtlat E-q%
VICS AV511011knaGollq" CALIA111 Dear Mr. qMrqideth,

5q0410st STAFF
vics: rRvstoqmIll It is our understanding that your agency in
Patricla litorkan considering methods to control damage caused by
sefda? V/ce Assla"t
Owe A. oldIgn wild beavera, and that a discussion oqf that
Gowammom A018qMAR issue will be hold this evening in Dover.
Patty A. Ancth
qfqto Edocaroon
Ix Michael W. 19ox If it were not for the late notice# The Humane
Aerm Animals 6 946mics Society of the United States (HSUS) would have
or. jonn W. Grendy had a representative qin'attandenceo We regret
wpoilto 6 tfablist Proqfqtqwir
Jan A. Hrliks. Esq. that we can not physically be there but do hope
criviromqmmf that the view points and suggestions contained
I?Iomas J. Huritt within this letter may be shared by your Agency
conimuor as
DL Ramon Lqwkw well as all those in attendance.
Field Sonricos
0& MAMIA L $160hons We also understand that there are three proposed
Lilibqmicry Animals
David X. WITIS methods on your agenda, which are;

phylliz "Iota
Companion Animists 1. By killing the animals
Murcaugo aluan Mo4den, Esq. 2. To trap and transfer
swqw C'xinsol 3. Compensation to the effected property owners

DqMF.CTIORS
H. 1. (Sonny) Bloch
Women Burka. EsQ.
Anita Schownskof Coups. q&Q.
Irono Event HSUS POSITION
Carroll illorgharn-rnrift
Regime Bauor FatikenqWig
Harold N. Garoinor 1. Killing the Animals
Alice A. Garay The Humane Society of the United States (HSqUSq)
Dr. Jana Oqooqoqlqill
LOS" A. Inglis representing almost 5,000 members and
John Kay constituents within the state qo8qf Delaware and
Ilk Amy Frqeqsmqaqn Lee
qJ8quk W. qLyqdqmqtqm most of all on behalf of the animals,
Vqiqrqgqirqlqiqs qJyqnqrm intensely opposes the killing qo4qf the beaver&.
qC8qU Ramsey. Esq.
Mqaqrqgyqn q0q. q5q6q,q0q0q1 Even where the killing o2qf beavers Is legal# it
Aqcqbqen Sqoqmqex will not prevent the problem from reoccurring.
John q4. Taft
q1qsqtqry qC, qTq. qhqomqaqsqoqm I6qf the habitat remains the same, new animals
qlqo0qwqsw6qoqoqr will move in acme time in the future.
2qf2qtqbqeqn F. Wallow, Esq,
or. qDqaqvqv q0q. qWq$qoqDqerqs
Marilyn 6qWhqeqirn continued
K. q@ qWqiq;qvqrqn qWqiqsqorqrq(qM

1 -rHU 1 4 416 IISUS-M A RO F21 0 S

page 2

2. Trap and Transfer
Live trapping would seem an acceptable
alternative to killing, however, splitting Of
the family groups usually ends in the death of
moat of the beaver faxilye Where legal,
beavers can be live trapped but because of
their strength and large teeth special,
expensive cages must be used and it requires a
knowledgeable person to set them. if the trap
is set incorrectly the animal could be drowned
or killed by the closing mechanisa. This
alternative, like killing will not provide
long term relief if the habitat remains the
same.

3. Compensation
This is not an animal protection issue,
however we realize that if damages are
compensated for by the State, the immediate
pressure to eliminate the animals will be
relieved, for now, and may alleviate the
need to destroy or transfer the animals.

Our recommended solution lies in removing from
the existing habitat those things that attract
and maintain the beavers in the concerned area.

We have attached to this letter a copy of XSUS
Shelter Sense, April 1987 article, entitled,
"Busy Beavers Can Be Persuaded to Leave Home".
Within this article are numerous suggested
solutions to alter the environment to cause the
beavers to move elsewhere, naturally.

The Humane Society of the United States would
strongly urge that your agency consider this
alternative to killing and we would be happy to
have you speak directly to our Wildlife Director
and expert, Dr. John Grandy, who can be reached
at our Washington DC Headquarters, 202w452-1100.
Of course this office which represents Delaware
will continue to offer any assistance possible to
reach an amiable solution.

continued

AUG-15-97: THU 14:46 HSUS-MARO

page

Thank you for the opportunity to share our views
and ideas with your Agency and on behalf of the
animals, I remain
Sincerly,
4qZc6q*q@Reder
Field Investigator

cc: Dr. John Grandy

Washington News Journal

Jill Church, Delaware Action qfor Animals

AOG-15-91 THU 14:47 HSUS-MARO q0!5

Volume q10
Number 3
"April/MayqI98q7

2qMINSIDE:
aRidding qOssivers Humanely For the people
0 qDog Attacks. Owner In
Prison who care about
0 Pot Food Discounts community
animal control

7,
2q3

AAA.-

DogBqiqt4qesq: our community may be the next to be involved qin & severe dog
6qYbitqe incident. In the past 12 months, 14 people have been
Ho16qv0qv64qProt52qWed killed nationwide an a result of dog attacks. Now is the time to
Is Your review your communityq's animal ordinance so that your organization;
Community? will be Prepared before facing such a tragedy.
by Dabble Reed Some co4q=unities have passed unenforceable vicious dog
ordinances. Many laws are not based on knowledge about animal
behavior, animal welfare, and animal bites. Since today's
citizens are move apprehensive about their safety and the security
of their belongings, it is common for a person to own a guard dog
in addition to or 8qin place of q& gun. But many laws place the
burden of Punishment on an offending animal, when# in fact, it is
an irresponsible owner who usually is the direct or indirect cause
of a dog's severe bite.
Continued on next pa0qVqe

AUG-IM-91 THU 1-4:47 H668-MARO

Busy Beavers rhe second article In a series about humane solutions to wildlife
Can Be problems that began with the march 1987 issue.
Persuaded To
Leave Homel eavers' legendary capacity for hard work has endeared them to
Bsomt people, but their industrious activity can cause bad will.
when they move into urban or suburban neighborhoods. Fortunately.
many people prefer to solve such conflicts without killing them.
It is possible to evict beavers or to find ways to live peacefull3i
with them without causing them harm. Further, the humane approact-
to beaver control is usually the most practical.

Beavers will live wherever there is sufficient food and water and
quickly will make themselves at home in ponds, lakes, and
streams. In streams# they busy themselves with building a dam to
create a more desirable environment, which results In trapped
vater that may flood crop lands, pastures# or lawns. Beavers cut
down ornamental trees for food or dam construction materials.
They also may eat twigs and bark, leaving the damaged trees to
die. Some landowners may.not enjoy watching their carefully
landscaped yards being redesigned by beavers.

No repellents# toxicants, or fumigants are registered for use in
controlling beavers. A landowner with a beaver problem may resort
to shooting or trapping the offending beave .rs because he or she
knows of no other practical solution. This simplistic approach
includes several drawbacks: The taking of beavers Is strictly
regulated in most statesi may only be done legally at certain
times,-using specified techniquesp and usually requires a
permit. Even where killing beavers is legal., it will not prevent
other beavers from moving in and restarting the problem. Such
drastic measures fail to acknowledge the aesthetic value of
beavers as fascinating and complex animals, nor do they recognize
beavers' important role in our cultural and natural heritage.
Continued on next page

UG-In-91 7HU 14:4@ HSU'S-MARO P.07
There ace effectivee nonlethal techniques ror controllina nuisanc4
beavers, and these can be best understood by first understanding
beaver biology.

The beaver (Castor canadensis) Is the largest North American
rodent. it is monogamous and remains faithful to its mate.
Females produce one litter per year, usually between March and
June. A typical litter contains three or four kits. Young
beavers art able to reproduce by the age of 18 months. A beaver
colony commonly contains eight to 13 animals, Including an adult
pairt kits from the previous spring, and yearlings. Two-yeac-old
beavers leave in search of unoccupied territories to colonize.
Dispersing beavers may travel many miles in search of now homes.
The two most important requirements for good beaver habitat are
plentiful food and deep water. The largest portion of their diet
includes tree bark and twigs, and beavers prefer trees ouch an
&open# cottenwoode poplar, willow, and members of the bitch
family. They also require deep water in order to build their'
lodges with underwater entrances and to provide a refuge from
disturbances. This is why they build dams in shallow streama. Ir
deeper bodies of water, they may forego the hard work of building
a dam.

once beavers populate a watershed, stream system# or other wetland:
areat they periodically will re-invade land from which they have
been eliminated by trapping or shooting. Recolonization is
likely, as long as the site continues to offer a hospitable
environment. A landowner who relies on firearms or traps should
anticipate an influx of beavers to his or her property.

Armed with the knowledge of what attracts beavers, a landowner Mal,
make the area less attractive to them by *thinking like a
beaver.a Ask "Why would beavers want to live here?" Then devise
ways to make food and/or deep water unavailable to them. Of
course, it would be unreasonable to cut down all trees and to
drain wetlands, but there are other practical, relatively simple
solutions.

One solution is to exclude animals from the land. This approach
is practical only for small areas such as pondso around which a
barrier can be created wi th a metal fence.

Where a conventional fence in not practical or desirable, It may
be possible to repel beavers with an electrified suspension fence,
which depends upon a high-voltage, low-amperage energy source suc@
as an automobile battery. A single wire, suspended approximatel%
I foot off the ground, Is connected to a power unit that transmd.
a pulsating electric charge. When a beaver touches the wire# it
receives a mild shock but Is otherwise unharmed. After several
encounters with this type of fence, a beaver will be conditioned
to avoid that location. The equipment needed to construct an
electrified fence can be purchased from a farm supply store.
Electrified fences are less expensive to build than conventional
fences, but they require more maintenance. Some systems can fail
In extremely dry conditions because an animal's feet may not be
sufficiently grounded. Another problem is that broken insulators
or wet, heavy weeds and grass can short the electric current,
Continued on ncxt page

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preventing it from flowing through the fence, thereby eliminating
its effectiveness.

Physical barriers can be used to shield ornamental trees. Each
tree can be wrapped in a band of hardware cloth or wire mesh that
extends approximately 3-1/2 feet above the ground. Recommended
mesh si:es vary from one-quartet inch to 1 inch. If the trees arc
in an area that is occasionally flooded, the cloth should extend
at least 2 feet above the high-water mark.

A diluted solution of creosote, available at most local garden
centers, has been found to reduce damage by gnawing beavers when
sprayed or painted on tree trunks. A landowner also can use a
homemade concoction to make trees or crops distasteful to
beavers. A favorite formula consists of 1 tablespoon of hot
popper sauce in a gallon of water which contains an additive that
promotes retention (such as Wiltq-Pruf or vapor-Gard). The
disadvantage of such a preparation is that it must periodically be
reapplied.

when planting trees near waterways frequented by beavers, avoid
their preferred food trees, listed above.

It Is futile to destroy a beaver dam. Beavers will begin
rebuilding one as soon as the landowner departs. it Is possible,
MEN however, to modify a beaver dam by placing a specially constructed
pipe through it so that the animals are unable to qateqm the flow of
Continued on next page

- 92

AUG-IM-91 7HU 14:M0 HSUS-MARO P.09
water. This device regulates the water level and prevents beaver
f ram expanding the size of a pond or impeding the flow Of -A
stream.

The pipe must stick out beyond the actual dam construction,
particularly on tho upstream side of the pond. A 10-foot to 40-
foot pipe will be required for most dams. A pipe that Is 8 inche
to 12 inches in diameter usually is adequate. Pipe aiia depends
on the Average volume of water flowing in the stream. Several
smaller diameter pipes may be substituted for one larger pipe.
Either galvanizedr plastice or aluminum irrigation pipe can be
used; A pipe also can be built with concrete reinforcing mesh
panels and welded wits mesh, or it can be fashioned from sheets c
metal# with the bottom side made of wire mesh. The pipe should b
placed at the same depth as the water level desired by the
landowner. Steel posts can be used to secure the pipe In
position.

The pipe should prevent beavers from obstructing the flow of wate:
or, at leastp should limit flooding to a tolerable depth. In man:
cases, beavers will find the shallow site unsuitable and will loo,
for a more favorable spot for their colony.
To prevent beavers from plugging the upstream opening in the pipe,
it should be fitted with a protective cover known as a "beaver
baffler.* One design for a baffler is a cone-shaped wire guard.
The base of the cone is anchored flat against the pipe. If
properly fittedr* this system looks like an arrow* Beavers will
attempt to dam the guard using twigs. They even may scoop mud
from the bottom of the pond and push It against the guard. The
shape of the guard should* prevent beavers from placing materials
flush against the mouth of the pipe. Although the beavers may be
partially successful in their efforts to block the pipe, enough
water usually will continue to flow to maintain the desired water
level. The animals soon will tire of their losing battle to bloc.
the flow of water and will move.

A secon4 type of' baffler also is designed for use on the mouth of
the pipe. it consists of an elbow bent downward at a 90-degree
angle and approximately one foot under the water surface. Beaver:i
cannot block the vertical intake opening of the elbow.

in Canada, biologists have improved on this concept. Before
placing the pipe through the beaver dam, they drill I-Lnch holesr
approximately 10 inches apart, along its entire length. some
biologists contend that it in necessary only to drill along the
first 10 feet of pipe an the upstream side of the dam. The water
flowing through the holes seems to confuse beavem which cannot
determine how or where to stop the flow of water. They often try
to plug the holes and ignore the mouth of the pipe. Once a pipe'.
has-been properly installed, a periodic inspection will ensure
that the water is flowincl properly.

Habitat alteration is a technique of beaver control that often Is
overlooked. On many streams and ponds, beavers can be encouraged
to relocate simply by removing food trees -- particularly young
willow and cottonwood trees -- and dam construction materials from
the water's edge. Beavers are limited in their ability to haul
Continued on next page

AUG-15-91 THU 14:50 HSUS-MARO

building materials across land. In the absence of a ready supply
of food or construction materials, they are unlikely to colonize a
stream or pond.
Some landowners insist on removing beavers. In such
circumstances, beavers can be captured &live and unharmed in cage
traps (check first with state wildlife officials for legal
restrictions). Because a beaver's powerful muscles and sharp
teeth can destroy a standard cage trapt several manufacturers have
designed sqpecqial.beaver traps that resemble a giant purse with
chain sides. This type of trap is expensive, costing
approximately $1q50, and it takes skill to properly and safely
set. if the trap is placed in too deep water, the animal may
drown, Anqd if tqhe trap is positioned incorrectly, the trap laws
may kill the animal. Contact a district game warden or county
extension agent for professional help in using cage traps to catch
beavers.

V
"in re-lanqdscaqping an area damaged by beavers# careful selection
of ornamental trees can prevent a recurrence of the problem.
Evergreens such as pine# first and spruce generally are safe from
assault. Because these trees are fast growing, they quickly
restore landscape that has been damaged by beaver activity.
The control of any wildlife species Is 'as much an art as a
science. Success in controlling beavers ultimately is related to
the skills and inventiveness of individuals. Tolerance for this
Industrious, often beneficial animal can make life easier for all
concerned. Nevertheless, if an occasional beaver problem must be
solved, the techniques outlined here offer the best hope for a
practical, permanent, and humane solution. q0

ter Art Evans graduated from The Humane Society of the United
qANqIMALCONq1q1MqI. 6qNSt&qte3' Animal Control Academy in 19q9q1, he was promoted to
8qVAqI2qDEMY director of Greene County Animal Control. Since thenp Evans has
NEWS overseen a number of Improvements in the facility's operations.
This column Is about you Previously chief of the animal-control department# located at 641
qDayton-xenqiqa Road* Xenia# OR 4qS3q65, Evans has used the skills and
-(he Acadomqy qorsduoqtel It knowledge he gained At the Academy to Increase the income of his
you've reseqlved a promotion, self-supporting agency to q0220,000 a year from q$q80#q00q0# increase
helped to AMID" local at
state animal 2qlqo8qgIs0qlqa0ql8qlqonq, the thqreqe-porsqon staff to eight full-time employees, and establish
Improved your community's now programs such as cruelty Investigation# cat control# pet
qaqn8qima04qkqoqn4qi8qm8ql program, or therapy, obedience training, and fund raising. 8qHis organization
had an 8qIqn4qtqeqiqvqoqt8qiqn2qg work. is the first in the state with authority to impound nuisance or
related qexpe8qdqeqnqcqe, writs to injured cats. The agency runs two shelters in Greene Cqount6qyt one
Shqe4qnqeqr Sqoqnsqo, The MSUS, in Fairborn, one iqn Xenia. It also picks up and redeems stray
12qMqI8qD8q0 8qL Stq. N.W, Washingq. dogs in Clinton County.
4qt0q^ 2qDC 2q28q1q12q14q?q,lqnc:4q1qudqs a
telephone number, please. "The key word Is 'professional,'" said Evans. 'At the Academy, I
became aware of the fact that I am not alone in the problems I
face, that solutions are available. I gained new pride and a
sense of organization through my training at the Academy that
allows me to overcome the negatives in my work and accent the
positive." 0q0

August 26, 1991

MS. Terri Fabean
Division of Fish and Wildlife
Delaware Department of Natural Resources and Environmental Control
Post Office Box 1401
Dover, Delaware 19903

Dear Ms. Fabean:

A friend aware of my long-standing interest in beavers sent me a copy of the
August 15th Delaware State News article on your statewide beaver management plan.
I'm writing to alert you to the existence of an organization devoted to protecting
beavers and finding creative ways for these wonderful animals to live in harmony with
man. The Beaver Defenders, based at the Unexpected Wildlife Refuge in Newfield,
New Jersey, can provide you with extensive information about beavers and their
contribution to the environment and suggestions for ways to resolve conflicts between
beavers and man. You can join for $10, which entitles you to receive a quarterly
newsletter filled with beaver facts, lore and letters from people who live near
lodges/dams. Contact:

Hope Sawyer Buyukrnihci
The Beaver Defenders
Unexpected Wildlife Refuge, Inc.
Post Office Box 765
Newfield, New Jersey 08344
(609) 697-3541

Recent editions of the newsletter mentioned the following resources you might
find useful:

Experiments reveal that the chemical repellent Ro-pel will sometimes
discourage beavers from eating trees. For more information, contact:
B1. Hilliker
Young Street
East Hampton, C`I' 06424

A booklet entitled "11ving with Beavers" by Dr. Tom Eveland is available
from the Alliance for Animals' Beaver Project. Contact:
Alliance for Animals - Beaver Project
Ill King Street - #26
Madison, Wisconsin 53703

A device known as a Beaver Baffle prevents them from damming up
culverts. Ibis inexpensive gadget resembles a cyUndrical chicken wire cap
which fits over the end of the pipe. Contact the Beaver Defenders for more
information.

PLEASE PLEASE PLEASE reconsider using underwater traps as an element
of your Beaver Management Plan. Drowning is a slow and horrible death for any
animal, especially one with the capacity to hold its breath underwater for half an hour
or more. Beavers can and do use their strong teeth to gnaw off their paws. Death
may follow from loss of blood, starvation, etc. Traps are cruel and inhumane. Ile
Beaver Defenders can tell you more, and may be able to put you in touch with
Delaware residents (and/or people from other states) who would welcome a beaver
colony on their land (people write to them asking to be put in touch with
organizations which relocate beavers).

Although the Beaver Defenders does not advocate moving beavers to zoos, I
have found that they make wonderful exhibits. A successful beaver exhibit captivates
both children and adults, and leads to greater appreciation of their contribution to
the environment. The Minneapolis-St.Paul Zoo has an excellent beaver facility. If
you cannot find homes for all of the beavers you relocate, you might wish to send
them to area zoos - it's better than death! Since beavers learn many of their skills
from their parents, zoos are a reasonable alternative for injured animals and youths
eparated from their colonies who are less able to cope in the wild. You should also
contact such groups as The Nature Conservancy to find homes for "problem" beavers.
s

As I'm sure you know, beavers are remarkable, trusting, intelUgent animals who
maintain strong family structures. Since they remain at their lodges until they are two
years old, learning skills and contributing to lodge and dam maintenance, food
gathering, and caring for younger animals, the impact of killing any single beaver,
especially a parent, has terrible ramifications for the entire colony. Could you please
send me a copy of your Beaver Management Plan? Thank you very much.

Elaine Van S. Carmichael
1411 Prince Street
Alexandria, Virginia 22314

Home: (703) 549-3912
Work: (703) 893-1560

cc: Hope Sawyer BuyukmihcL The Beaver Defenders

THE BaVER DEFENDERS SPRING 1991 - P. 7

THE BEAVER DEFENDERS
Membership Application

NAME

ADDRESS

Membership-subscription $10.00 per year. ?lease make checks payable to
Unexpected Wildlife Refuge. Contributions tax deductible. Amounts in
excess of actual membership will be considered a donation unless other-
wise specified.

-------------------------------------------------------------------------

EDUCATIONAL MATERIALS AVAILABLE FROM THE BEAVER DEFENDERS
(Proceeds to the Refuge. Postage extra. Please estimate.)

BEST OF THE BEAVER DEFENDERS. Selected articles, essays and poems,
illustrated with sketches, from the first 15 years of The Beaver
Defe=ders. 175 Pages- S10-00-

BEAVERSPRITE. By Dorothy Richards with HSB. 1977. Heart of the lakes
Publishing Co., Interlaken, KY. Story of Beaversprite, a sanctuary for
beavers and other wildlife. Recounts iichards' more than 40 years of
close association with beavers. $12.00.

IN BEAVER WORLD. By Enos A. Mills. First published in 1913. Republished
in 1989 by University of Nebraska Press, Lincoln, NE. A beaver classic.
Paperback, $10.00.

LILY POND, FOUR YEARS WITH A FAMILY OF BEAVERS. By Hope Ryden. William
Morrow & Co., 'TY. 1989. Close obervations end experiences with beavers
in a state park. 217-95.

PIAY, THE TRAPPER. 100.

WHAT WAVERS DO FOR OUR WATiMWAYS. 100.

YOU AND THE BEAVER and GOLDEN RULES OF CONSERVATION. Two leaflets Q 100 ea.

TIE STORY OF CHOPPER. 20o.

IN @040RIAM (Chopper). 100.

TWO BEAVER SONGS. 500 ea.

TRAPPED BEAVER POSTER. 500.

SAVE THE ANLIALSs 101 EASY THINCS YOU CAN DO. By Ingrid Newkirk. Warner
Books, KY. 1990. Paperback, $6.00 Postpaid.

"BEAVERS TURN WILDERNESS . . . INTO HAPPINESS."

ADMINISTRATIVE BUREAUS:
COMMONWEALTH OF PENNSYLVANIA ADMINISTRATION ..... 787-5670
A%8q" L AUTOMOTIVE AND
PROCUREMENT DIVISION 787-6594
ICENSE DIVISION 707-2004
ONN'S 6qL AN L
E 8qy PERSONNEL DIVISION 707-7836
WILDLIFE MANAGEMENT ... 787-5529
INFORMATION & EDUCATION 7874286
E' COMMISS2qF LAWENFORCEMENT 787-5740
LAND MANAGEMENT ....... 787-6818
REAL ESTATE D VISION .. 707-65U
2qWI ELMERMN AVENUE MANAGEMENT IN111ORMATION
HARRISBURG. PA 17110-9797 SYSTEMS ................. n74076

DATE: August 29, 1991

.SUBJECT: Delaware Beaver Management Plan

TO: William Meredith
Terri Fabean

FROM: Thomas S. Hardisky, Chief
Wildlife Data Base Division
Bureau of Land Management

Enclosed are my comments on your draf t Beaver Management
Plan as well as some material which you may find useful. This
document is one of the most thorough and well-prepared plans I
have seen on beavers. You've done an excellent job.

Please contact me if I can assist you further q(717-787-
1570).
_-

An Equal Opportunity Employer

Comments on Beaver Management Plan
Tom Hardisky
29 August 1991

Ref: p. 24

Relocated beavers will wander and attempt to return to their original colony. Expect caensiye
movements. V611th the exception of pregnant females, I believe that few muLsplanted beavers will remain in the
general vicinity of the release sde. Beavers are highly social and if scen mounds possessing unfamilin odors
exist at the release site, transplanted beavers will leave the area regardless of the sex or age of the relocated
beavers. Mortality would also be high during these random movcmentL

Relocation of pregnant females is an excellent way to establish beaver colonies in new area,
Transplanted females in their latter term of pregnancy generally will not move e=endveJy and will seek shelter
in preparation for birthing. Parturition dates vary but adult females captured from February-April would be
good candidates for relocation.

Personally, I would relocate a nuisance beaver as a last resort. Unless a beaver colony is highly
desirable in an area presently void of beavers, the time, expense, and limited succes of beaver relocation
outweighs its usefulness and practicality. Only where public attention is drawn to a specific site would I attempt
to relocate a beaver. Dispatch and disposal (burying) of the nuisance beaver on-site should be a viable (if not
preferred) alternative. The decision to relocate or dispatch the beaver should be flexible. Occasionally,
circumstances warrant immediate dispatch (for safety reasons).

Accurate sex and age information on removed beavers is extremely importanL Sexing beavers externally
can only be accomplished by determining the presence or absence of the bacuIum. This will require
immobilization of the beaver or some type of "squeeze" cage.

The stress associated with caprure@ immobilization, and transport will bigger nwvous reactions such as
gnawing on the metal cage. C2Lipped and broken teeth are common. occasional mortality should be cV=e&

000

Ref. p. 25

Ile leg snares, mentioned under Methods of Uve Trapping, would result in very limited trapping
These spring-activated snares are generally used for terrestrial animal capture and would be difficult
and time-consuming to set in aquatic habitats.

The use of cable snares for live capture of beavers should be considered. Trappers in the eastern U.S.
are unfamiliar with -na and lack confidence in their performance. However, cable snares have many
advantages over other live-capture methods.

Advantages of Using Snares:

- C;ost, SLOO each
. Lightweight
- Cannot injure trapper or unsuspecting traveler
- Do not kill beavers
- Risk of non-target catch is low
- Non-target catches may be released
- Low susceptibility to trap theft
. LOW susceptibility to rusting

Disadvantages of Snares:

- Heavy tie-down is required
- Cannot be reused after capture
- First-time users usually require instruction

Snares are practical, time-saving devices, especiaNy in remote areas. Since there is virtually no limit on
the number of snares which may be set, beaver problem areas may be heavily trapped resulting in faster, more
efficient beaver control.

As you probably kitow, rm sold on snares. I used snares in MississippL Florida, and Tennessee for
bobcats, black bears, and beavers and prefer them over steel traps and live traps. My trapping efficiency using
Ma was 11% (77 captmrc&f7O7 trapnights). Trapping success will vary by season with the best trapping period
falling between November and May. I did not routinely use No. 4 steel traps (underspring or longspring) due
to the time involved in preparing a drowning set. I have also had little success using this type of trap. If you
are interested in a snaring demonstration for your trappers/employees, let me know.

Ref. p. 26

Since ear tags are susceptible to loss especially on beavers, you may wish to mark beavers with tail tags.
Cattle ear tags work well for this purpose. The tail is not very vascular and consists of thick cartilage under the
scaly skin surface.

000

Unless telemetry is used, monitoring transplanted beavers will be extremely difficult. Telemetry is very
costly and would be difficult to justify in this situation. If telemetry is used, I would recommend a surgically-
implanted transmitter rather than a collar-mounted transmitter. An on-site inspection, as you have suggested,
is probably sufficieuL However, an extensive search may be needed to find evidence of beaver activity.

Refi p. 28

You may wish to implement a "hot spoe program for regulated beaver harvest. Landowners
experiencing beaver damage would enroll in the program and allow public beaver trapping on their land only.
Names and a0dresses of all cooperating landowners would be available to any interested trapper. The
landowner would be responsible for regulating the number of trappers permitted on his land. This "hot spoe

100

program would focus trapper effort on specific beaver problem areas. Disadvantages of this program include
law enforcement diffictilties and the lack of a to neighboring landowners who do not permit beaver
trapping-

Ref- p. 29

The inta portion of water control devices in beaver dams must be &ep@@ submerged to prevent
blockage by beavers. One very important behavior universally exhibited by beavers is their dam-building
response to the sound of running water. This behavior is thought to be innate (instinctive). Beavers will attempt
to plug water leakage on the upstream side of a dam, and even small whirlpools and swirls on the surface of the
water will stimulate the dam-building response. Water control structures or pipes must be positioned such that
the water ints1k is well below the water surface and does not create notice-able water currents. Multiple water
control devices should be installed to drain large water courses rather than installing I large drain. Beavers
generally will not attempt to block the water flowing out of the pipe on the downstream side of the dam. The
pipe need not extend several feet past the dam (see enclosed illustration).

Complete elimination of a beaver colony through trapping is unlikely. The best way to alleviate a severe
beaver problem is to heavily trap the area until you have no trapping success for several days. At this point,
begin to slowly lower the water level by breaking part of the dam each day. If beavers still exist in the area, they
will attempt to repair the dam and trapping should continue. If the dam is not repaireA continue to drain the
beaver pond to the desired water level and install a drainage device to maintain this level if beavers return.
Unrepaired dam breaks and lack of trapping success usually mean that the remidnin members of the beaver
colony have temporarily moved out of the area or that you have temporarily trapped out all the beavers in the
area.

Beaver ponds consisting of new dams (< 1 yr. old) and bank dons (no lodges) are characteristic of a
2-year-old pair of beavers who dispersed to a new area. Trapping can effectively eliminate this pair and the
associated beaver problem. Colonies with older dams and lodges generally support more beavers in different
age classes. Trapping in these areas controls population growth, but unless the dams are destroyed, complete
elimination through trapping is unlikely. Without sufficient water depth, beavers will leave the area and seek
more suitable habitat.

101

NTY ?-, ,.DELAWARE TRAPPERS ASSOCIATION
Cn
New Castle County Chapter

Wo,

August 29, 1991

Dear Ms. Terri Fabeant

Delaware Trapper Association respectfully request a limited
trapping season be implemented on beaver.

The season and method of catch could be closely regulated by
DNREC A system of tagging captured beavers similar to otter
would be useful in monitoring.

When considering beaver trapping in Delawarer the problem of
restrictive use of foothold traps must be addressedl The
leasing of state owned live traps may be a viable solution.
The costs of such traps makes them prohibitive.

We look forward to working with the Division on this most
important project. The beaver, landowners, Department of
Natural Resources and Environmental Control and the Delaware
Trappers Associatione will most certainly benefit from this
season.

Respectfully,

BH/psb

"Committed to Conservation and Education"

102

-10

Ms. Terri Fabean August 29, 1991
Division of Fish and Wildlife
Delaware Department of Natural Resources and Environmental Control
Post Office Box 1401
Dover, Delaware 19903

Dear Ms. Fabean:

When I wrote you about The Beaver Defenders a few days ago, I should have
mentioned another organization dedicated to ensuring that beavers and man can live
together in harmony. Leave it to the Beavers, a New Hampshire-based organization,
installs beaver baffles, pipes and dam diversions, facilitates beaver relocations, and
operates a sterilization program to enable beavers to remain in the wild at levels the
area can support. Contact: Leave it to the Beavers
Post Office Box 40
Plainfield, New Hampshire 03781

Ile booklet entitled "Living with Beavers" by Dr. Thomas E. Eveland, which
I recommended, is also available for one dollar from:

The Fund for Animal , Inc.
850 Sligo Avenue
Silver Spring, Maryland 20910
(301) 585-2591

Incidently, the rangers at Acadia National Park on Mt. Dessert Island in Maine
have used pipes with great success. rve enclosed a photocopy of a page from a recent
Beaver Defenders newsletter which includes an excerpt from "living with Beavers"
and a description of Leave it to the Beavers' efforts. I hope the information I've
provided has been helpful and encourage you to continue identifying creative solutions
to beaver mann ement issues which do not involve traps and other methods of killing.
Thank you for your efforts to help beavers.

Sincerely,

Elaine Van S. Carmichael
1411 Prince Street
Alexandria, Virginia 22314
Home: (703) 549-3912
Work: (703) 893-1560

cc: Hope Sawyer Bqyukmibci@ The Beaver Defenders

103

THE BEAVER DEFENDERS - SUMMER 1991 - P. 5
When Beavers and People Collide
by Dr. Thomas E. Eveland,
The Fund For Animals
We do have the technology to dams themselves to regulate ine wd- For example, with no controls on
either correct or prevent most of the ter levels. Later, they experimented the park's beavers, the estimated to-
problems created when beavers and with other techniques at road cul- tal population that would be reached
people collide. It is simply a matter verts. When all was said and done, in the near tuture cauSed some con-
of understanding the beaver, the their success was amazing. From cerns. The final outcome, however,
problem, and the methods used to 1980 to 1985 they recorciec an in- was quite different than expected.
change a bad situation into a good crease of 15 percent in the park's The park's beavers stabilized at only
one. When this knowledge is aP_ beaver population. Yet with the in- 60 percent of the estimated figure.
plied, the outcome can be very re- stallation of the experimental devi- Apparently this self regulation was
warding. ce5, the number of flooding caused by the following:
To site a case in point, let's take problems was reduced by more than 9 an apparent decrease in the fe-
a brief look at Gatineau Park, a large 75 percent. male reproduction rate when pop-
take-strewn area encompassing over In 1980, only 5 percent of the en- ulation density increases.
80,000 acres in Quebec with a high tire park was under long-term man the increased mortality rate of the
population of beavers. agement. By 1989, over 80 percent species during dry spells.
Gatineau had a serious beaver
problem which began in the early of the park was being managed for the use of lower quality sites
1960's. Road flooding and drain pipe long-term problem prevention. At which also reduces the species repro-
one site in the early 1980's more than cluction rates.
blockage were common and ac- 80 interactions were recorded for a So, with a progressive program of
counted for approximately 60 per- single year. Yet, only one year later, beaver problem control utilizing
cent of all beaver related complaints. after the installation of a drain and modern technology and the philos-
And for nearly 20 years the park without removal of the beavers, the ophy of natural resource manage-
managers tried to correct these pro- interactions had dropped to only ment combined with the self-regulat-
blems through dam breaking and four or five. Rather than call this a ing abilities of the beaver itself, Gat-
trapping. form of wildlife management, the ineau Park's conflicts between
In 1981, the park hired a contrac- park's employees deemed it "natu- beaver and man have been reduced
tor to deal with the unsolved beaver ral resource management", a more to near zero.
complaints. Realizing that the quick- appropriate namesake. Besides pro- (Excerpted with permission from
fix method was not solving the prob- ducing an almost total reduction in "Living with Beavers", a highly rec-
lems over the long-run, they wanted beaver-related problems, the park's ornmended paper on ways of solving
to try new and innovative techni- attempt at natural resource manage- problems. It is available for $1.00
ques. First, they began experiment- ment produced other results. from The Fund for Animals, Inc.,
ing with various pipes through the Suite LL2, 850 Sligo Ave., SHver
Spring, MD 20910)

NEW HAAIPSI-HRE HELPS BEAVERS:
by Steve Hackman
Leave it to the Beavers is a newly If you have a few acres with a A beaver pond could be a beauti-
formed group of people who would brook or stream, a low marshy area ful part of nature woven into your
like to see beaver living harmoni- with lots of alder and poplar, you landscape.
ously among us. Granted permission have the perfect spot for a lovely (Editor's notc: this new nonprofit
by the New Hampshire Fish and beaver pond. We hope you will con- group is funded solely by donations.
Game Department to start a beaver sider including one in your natural Organizers plan to use 98% of con.
sterilization program in New Hamp- landscape. You will be rewarded tributions for veterinarian fees for
shire, this small group is seeking many times over. Not only do beaver sterilizations. For more information
your assistance. Of prime impor- ponds have a special mystery, but contact Leave it to the Beavers, P.O.
tance right now is the need for relo- they do much for the ecosystem, en- Box 40, Plainfield, NH 03781.
cation sites for those beaver which riching the waterways and enhanc-
must be removed. In other instances, ing their surroundings to benfit birds
beaver could remain if beaver bafflers and other wildlife. If you feel your
or beaver pipes, or dam diversions land is capable of suporting only one
were used. In some circumstances, pair of beavers, an older pair of
the beaver could remain, provided beaver, already sterilized, could be
numbers were kept at a level suitable relocated to your property....
for the site.

104

HANDWRITTEN LETTER SUBMITTED BY JAMES D. METZGER,
WILMINGTON, DEL.

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107

Appendix 10

Active Participants in the Development of Delaware's Beaver
Management Plan - plan research and preparation; technical advice
and consultation; or plan review and written comment.

Terri Fabean, DFW/DNREC - Fish and Wildlife Scientist (planis
primary biologist, DCMP grant)

William H. Meredith, DFW/DNREC - Fish and Wildlife Program
Manager (DCMP task leader/liaison for Beaver Plan)

William C. Wagner II, DFW/DNREC - Division Director

H. Lloyd Alexander, DFW/DNREC - Program Administrator, Wildlife
Section
William R. Whitman, DFW/DNREC - Fish and Wildlife Scientist
(Beaver Committee chairman), Wildlife Section
E. Greg Moore, DFW/DNREC - Fish and Wildlife Program Manager,
Wildlife Section
Kenneth M. Reynolds, DFW/DNREC - Fish and Wildlife Program
Manager, Wildlife Section
Thomas W. Whittendale, DFW/DNREC - Fish and Wildlife Scientist,
Wildlife Section
Randall V. Cole, DFW/DNREC - Fish and Wildlife Scientist,
Wildlife Section
Wayne C. Lehman, DFW/DNREC - Fish and Wildlife Scientist,
Wildlife Section (regional wildlife biologist)
William L. Jones, DFW/DNREC - Fish and Wildlife Scientist,
Wildlife Section (regional wildlife biologist)
Robert D. Gano, DFW/DNREC - Fish and Wildlife Scientist, Wildlife
Section (regional wildlife biologist)
Stein H. Innvaer, DFW/DNREC - Fish and Wildlife Scientist,
Wildlife Section (regional wildlife biologist)

Major Rodney L. Harmic, DFW/DNREC - Enforcement Administrator,
Enforcement Section
Captain Roderick H. Burritt, DFW/DNREC - Fish and Wildlife Agent
(staff captain), Enforcement Section
Cpl. James C. Reynolds, DFW/DNREC Fish and Wildlife Agent,
Enforcement Section
Cpl. Paynter A. Lynch, DFW/DNREC Fish and Wildlife Agent
(retired), Enforcement Section
Richard L. Nutter, DFW/DNREC - Deputy Fish and Wildlife Agent,
Enforcement Section

Chester J. Stachecki, Jr., DFW/DNREC - Program Administrator,
Mosquito Control Section
Roger J. Wolfe, DFW/DNREC Fish and Wildlife Scientist, Mosquito
Control Section

Edwin H. Clark II, DNREC Secretary of the Delaware Department
of Natural Resources and Environmental Control

108

Andrew T. Manus, DSWC/DNREC - Deputy Division Director
Anthony P. Pratt, DSWC/DNREC - Program Administrator, Delaware
Coastal Management Program
Kevin C. Donnelly, DSWC/DNREC - Program Administrator,
Conservation Districts Operations
Richard T. Smith, DSWC/DNREC - Program Administrator, Drainage
Section

William Moyer, DWR/DNREC - Environmental Program Manager,
Wetlands and Aquatic Protection Branch
David E. Saveikis, DWR/DNREC - Environmental Scientist, Wetlands
and Aquatic Protection Branch

Ron Vickers, DPR/DNREC - Office of Nature Preserves/Natural Areas,
Technical Services Section
Leslie D. Trew, DPR/DNREC - Delaware Natural Heritage Inventory,
Technical Services Section
Keith Clancy, DPR/DNREC - Delaware Natural Heritage Inventory,
Technical Services Section
David Rothstein, DPR/DNREC - Delaware Natural Heritage Inventory,
Technical Services Section

David S. Small, I&E/DNREC - Chief, DNREC Information and
Education
Michael B. Mahaffie, I&E/DNREC - Public Information Officer

Timothy A. Kaden, FS/DOA - Forester Supervisor, Forestry Section,
Delaware Department of Agriculture

Paul D. Daly, USFWS - Refuge Manager, Bombay Hook/Prime Hook
National Wildlife Refuges

Thomas S. Hardisky, Chief, Wildlife Data Base Division,
Pennsylvania Game Commission

Steve Ruggeri, Wildlife Policy Director, Friends of Animals,
Inc., Norwalk, CT
Bob Reder, Field Investigator, The Humane Society of the United
States, Flanders, NJ
Elaine Van S. Carmichael, The Beaver Defenders, Alexandria, VA

Bud Holland, President, New Castle County Trappers Assoc.
(Delaware Trappers Association), Townsend, DE
James D. Metzger, Wilmington, DE

Jessie E. Anglin, DFW/DNREC - Word Processing Technician (all
typing of plan)

Doc. No. 40-05/91/09/01

109

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