[Federal Register Volume 74, Number 231 (Thursday, December 3, 2009)]
[Proposed Rules]
[Pages 63343-63366]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E9-28852]


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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[FWS-R6-ES-2008-0111] [MO 92210 50083 B2]


Endangered and Threatened Wildlife and Plants; 12-Month Finding 
on a Petition to List the Black-tailed Prairie Dog as Threatened or 
Endangered

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Notice of a 12-month petition finding.

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[[Page 63344]]

SUMMARY: We, the U.S. Fish and Wildlife Service (Service), announce our 
12-month finding on a petition to list the black-tailed prairie dog 
(Cynomys ludovicianus) as threatened or endangered under the Endangered 
Species Act of 1973, as amended (Act). After review of all available 
scientific and commercial information, we find that listing the black-
tailed prairie dog as either threatened or endangered is not warranted 
at this time. However, we ask the public to continue to submit to us 
any new information that becomes available concerning the status of, or 
threats to, the black-tailed prairie dog or its habitat at any time. 
This information will help us to monitor and conserve the species.

DATES: The finding announced in this document was made on December 3, 
2009.

ADDRESSES: This finding is available on the Internet at http://www.regulations.gov. Supporting documentation we used in preparing this 
finding is available for public inspection, by appointment, during 
normal business hours at the U.S. Fish and Wildlife Service, South 
Dakota Ecological Services Office, 420 South Garfield Avenue, Suite 
400, Pierre, SD 57501; telephone (605) 224-8693. Please submit any new 
information, materials, comments or questions concerning this finding 
to the above street address.

FOR FURTHER INFORMATION CONTACT: Pete Gober, Field Supervisor, U.S. 
Fish and Wildlife Service, South Dakota Ecological Services Office (see 
ADDRESSES section). If you use a telecommunications device for the deaf 
(TDD), call the Federal Information Relay Service (FIRS) at 800-877-
8339.

SUPPLEMENTARY INFORMATION:

Background

    Section 4(b)(3)(B) of the Endangered Species Act of 1973, as 
amended (Act) (16 U.S.C. 1531 et seq.), requires that for any petition 
to revise the Federal Lists of Endangered and Threatened Wildlife and 
Plants that contains substantial scientific and commercial information 
indicating that listing the species may be warranted, we make a finding 
within 12 months of the date of receipt of the petition. In this 
finding, we will determine that the petitioned action is: (a) not 
warranted, (b) warranted, or (c) warranted but the immediate proposal 
of a regulation implementing the petitioned action is precluded by 
other pending proposals to determine whether species are threatened or 
endangered, and expeditious progress is being made to add or remove 
qualified species from the Federal Lists of Endangered and Threatened 
Wildlife and Plants. Such 12-month findings must be published in the 
Federal Register.

Previous Federal Actions

    We received a petition dated October 21, 1994, from the 
Biodiversity Legal Foundation and Jon C. Sharps, to classify the black-
tailed prairie dog as a Category 2 candidate species. Category 2 
includes taxa for which information in our possession indicates that a 
proposed listing rule was possibly appropriate, but for which 
sufficient data on biological vulnerability and threats were not 
available to support a proposed rule. We reviewed the petition and on 
May 5, 1995, we concluded that the black-tailed prairie dog did not 
warrant Category 2 candidate status.
    On July 31, 1998, we received a petition from the National Wildlife 
Federation dated July 30, 1998, to list the black-tailed prairie dog as 
threatened throughout its range. On August 26, 1998, we received 
another petition to list the black-tailed prairie dog as threatened 
throughout its range from the Biodiversity Legal Foundation, Predator 
Project, and Jon C. Sharps. We accepted this second request as 
supplemental information to the National Wildlife Federation petition. 
On February 4, 2000, we announced a 12-month finding that issuing a 
proposed rule to list the black-tailed prairie dog was warranted but 
precluded by other higher priority actions (65 FR 5476), and the 
species was included in the list of candidate species. Two candidate 
assessments and resubmitted petition findings for the black-tailed 
prairie dog were completed on October 30, 2001 (66 FR 54303), and June 
13, 2002 (67 FR 40657). On August 18, 2004, we completed a resubmitted 
petition finding for the black-tailed prairie dog (69 FR 51217) 
concluding that listing the species was not warranted, and the species 
was removed from the candidate list. This removal was the result of new 
information regarding the amount of occupied habitat present throughout 
the species' range and a reevaluation of potential threats. Estimates 
from the 2004 finding were more accurate than those available during 
the earlier assessments and indicated nearly 3 times more occupied 
habitat was present than we originally believed. We concluded that the 
trends in the amount of occupied habitat did not support listing the 
species.
    On February 7, 2007, Forest Guardians and others filed a complaint 
challenging the decision to remove the black-tailed prairie dog from 
the candidate list. On August 6, 2007, we received a formal petition 
dated August 1, 2007, from Forest Guardians (now WildEarth Guardians), 
Biodiversity Conservation Alliance, Center for Native Ecosystems, and 
Rocky Mountain Animal Defense, requesting that we list the black-tailed 
prairie dog throughout its historical range in Arizona, Colorado, 
Kansas, Montana, Nebraska, New Mexico, North Dakota, Oklahoma, South 
Dakota, Texas, and Wyoming and in Canada and Mexico. The petitioners 
requested that, if the Service believes that Cynomys ludovicianus 
arizonensis is a distinct subspecies or population segment, we list it 
as threatened or endangered throughout its historical range. The 
petitioners also requested that the Service designate critical habitat 
for the species.
    The petition clearly identified itself as a petition and included 
the requisite identification information as required in 50 CFR 
424.14(a). We acknowledged receipt of the petition in a letter on 
August 24, 2007, and indicated that emergency listing of the black-
tailed prairie dog was not warranted. We also explained that we would 
not be able to address their petition until fiscal year 2009, due to 
existing court orders and settlement agreements for other listing 
actions. However, in fiscal year 2008, funding became available, and we 
began work on this petition finding. The plaintiffs withdrew their 
February 7, 2007, complaint on October 9, 2007.
    On March 13, 2008, WildEarth Guardians filed a complaint for 
failure to complete a 90-day finding on their August 1, 2007, petition. 
On July 1, 2008, a stipulated settlement and order was signed, in which 
we agreed to submit a 90-day finding to the Federal Register by 
November 30, 2008, and deliver a 12-month finding to the Federal 
Register by November 30, 2009. We published a 90-day finding for the 
black-tailed prairie dog in the Federal Register on December 2, 2008 
(73 FR 73211). Today's notice constitutes the 12-month finding on the 
August 1, 2007, petition to list the black-tailed prairie dog as 
threatened or endangered.

Species Information

    The black-tailed prairie dog is a member of the Sciuridae family, 
which includes squirrels, chipmunks, marmots, and several species of 
prairie dogs. Prairie dogs constitute the genus Cynomys. Taxonomists 
currently recognize five species of prairie dogs belonging to two 
subgenera, all in North America (Hoogland 2006a, pp. 8-9). The white-
tailed subgenus, Leucocrossuromys, includes Utah (C. parvidens), white-
tailed (C. leucurus), and Gunnison's prairie dogs (C. gunnisoni) 
(Hoogland 2006a, pp. 8-9).

[[Page 63345]]

The black-tailed subgenus, Cynomys, consists of Mexican (C. mexicanus) 
and black-tailed prairie dogs (Hoogland 2006a, pp. 8-9). Generally, the 
black-tailed prairie dog occurs east of the other four species in less 
xeric (dry) habitat (Hall and Kelson 1959, p. 365).
    The Utah and Mexican prairie dogs are currently listed as 
threatened (49 FR 22330, May 29, 1984) and endangered (35 FR 8491, June 
2, 1970), respectively. The Gunnison's prairie dog is currently a 
candidate species within the montane portion of its range (73 FR 6660, 
February 5, 2008). The Service is considering whether listing is 
warranted for the white-tailed prairie dog through a formal status 
review which is due to be submitted to the Federal Register by June 1, 
2010, under a court-approved settlement agreement.
    Research on the evolutionary divergence of the various taxa and 
populations of Cynomys indicates that the black-tailed prairie dog 
should be considered a monotypic species (a taxonomic group without 
lower level subdivisions) (Pizzimenti 1975, p. 64). Based on this 
information, we determined that the black-tailed prairie dog is a valid 
taxonomic species and a listable entity under the Act.
    We also investigated the petitioners' request that we list the 
subspecies Cynomys ludovicianus arizonensis if we found it to be a 
distinct subspecies. The best available information indicates that C. 
l. arizonensis is not a distinct subspecies (Pizzimenti 1975, p. 64). 
Pizzimenti (1975, p. 64) researched the evolutionary divergence of the 
various taxa and populations of Cynomys and concluded that the black-
tailed prairie dog should be considered a single monotypic species and 
that further subspecific differentiation was not supported due to the 
similarity of characteristics between purported subspecies. Later 
research on the genetic variability within and among populations of 
black-tailed prairie dogs in New Mexico also concluded that subspecies 
classification could not be supported (Chesser 1983, p. 326). 
Therefore, based on currently available information, we conclude that 
there are no distinct subspecies of black-tailed prairie dog.
    The black-tailed prairie dog is a burrowing, colonial mammal that 
is brown in color (Hoogland 2006a, pp. 8-9). Black-tailed prairie dogs 
are approximately 12 inches (in) (30 centimeters (cm)) in length and 
weigh 1 to 3 pounds (lbs) (500 to 1,500 grams (g)) (Hoogland 2006a, pp. 
8-9). Key characteristics distinguish the black-tailed prairie dog from 
other prairie dog species:
    (1) It has a longer (2 to 3 in (7-10 cm)) tail that is black-
tipped;
    (2) It is generally non-hibernating, except possibly in the 
northern and southern extremes of its range (Tuckwell and Everest 2009, 
p. 1; Truett et al. 2007, p. 10); and
    (3) It lives at lower elevations (2,300-7,200 feet (ft) (700-2,200 
meters (m))) (Hoogland 2006a, pp. 8-9). Overlap of the geographic 
ranges of the five species is minimal; consequently, species usually 
can be identified by locality (Hall and Kelson 1959, p. 365; Hoogland 
2006a, pp. 8-9).
    The black-tailed prairie dog is typically found in level or gently 
sloping short- and mixed-grass rangeland, primarily east of the Rocky 
Mountains (Koford 1958, p. 8). The species is an herbivore, consuming 
short-grasses such as buffalograss (Buchloe dactyloides) and blue grama 
(Bouteloua gracilis) as well as several forb species (Koford 1958, p. 
6). Prairie dogs also clip taller forage, without consuming it, to 
enhance their detection of predators (Hoogland 2006a, p. 15). Numerous 
species prey on the prairie dog including badger (Taxidea taxus), 
coyote (Canis latrans), black-footed ferret (Mustela nigripes), golden 
eagle (Aquila chrysaetos), and many other species of raptor (Hoogland 
1995, pp. 14-15).
    Several biological factors determine the reproductive potential of 
the black-tailed prairie dog. Females live 4 to 5 years, usually do not 
breed until their second year, and produce a single litter with an 
average of three pups annually (Hoogland 2001, p. 917; Hoogland 2006b, 
p. 29). Therefore, one female may produce zero to 15 young in its 
lifetime. While the species is not prolific in comparison to many other 
rodents, it is capable of rapid population increases after population 
reductions (Collins et al. 1984, p. 360; Pauli 2005, p. 17; Reeve and 
Vosburgh 2006, p. 144).
    The colonial nature of prairie dogs, especially the black-tailed 
prairie dog, is a noteworthy characteristic of the species (Miller et 
al. 1996, p. 20). Historically, black-tailed prairie dogs generally 
occurred in large complexes, containing multiple colonies that often 
contained thousands of individuals. These complexes covered hundreds or 
thousands of acres (ac), and extended for miles (Lantz 1903, p. 2671; 
Bailey 1905, p. 90; Bailey 1932, p. 122; Ceballos et al. 1993, p. 109). 
Currently, most colonies and complexes are much smaller.
    Colonial behavior offers an advantageous defense mechanism by 
aiding in the detection of predators and by deterring predators through 
mobbing behavior (Hoogland 1995, pp. 3-6). Colonial behavior also 
increases reproductive success through cooperative rearing of juveniles 
and aids parasite removal via shared grooming (Hoogland 1995, pp. 3-6). 
However, colonial behavior can increase the disadvantageous 
transmission of disease (Olsen 1981, p. 236; Biggins and Kosoy 2001, p. 
911; Antolin et al. 2002, p. 122). Plague is a disease that was 
introduced to North America and can spread from prairie dog to prairie 
dog through social behaviors such as grooming that transfers fleas 
carrying the disease. The disease can also be transmitted by pneumonic 
(airborne) or septicemic (blood) routes (see Threats Analysis, Factor 
C).
    An estimated 2.4 million ac (1 million hectares (ha)) of occupied 
habitat exists in a constantly shifting mosaic throughout an estimated 
283 million ac (115 million ha) of suitable habitat that occurs across 
a range of approximately 440 million ac (178 million ha). Historically, 
unsuitable habitat included wetlands, lands with steep slopes, lands 
with shallow or sandy soils, and wooded areas. More recently, tilled 
croplands and urban areas have also been considered to be only 
marginally suitable. Black-tailed prairie dog colonies may expand or 
contract from year to year (Koford 1958, p. 12). Whether a colony 
expands or contracts depends on a combination of several factors such 
as climate, poisoning, disease, and shooting. Prairie dogs may also 
disperse over considerably long distances and establish new colonies. 
Dispersal distances up to 6 miles (mi) (10 kilometers (km)) over a 
period of a few weeks have been documented (Knowles 1985, p. 37). 
Dispersal can maintain genetic diversity or restore it following plague 
epizootics (Trudeau et al. 2004, p. 206).
    The black-tailed prairie dog is considered a keystone species; that 
is, it is an indicator of diverse species composition within an 
ecosystem, and key to the persistence of that ecosystem (Kotliar et al. 
1999, pp.183, 185). The black-footed ferret, swift fox (Vulpes velox), 
golden eagle, and ferruginous hawk (Buteo regalis) use prairie dogs as 
a food source. The mountain plover (Charadrius montanus) and burrowing 
owl (Athene cunicularia) use habitat (burrows) created by prairie dogs 
(Kotliar et al. 1999, pp. 181-182). The most obligatory species of this 
group is the black-footed ferret, which has a clearly documented 
dependence on the prairie dog (Linder et al. 1972, pp. 23-24; Kotliar 
et al. 2006, pp. 55-57). Numerous other species share habitat

[[Page 63346]]

with prairie dogs, and rely on them to varying degrees (Kotliar et al. 
2006, pp. 54-55).

Species Range

    The historical range of the black-tailed prairie dog included 
portions of 11 States (Arizona, Colorado, Kansas, Montana, Nebraska, 
New Mexico, North Dakota, Oklahoma, South Dakota, Texas, and Wyoming), 
Canada, and Mexico (Hall and Kelson 1959, p. 365). This corresponds 
approximately with the Great Plains Physiographic Province, a zone of 
about 400 miles wide extending eastward from the Rocky Mountains. 
Approximately 395 million ac (160 million ha) of potential habitat are 
estimated to have existed across a range of approximately 440 million 
ac (178 million ha) (Black-footed Ferret Recovery Foundation (BFFRF) 
1999, p. 4; Ernst 2008, p. 2). The species currently exists in the same 
11 States, Canada, and Mexico, from extreme south-central Canada to 
northeastern Mexico and from approximately the 98\th\ meridian west to 
the Rocky Mountains. This very roughly corresponds to the western 
halves of North Dakota, South Dakota, Nebraska, Kansas, Oklahoma, and 
Texas and the eastern halves of Montana, Wyoming, Colorado, and New 
Mexico. The species was largely extirpated from Arizona before 1940 
(Arizona Game and Fish Department 1988, p. 22), and later described as 
extinct in that State (Cockrum 1960, p. 76). However, in 2008, the 
species was reintroduced into a small portion of its historical range 
in Arizona via translocations from wild populations in New Mexico (Van 
Pelt 2009, p. 41). Range contractions have occurred in the southwestern 
portion of the species' range in Arizona, New Mexico, and Texas through 
conversion of grasslands to desert shrub (Weltzin et al. 1997, pp. 758-
760; Pidgeon et al. 2001, p. 1773). In the eastern portion of the 
species' range in Kansas, Nebraska, Oklahoma, South Dakota, and Texas, 
range contractions are largely due to habitat destruction as a result 
of cropland development (BFFRF 1999, p. 1).

Population Estimates

    Most estimates of black-tailed prairie dog populations are based on 
estimates of the amount of occupied habitat (Facka et al. 2008, p. 
360), not numbers of individual animals. Biggins et al. (2006 p. 94) 
evaluated several methodologies for estimating prairie dog populations 
and concluded that counting actual numbers of prairie dogs is feasible 
only for small areas. Determining the actual population of a colony 
requires marking all colony residents. This method is reasonable for 
only a small number (less than five) of small colonies (each with less 
than 200 residents) because of the difficulty and impracticality of 
catching and marking all residents (Biggins et al. 2006, p. 102). 
Estimates of occupied habitat remain the best measure of estimating 
prairie dog abundance over a larger area. The actual number of prairie 
dogs present depends upon the density of animals in that locality. 
Density of prairie dogs varies depending on the season, ecological 
region, and climatic conditions, but typically ranges from 2 to 18 
individuals per ac (5 to 45 per ha) in early spring, before the 
emergence of young-of-the year (King 1955, p. 46; Koford 1958, pp. 10-
11; Hoogland 1995, p. 98; Fagerstone and Ramey 1996, p. 85). Prairie 
dog occupied habitat may expand locally during drought, with a 
concurrent decline in density, due to the extended foraging area needed 
to obtain food. Density can also vary spatially and temporally due to 
poisoning, plague, and recreational shooting as discussed in later 
sections.
    A more accurate large-scale estimate of occupied habitat can be 
derived by applying a correction factor for percent occupancy (the 
percent of habitat with burrows currently occupied by black-tailed 
prairie dogs) to an initial estimate. We can estimate percent occupancy 
via an on-site inspection of a portion of a survey area to confirm the 
presence of prairie dogs. This is particularly important in colonies 
that have been impacted by plague or poisoning. In these instances 
burrows remain but prairie dogs are absent. This unoccupied habitat 
should not be included in estimations of occupied habitat. We believe 
that occupied habitat is a reasonable measure to use in evaluating the 
persistence of the species inasmuch as comparisons involve millions of 
acres (hectares) and several-fold more millions of individual prairie 
dogs, whose numbers may fluctuate between and within years.
    We have relied on the best available estimates of occupied habitat 
from States, land managers, researchers, or other sources to evaluate 
distribution, abundance, and trends of prairie dog populations. Recent 
trends of prairie dog populations are an appropriate surrogate for 
evaluating the status of the species.
    Numerous estimates of black-tailed prairie dog occupied habitat are 
available, spanning a time period from 1903 to the present. In Table 1, 
we summarize historical estimates, estimates from a 1961 range wide 
survey, and the most recent available estimates. The 1961 estimates 
came from a Bureau of Sport Fisheries and Wildlife (BSFW) range wide 
survey that followed large-scale poisoning efforts and represent a low 
point in occupied habitat. Other estimates are from a variety of 
agencies and individuals as cited in Table 1. Additional estimates 
derived between 1961 and the most recent available estimates are also 
available in the Service's 2000 12-month finding and in the 2004 
species assessment that removed the black-tailed prairie dog from the 
candidate list (Service 2000, p. 98; Service 2004, p. 7).
    Some of these intermediate estimates are derived from field 
efforts, others are based on censuses by phone or mail, and the 
remainder are a result of desktop extrapolations. Desktop 
extrapolations used known estimates of occupied habitat that existed 
for portions of a state to derive a Statewide estimate for occupied 
habitat. These studies provide intermediate estimates of occupied 
habitat and additional information regarding trends.

                      Table 1. Occupied Habitat Estimates for the Black-tailed Prairie Dog
----------------------------------------------------------------------------------------------------------------
                                    Historical   ac     1961 (BSFW)  ac     Most Recent  ac      Year of Most
        State or Country                (ha)\A\             (ha)\A\              (ha)            Recent Survey
----------------------------------------------------------------------------------------------------------------
Arizona                           650,000 (263,000)   0                   8 (3)\3\            2008
                                   \1\
                                  1,396,000
                                   (565,000) \2\.
----------------------------------------------------------------------------------------------------------------
Colorado                          3,000,000           96,000              788,657 (319,158)   2006
                                   (1,214,000) \4\    (39,000)..........   \6\
                                  5,445,000
                                   (2,204,000) \2\.
                                  7,000,000
                                   (2,833,000) \5\.
----------------------------------------------------------------------------------------------------------------

[[Page 63347]]

 
Kansas                            2,000,000           50,000              173,593             2006
                                   (809,000) \7\      (20,000)..........   (70,251)\3\
                                  2,500,000
                                   (1,012,000) \5\.
                                  7,503,000
                                   (3,036,000) \2\.
----------------------------------------------------------------------------------------------------------------
Montana                           1,471,000           28,000              193,862             2008
                                   (595,000) \8\      (11,000)..........   (78,453)\9\
                                  6,000,000
                                   (2,428,000) \5\.
                                  10,667,000
                                   (4,317,000) \2\.
----------------------------------------------------------------------------------------------------------------
Nebraska                          6,000,000           30,000              136,991             2003
                                   (2,428,000) \5\    (12,000)..........   (55,438)\10\
                                  9,021,000
                                   (3,651,000) \2\.
----------------------------------------------------------------------------------------------------------------
New Mexico                        6,640,000           17,000              40,000              2003
                                   (2,687,000) \11\   (7,000)...........   (16,187)\12\
                                  8,950,000
                                   (3,622,000) \2\.
----------------------------------------------------------------------------------------------------------------
North Dakota                      2,000,000           20,000              22,597 (9,145)\13\  2006
                                   (809,000) \5\      (8,000)...........
                                  2,201,000
                                   (891,000) \2\.
----------------------------------------------------------------------------------------------------------------
Oklahoma                          950,000 (384,000)   15,000              57,677 (23,341)\3\  2002
                                   \5\                (6,000)...........
                                  4,625,000
                                   (1,872,000) \2\.
----------------------------------------------------------------------------------------------------------------
South Dakota                      1,757,000           33,000              630,849             2006
                                   (711,000) \14\     (13,000)..........   (255,296)\15\
                                  6,411,000
                                   (2,594,000) \2\.
----------------------------------------------------------------------------------------------------------------
Texas                             16,703,000          26,000              115,000             2006
                                   (6,759,000) \2\    (11,000)..........   (46,539)\3\
                                  57,600,000
                                   (23,310,000) \16\.
----------------------------------------------------------------------------------------------------------------
Wyoming                           5,786,000           49,000              229,607             2006
                                   (2,342,000) \2\    (20,000)..........   (92,919)\17\
                                  16,000,000
                                   (6,475,000) \5\.
----------------------------------------------------------------------------------------------------------------
        U.S. Total                78,708,000          364,000             2,388,841           ..................
                                   (31,852,000) \2\   (147,000).........   (966,730)
                                  102,583,000
                                   (41,514,000).
                                  (non-BFFRF
                                   citations) \B\.
----------------------------------------------------------------------------------------------------------------
Canada                            2,000 (1,000) \5\                       4,485 (1,815)\3\    2007
----------------------------------------------------------------------------------------------------------------
Mexico                            1,384,000                               36,561 (14,796)\3\  2006
                                   (560,000) \18\
----------------------------------------------------------------------------------------------------------------
        Range wide Total          80,094,000-                             2,429,887           ..................
                                   103,969,000                             (983,340) \1\
                                  (32,413,000-
                                   42,075,000).
----------------------------------------------------------------------------------------------------------------
\A\ Estimates rounded to the nearest thousand.
\B\ Low U.S. total estimate derived from the total of all BFFRF\2\ estimates (a single methodology described
  below) for each State. High total estimates were derived by adding all other estimates; in States with more
  than one other historical estimate (CO, KS, MT) the average was used.
\1\ Van Pelt 1998
\2\ BFFRF 1999
\3\ Koch 2009
\4\ Clark 1989
\5\ Knowles 1998
\6\ Odell et al. 2008
\7\ Lantz 1903
\8\ Flath and Ibach 2009
\9\ Hanauska-Brown 2009
\10\ Amack and Ibach 2009
\11\ Bailey 1932
\12\ Johnson et al. 2004
\13\ Knowles 2007
\14\ Linder et al. 1972
\15\ Vonk 2009
\16\ Bailey 1905
\17\ Grenier et al. 2007a
\18\ Ceballos et al. 1993

    Historical estimates of black-tailed prairie dog occupied habitat 
for a particular State are often quite variable. This is likely due to 
the imprecise survey methodologies used to derive early estimates. 
Additionally, some historical estimates were made after land conversion 
and poisoning had been initiated. If the average historical estimates 
(not including estimates from BFFRF 1999) in Table 1 for each State, 
Canada, and Mexico are summed, the range wide historical estimate of 
occupied habitat is approximately 104 million ac (42 million ha).
    The Black-footed Ferret Recovery Foundation (BFFRF) (1999, p. 4) 
addressed this variability in historical estimates by evaluating U.S. 
Geological Survey land use and land cover data throughout the range of 
the black-tailed prairie dog. The BFFRF assumed that suitable land 
cover types such as grassland and agricultural land were potential 
habitat for the species historically. Other land cover types such as 
forests, rocky areas, wetlands, and lands with excessive slopes were 
not considered. Whicker and Detling (1988, p. 778) estimated that 
black-tailed

[[Page 63348]]

prairie dogs occupied at least 20 percent of short- and mixed-grass 
prairies historically. BFFRF applied this 20 percent historical 
occupancy rate to its estimate of potential habitat to derive an 
estimate of approximately 79 million ac (32 million ha) of historically 
occupied habitat in the United States.
    A reasonable range wide estimate of historically occupied habitat 
for the black-tailed prairie dog that considers all historical 
estimates from Table 1 is approximately 80 to104 million ac (32 to 42 
million ha).
    In 1961, the BSFW, a predecessor agency of the Service, tabulated 
habitat estimates on a county-by-county basis throughout the range of 
all prairie dog species in the United States (BSFW 1961, p. 1). These 
estimates were completed by District Agents for BSFW who were familiar 
with remaining extant prairie dog populations. The survey was completed 
in response to concerns from within the agency regarding possible 
adverse impacts to prairie dogs following large-scale poisoning (Oakes 
2000, p. 167). These data provide an estimate for a single point in 
time when prairie dogs were reduced to very low numbers following a 
half century of intensive, coordinated government poisoning efforts.
    The petitioners questioned the use of the BSFW (1961) survey due to 
its brevity and the fact that it represented an extreme low point in 
black-tailed prairie dog occupied habitat. However, this survey has 
been cited in other seminal documents, including Leopold (1964, p. 38) 
and Cain et al. (1972, Appendix VIII). These latter two documents 
resulted in substantial changes in predator and rodent control policies 
in the United States, including a ban of Compound 1080, a highly toxic 
poison once widely used to control prairie dogs and other mammalian 
species. We agree that the early 1960s likely represented an extreme 
low in occupied habitat, but believe that the BSFW (1961) estimates of 
occupied habitat for the species are useful for trend analyses and 
represent the best available information for that time period.
    The most recent Statewide estimates vary in survey date from 2002 
to 2008 and include all black-tailed prairie dog occupied habitat known 
in a given State. The most current range wide estimate is approximately 
2.4 million ac (1 million ha) including Canada and Mexico. Trends for 
occupied habitat in the United States appear to be increasing from the 
low point of 364,000 ac (147,000 ha) in 1961. Statewide trends for the 
same period (1961 - present) range from nearly stable in North Dakota 
to an approximately 19-fold increase in South Dakota. The status in 
Arizona is currently indeterminate due to the recent reintroduction.
    We recognize that different methodologies were used at different 
times and in different locales for the various occupied habitat 
estimates. However, we believe that these estimates are the best 
available information and are comparable for the purpose of determining 
general population trends. Methods for determining occupied habitat 
have improved in recent years with the advent of tools such as aerial 
survey, satellite imagery, and Geographic Information Systems (GIS). 
Consequently, estimates that use these tools can be expected to be more 
accurate. Ground-truthing a percentage of the land surveyed to 
determine the percent of habitat occupied adds additional confidence to 
any large-scale estimate. States continue to refine their 
methodologies. A workshop is being planned in 2010 by the Western 
Association of Fish and Wildlife Agencies to further evaluate current 
survey methodologies for accuracy, statistical validity, cost, and 
other considerations. More detailed information regarding survey 
methodology, distribution, abundance, and trends for each State is 
provided as follows.
Arizona
    Survey methodology - The most recent survey by the Arizona Game and 
Fish Department in 2008 consisted of ground mapping, including ground-
truthing (Van Pelt 2009, p. 41). The small amount of occupied habitat 
enabled a detailed survey effort with ground-truthing throughout and a 
high degree of confidence in the estimate.
    Distribution - Historically, black-tailed prairie dog occupied 
habitat existed in extreme southeastern Arizona (Hall and Kelson 1959, 
p. 365). The species was extirpated from the State by approximately 
1940 (Arizona Game and Fish Dept. 1988, p. 22). In October 2008, the 
species was reintroduced on Las Cienegas National Conservation Area 
(Voyles 2009, pp. 1-2).
    Abundance - Historically approximately 650,000 ac (263,000 ha) (Van 
Pelt 1998, p. 1) to 1,396,000 ac (565,000 ha) (BFFRF 1999, p. 4) of 
black-tailed prairie dog occupied habitat existed in Arizona. The most 
recent survey was conducted in 2008 (Van Pelt 2009, p. 41) and percent 
occupancy was 100 percent. The most recent estimate is 8 ac (3 ha) of 
occupied habitat, following an October 2008 reintroduction on Las 
Cienegas National Conservation Area (Koch 2009, p. 7). The next survey 
is scheduled for 2009 (Van Pelt 2009, p. 41).
    Trends - Arizona contains approximately 1 percent of the potential 
habitat (Ernst 2008, p. 2) and less than 1 percent of currently 
occupied habitat in the United States. In 1961, no black-tailed prairie 
dog occupied habitat was found in Arizona (BSFW 1961, p. 1). Currently 
8 ac (3 ha) are estimated to occur (Koch 2009, p. 7). The recent date 
of reintroduction does not allow for any interpretation of trends. 
However, reintroduction of the species after approximately 70 years of 
absence in the State is notable.
Colorado
    Survey methodology - The most recent survey by the Colorado 
Division of Wildlife (CDOW) in 2006 consisted of aerial line-intercept 
surveys. The observers in airplanes fly line-intercepts and record the 
flight path and length of lines flown above black-tailed prairie dog 
colonies, then estimate the cumulative area of colonies from the 
percentage of the flight path intercepted by prairie dog colonies. CDOW 
attempted to ground-truth 10 percent of recorded colony intercepts 
(dependent upon landowner permission) (Odell et al. 2008, p. 1312). 
Improvements were made in previous survey methods, and results were 
published in the Journal of Wildlife Management (Odell et al. 2008, p. 
1312). However, petitioners and other parties expressed concerns that 
this study overestimated the amount of occupied habitat in Colorado 
(Knowles 2009, pp. 1-2; McCain 2009, p. 2; Miller 2009, pp. 1-3; 
Proctor 2009, p. 2; Reading 2009, pp. 1-9; Sidle 2009a, p. 1). Specific 
concerns included the method of designating active and inactive 
colonies, the absence of density evaluation in determination of 
occupancy, differences in occupancy levels compared to surrounding 
states, and the likelihood of this methodology being adopted by other 
states without further refinement.
    Estimates derived from large-scale surveys, such as those conducted 
at a Statewide level, are not as accurate as smaller-scale, more 
intensive surveys that can include ground-truthing of 100 percent of 
the habitat. This level of effort is not feasible in large surveys. 
Nearly all States, including Colorado, dedicate considerable resources 
to conducting surveys and refining their methodologies, which 
contribute to improved estimates in future surveys. The CDOW added 
ground-truthing to their most recent survey, which further refined 
their estimate of black-tailed

[[Page 63349]]

prairie dog occupied habitat. We consider the estimate provided by 
Odell et al. (2008, p. 1311) to constitute the best available 
information for Colorado.
    Distribution - Historically, black-tailed prairie dog occupied 
habitat existed in the eastern half of Colorado, east of the Front 
Range mountains (Hall and Kelson 1959, p. 365). Currently, distribution 
appears to be scattered in remnant populations throughout at least 75 
percent of the historical range (Van Pelt 2009, p. 14).
    Abundance - Historically, approximately 3,000,000 ac (1,214,000 ha) 
(Clark 1989, p. 17) to 7,000,000 ac (2,833,000 ha) (Knowles 1998, p. 
12) of black-tailed prairie dog occupied habitat existed in Colorado. 
CDOW completed the most recent survey in 2006 (Van Pelt 2009, p.14). 
Percent occupancy was 88 percent (Odell et al. 2008, p. 1311). Adjusted 
to account for 88 percent occupancy, the most recent estimate of 
occupied habitat is 788,657 ac (319,158 ha) (Odell et al. 2008, p. 
1311). The next survey is scheduled for 2011 (Van Pelt 2009, p. 14).
    Trends - Colorado contains approximately 8 percent of the potential 
habitat (Ernst 2008, p. 2) and approximately 33 percent of currently 
occupied habitat in the United States. In 1961, Colorado contained an 
estimated 96,000 ac (39,000 ha) of black-tailed prairie dog occupied 
habitat (BSFW 1961, p. 1). Currently, 788,657 ac (319,158 ha) of 
occupied habitat are estimated to occur in the state (Odell et al. 
2008, p. 1311). This amount represents an apparent eight-fold increase 
in occupied habitat since 1961.
Kansas
    Survey methodology - The Kansas Department of Wildlife and Parks 
conducted the most recent survey in 2006. It consisted of a combination 
of line transect (a survey along a straight path of standard width 
where the presence of appropriate habitat is recorded when observed) 
and interpretation of National Agriculture Imagery Program photographs 
(Van Pelt 2009, p. 15). No record of ground-truthing information was 
available. Because the State did not determine percent of habitat 
occupied, the estimate is less accurate than if they had ground-truthed 
a percentage of the lands surveyed and addressed percent occupancy. 
Nevertheless, the estimate is the most recent and best available 
information regarding the amount of black-tailed prairie dog habitat 
within the State.
    Estimates of percent occupancy provided in 10 recent Statewide 
surveys range from 73-89 percent, with an average of 81 percent (EDAW 
2000, p. 20; Sidle et al. 2001, p. 930; Bischof et al. 2004. p. 2; 
Johnson et al. 2004, p. 11; Knowles 2007, p. 2; Odell et al. 2008, p. 
1311; Emmerich 2009, p. 2; Hanauska-Brown 2009, p. 1). If the current 
Kansas estimate of 173,593 ac (70,251 ha) of occupied habitat were 
assumed to have 81 percent occupancy, this would equate to 140,610 ac 
(56,903 ha).
    Distribution - Historically, black-tailed prairie dog occupied 
habitat existed in the western two-thirds of Kansas (Hall and Kelson 
1959, p. 365). Currently, distribution appears to be scattered in 
remnant populations throughout at least 75 percent of the historical 
range (Van Pelt 2009, p. 16).
    Abundance - Historically, approximately 2,000,000 ac (809,000 ha) 
(Lantz 1903, p. 150) to 7,503,000 ac (3,036,000 ha) (BFFRF 1999, p. 4) 
of black-tailed prairie dog occupied habitat existed in Kansas. The 
Kansas Department of Wildlife and Parks completed the most recent 
survey in 2006 (Van Pelt 2009); it did not note percent occupancy. The 
most recent estimate is 173,593 ac (70,251 ha) (Van Pelt 2009, p. 15). 
The next survey is scheduled for 2009 (Van Pelt 2009, p. 15).
    Trends - Kansas contains approximately 10 percent of the potential 
habitat (Ernst 2008, p. 2) and approximately 7 percent of currently 
occupied habitat in the United States. In 1961, 50,000 ac (20,000 ha) 
of black-tailed prairie dog occupied habitat were estimated to occur in 
Kansas (BSFW 1961, p. 1). Currently 173,593 ac (70,251 ha) of occupied 
habitat are estimated to occur (Koch 2009, p. 7). This area represents 
an apparent three-fold increase since 1961.
Montana
    Survey methodology - The most recent survey conducted by the 
Montana Department of Fish, Wildlife and Parks in 2008 consisted of an 
aerial line intercept survey, patterned after Sidle et al. (2001, pp. 
929-931), White et al. (2005, pp. 266-268), and Odell et al. (2008, pp. 
1312-1313). No information was provided by the Montana Department of 
Fish, Wildlife and Parks regarding ground-truthing efforts in their 
preliminary report, although estimates for active and inactive colonies 
were provided, and percent occupancy was addressed (Hanauska-Brown 
2009, p. 1).
    Distribution - Historically, black-tailed prairie dog occupied 
habitat existed in the eastern two-thirds of Montana, with the 
exception of the northeastern corner of the State (Hall and Kelson 
1959, p. 365). Currently, distribution appears to be scattered in 
remnant populations throughout over 90 percent of the historical range 
(Van Pelt 2009, p. 20).
    Abundance - Historically, approximately 1,471,000 ac (595,000 ha) 
(Flath and Clark 1986, p. 67) to 10,667,000 ac (4,317,000 ha) (BFFRF 
1999, p. 4) of black-tailed prairie dog occupied habitat existed in 
Montana. The most recent survey was completed by the Montana Department 
of Fish, Wildlife and Parks in 2008 (Van Pelt 2009, p. 19). The percent 
of habitat occupied was 85 percent (Hanauska-Brown 2009, p. 1). 
Adjusted to account for 85 percent occupancy, the most recent estimate 
of occupied habitat is 193,862 ac (78,453 ha) (Hanauska-Brown 2009, p. 
1). The next survey is scheduled for 2011.
    Trends - Montana contains approximately 12 percent of the potential 
habitat (Ernst 2008, p. 2) and approximately 8 percent of currently 
occupied habitat in the United States. In 1961, an estimated 28,000 ac 
(11,000 ha) of black-tailed prairie dog occupied habitat occurred in 
Montana (BSFW 1961, p. 1). Currently, 193,862 ac (78,453 ha) of 
occupied habitat are estimated to occur (Hanauska-Brown 2009, p. 1). 
This area represents nearly a seven-fold increase since 1961.
Nebraska
    Survey methodology - The Nebraska Game and Parks Commission 
conducted the most recent survey in 2003, consisting of an aerial line 
intercept survey by county using variably spaced transects based on the 
estimated number of occupied acres in each county, with more transects 
in the more densely populated counties (Bischof et al. 2004, pp. 3-6). 
Methodology was patterned after Sidle et al. (2001, pp. 929-931). Based 
on the information provided regarding methodology, ground-truthing was 
not conducted; however, habitat was only classified as active 
(occupied) if black-tailed prairie dogs were seen (Bischof et al. 2004, 
pp. 3-6). Additional habitat was classified as ``possibly active'' if 
no prairie dogs were visible but evidence of recent activity was 
present.
    Distribution - Historically, black-tailed prairie dog occupied 
habitat existed throughout most of Nebraska west of the 97\th\ 
meridian, with the exception of most of the Sandhills region in the 
north-central portion of the State (Hall and Kelson 1959, p. 365). The 
current distribution is unknown, but the species occurs in less than 75 
percent of counties with historical records (Luce 2003, p. 17).

[[Page 63350]]

    Abundance - Historically, approximately 6,000,000 ac (2,428,000 ha) 
(Knowles 1998, p. 12) to 9,021,000 ac (3,651,000 ha) (BFFRF 1999, p. 4) 
of black-tailed prairie dog occupied habitat existed in Nebraska. The 
most recent survey was completed by the Nebraska Game and Parks 
Commission in 2003 (Amack and Ibach 2009, p. 1). The percent of habitat 
occupied was 74 percent (Bischoff et al. 2004, p. 6). Adjusted to 
account for 74 percent occupancy, the most recent estimate of occupied 
habitat is 136,991 ac (55,438 ha) (Amack and Ibach 2009, p. 1). An 
additional 102,828 ac (41,613 ha) were not verified and were classified 
as possibly active. No future surveys are scheduled at this time (Amack 
and Ibach 2009, p. 2).
    Trends - Nebraska contains approximately 11 percent of the 
potential habitat (Ernst 2008, p. 2) and approximately 6 percent of 
currently occupied habitat in the United States. In 1961, 30,000 ac 
(12,000 ha) of black-tailed prairie dog occupied habitat were estimated 
to occur in Nebraska (BSFW 1961, p. 1). Currently, 136,991 ac (55,438 
ha) of occupied habitat are estimated to occur (Amack and Ibach 2009, 
p. 1). This area represents nearly a five-fold increase since 1961.
New Mexico
    Survey methodology - New Mexico Department of Game and Fish 
conducted the most recent survey in 2003, which consisted of 
examination of digital orthophoto quadrangle imagery, followed by an 
effort to ground-truth 15 percent of recorded colonies (dependent upon 
landowner permission) (Johnson et al. 2004, pp. 3-4). Due to lack of 
permission in some cases, the actual amount of habitat ground-truthed 
was slightly less than 15 percent.
    Distribution - Historically, black-tailed prairie dog occupied 
habitat existed in the eastern and southwestern two-thirds of the State 
(Hall and Kelson 1959, p. 365). Currently, distribution appears to be 
scattered in remnant populations in 54 percent of the counties that had 
historical records (Van Pelt 2009, p. 28).
    Abundance - Historically, approximately 6,640,000 ac (2,687,000 ha) 
(Bailey 1932, pp. 14 and 16) to 8,950,000 ac (3,622,000 ha) (BFFRF 
1999, p. 4) of black-tailed prairie dog occupied habitat existed in New 
Mexico. The most recent survey was completed by the New Mexico 
Department of Game and Fish in 2003 (Johnson et al. 2004, p. 11). The 
percent of habitat occupied was 81 percent (Johnson et al. 2004, p. 
11). Adjusted to account for 81 percent occupancy, the most recent 
estimate of occupied habitat is 40,000 ac (16,187 ha) (Johnson et al. 
2004, p. 11). The next survey is underway and scheduled to be completed 
in 2009 (Van Pelt 2009, p. 27).
    Trends - New Mexico contains approximately 12 percent of the 
potential habitat (Ernst 2008, p. 2) and approximately 2 percent of 
currently occupied habitat in the United States. In 1961, 17,000 ac 
(7,000 ha) of black-tailed prairie dog occupied habitat were estimated 
to occur in New Mexico (BSFW 1961, p. 1). Currently, 40,000 ac (16,187 
ha) of occupied habitat are estimated to occur (Johnson et al. 2004, p. 
11). This area represents an apparent two-fold increase since 1961.
North Dakota
    Survey methodology - The most recent survey conducted by the North 
Dakota Game and Fish Department in 2006 consisted of aerial surveys, 
followed by an effort to ground-truth all active colonies that they 
were able to get landowner permission to visit and then map colonies 
using GPS (Knowles 2007, p. 3).
    Distribution - Historically, black-tailed prairie dog occupied 
habitat existed in the southwestern third of North Dakota, west of the 
Missouri River (Hall and Kelson 1959, p. 365). Currently, distribution 
appears to be scattered in remnant populations in 79 percent of 
counties that historically contained prairie dogs (Van Pelt 2009, p. 
24).
    Abundance - Historically, approximately 2,000,000 ac (809,000 ha) 
(Knowles 1998, p. 12) to 2,201,000 ac (891,000 ha) (BFFRF 1999, p. 4) 
of black-tailed prairie dog occupied habitat existed in North Dakota. 
The most recent survey was completed by the North Dakota Game and Fish 
Department in 2006 (Knowles 2007, p. 1). 89 percent of acres were 
occupied (Knowles 2007, p. 2). Adjusted to account for 89 percent 
occupancy, the most recent estimate of occupied habitat is 22,597 ac 
(9,145 ha) (Knowles 2007, p. 1). The next survey is scheduled for 2010 
(Van Pelt 2009, p. 24).
    Trends - North Dakota contains approximately 3 percent of the 
potential habitat (Ernst 2008, p. 2) and approximately 1 percent of 
currently occupied habitat in the United States. In 1961, 20,000 ac 
(8,000 ha) of black-tailed prairie dog occupied habitat were estimated 
to occur in North Dakota (BSFW 1961, p. 1). Currently, 22,597 ac (9,145 
ha) of occupied habitat are estimated to occur (Knowles 2007, p. 7). 
Occupied habitat has apparently remained relatively stable since 1961.
Oklahoma
    Survey methodology - The Oklahoma Department of Wildlife 
Conservation conducted the most recent survey in 2002, which consisted 
of interpretation of aerial maps and on-site ground-truthing with input 
from county game wardens (Van Pelt 2009, p. 30).
    Distribution - Historically, black-tailed prairie dog occupied 
habitat existed throughout approximately the western two-thirds of 
Oklahoma west of the 97\th\ meridian (Hall and Kelson 1959, p. 365). 
Currently, distribution is largely limited to the panhandle, although 
scattered remnant populations occur elsewhere throughout 87 percent of 
the historical range (Van Pelt 2009, p. 30).
    Abundance - Historically, approximately 950,000 ac (384,000 ha) 
(Knowles 1998, p. 12) to 4,625,000 ac (1,872,000 ha) (BFFRF 1999, p. 4) 
of black-tailed prairie dog occupied habitat existed in Oklahoma. 
Ground-truthing was conducted in the most recent survey completed by 
the Oklahoma Department of Wildlife Conservation in 2002 (Van Pelt 
2009, p. 30), however the percent of habitat occupied was not noted 
(Van Pelt 2009). The most recent estimate of occupied habitat is 57,677 
ac (23,341 ha) (Koch 2009, p. 7) based upon the 2002 survey (Van Pelt 
2009, p. 30). The next survey is scheduled for 2008 through 2009 (Van 
Pelt 2009, p. 30). We have not yet received any survey results.
    Trends - Oklahoma contains approximately 6 percent of the potential 
habitat (Ernst 2008, p. 2) and approximately 2 percent of currently 
occupied habitat in the United States. In 1961, 15,000 ac (6,000 ha) of 
black-tailed prairie dog occupied habitat were estimated to occur in 
Oklahoma (BSFW 1961, p. 1). Currently, 57,677 ac (23,341 ha) of 
occupied habitat are estimated to occur (Koch 2009, p. 7). This area 
represents a nearly four-fold increase since 1961.
South Dakota
    Survey methodology - The South Dakota Department of Game, Fish, and 
Parks conducted the most recent survey conducted in 2009 which 
consisted of interpretation of aerial photographs (Kempema et al. 2009, 
p. 2; Vonk 2009, p. 1). Ground-truthing was conducted on 25 percent of 
the surveyed area (Kempema et al. 2009, pp. 3, 5).
    Distribution - Historically, black-tailed prairie dog occupied 
habitat existed throughout the western three-fourths of the State (Hall 
and Kelson 1959, p. 365). Currently, distribution appears to be 
scattered in remnant

[[Page 63351]]

populations throughout 78 percent of the counties within the historical 
range (Van Pelt 2009, p. 34).
    Abundance - Historically, approximately 1,757,000 ac (711,000 ha) 
(Linder et al. 1972, p. 29) to 6,411,000 ac (2,594,000 ha) (BFFRF 1999, 
p. 4) of black-tailed prairie dog occupied habitat existed in South 
Dakota. The most recent survey was completed by the South Dakota 
Department of Game, Fish, and Parks in 2009. Percent occupancy was 93 
percent (Kempema et al. p. 5). Adjusted to account for 93 percent 
occupancy, the most recent estimate of occupied habitat is 630,849 ac 
(255,296 ha). The next survey is scheduled for 2011 (Van Pelt 2009, p. 
32).
    Trends - South Dakota contains approximately 9 percent of the 
potential habitat (Ernst 2008, p. 2) and approximately 26 percent of 
currently occupied habitat in the United States. In 1961, 33,000 ac 
(13,000 ha) of black-tailed prairie dog occupied habitat were estimated 
to occur in South Dakota (BSFW 1961, p. 1). Currently, 630,849 ac 
(255,296 ha) of occupied habitat are estimated to occur (Kempema et al. 
2009, p. 4; Vonk 2009, p. 1). This represents an apparent 19-fold 
increase since 1961.
Texas
    Survey methodology - The Texas Parks and Wildlife Department in 
2006 conducted the most recent survey which consisted of interpretation 
of Digital Orthoimagery Quarter Quadrangles (DOQQs) and ground-truthing 
(Van Pelt 2009, p. 37). The proportion of habitat that was ground-
truthed was not noted.
    Distribution - Historically, black-tailed prairie dog occupied 
habitat existed throughout approximately the northwestern one-third of 
Texas (Hall and Kelson 1959, p. 365). Currently, distribution appears 
to be scattered in remnant populations throughout 75 percent of the 
historical range (Van Pelt 2009, p. 38).
    Abundance - Historically, approximately 57,600,000 ac (23,310,000 
ha) (Bailey 1905, p. 90) to 16,703,000 ac (6,759,000 ha) (BFFRF 1999, 
p. 4) of black-tailed prairie dog occupied habitat existed in Texas. 
The Texas Parks and Wildlife Department completed the most recent 
survey in 2006 (Van Pelt 2009, p. 37). Percent occupancy was not noted. 
The most recent estimate of occupied habitat is 115,000 ac (46,539 ha) 
based upon the 2006 survey (Koch 2009, p. 7). The next survey is 
scheduled for 2010 (Van Pelt 2009, p. 37).
    Trends - Texas contains approximately 21 percent of the potential 
habitat (Ernst 2008, p. 2) and approximately 5 percent of currently 
occupied habitat in the United States. In 1961, 26,000 ac (11,000 ha) 
of black-tailed prairie dog occupied habitat were estimated to occur in 
Texas (BSFW 1961, p. 1). Currently, 115,000 ac (46,539 ha) of occupied 
habitat are estimated to occur (Koch 2009, p. 7). This area represents 
an apparent four-fold increase since 1961.
Wyoming
    Survey methodology - The Wyoming Game and Fish Department conducted 
the most recent survey in 2006 which consisted of delineation of colony 
boundaries from interpretation of DOQQs, followed by aerial survey to 
confirm status (Grenier et al. 2007b, pp. 115-116).
    Distribution - Historically, black-tailed prairie dog occupied 
habitat existed in the eastern half of Wyoming, east of the Rocky 
Mountains (Hall and Kelson 1959, p. 365). Currently, distribution 
appears to be scattered in remnant populations throughout at least 75 
percent of the historical range (Van Pelt 2009, p. 40).
    Abundance - Historically, approximately 5,786,000 ac (2,342,000 ha) 
(BFFRF 1999, p. 4) to 16,000,000 ac (6,475,000 ha) (Knowles 1998, p. 
12) of black-tailed prairie dog occupied habitat existed in Wyoming. 
The most recent survey was completed by the Wyoming Game and Fish 
Department in 2006 (Emmerich 2009, p. 2). Occupied habitat was 
categorized as healthy (87 percent) or impacted (13 percent) (Grenier 
et al. 2007a, p. 125. Adjusted to account for 87 percent occupancy, the 
most recent estimate of occupied habitat is 229,607 ac (92,919 ha) 
(Grenier et al. 2007a, p. 125). The next survey is scheduled for 2009 
(Van Pelt 2009, p. 39).
    Trends - Wyoming contains approximately 6 percent of the potential 
habitat (Ernst 2008, p. 2) and nearly 10 percent of currently occupied 
habitat in the United States. In 1961, 49,000 ac (20,000 ha) of black-
tailed prairie dog occupied habitat were estimated to occur in Wyoming 
(BSFW 1961, p. 1). Currently, 229,607 ac (92,919 ha) of occupied 
habitat are estimated to occur (Grenier et al. 2007a, p. 125). This 
area represents an apparent nearly five-fold increase since 1961.
Canada
    Survey methodology - The most recent survey was described as 
mapping with GPS (Koch 2009, p. 7). We do not have more detailed 
information concerning the methods used, including whether data was 
ground-truthed or corrected for occupancy.
    Distribution - Historically, black-tailed prairie dog occupied 
habitat existed in southernmost Saskatchewan (Hall and Kelson 1959, p. 
365). Currently, distribution is limited to remnant populations within 
the same range, primarily in Grasslands National Park (Tuckwell and 
Everest 2009, p. 2).
    Abundance - Historically, approximately 2,000 ac (809 ha) of black-
tailed prairie dog occupied habitat existed in Canada (Knowles 1998, p. 
12). Surveys are conducted every other year (Tuckwell and Everest 2009, 
p. 16). The most recent survey was completed in 2007 (Van Pelt 2009, p. 
64). Percent occupancy was not noted. The most recent estimate of 
occupied habitat is 4,485 ac (1,815 ha) based upon the 2007 survey 
(Koch 2009, p. 3).
    Trends - Canada represents the periphery of the black-tailed 
prairie dog's range and habitat has always been limited, but the amount 
of occupied habitat appears stable (Tuckwell and Everest 2009, p. 2).
Mexico
    Survey methodology - Recent survey techniques and extent of ground-
truthing efforts was not reported.
    Distribution - Historically, black-tailed prairie dog occupied 
habitat existed throughout the northern portion of the Mexican States 
of Chihuahua and Sonora (Hall and Kelson 1959, p. 365). Currently, 
distribution appears limited to remnant populations in a small area of 
northern Chihuahua (List 1997, p. 141).
    Abundance - Historically, approximately 1,384,000 ac (560,000 ha) 
of black-tailed prairie dog occupied habitat existed in Mexico 
(Ceballos et al. 1993, p. 109). The most recent survey was completed in 
2006 (Koch 2009, p. 3). Percent occupancy was not noted. The most 
recent estimate is 36,561 ac (14,796 ha) of occupied habitat (Koch 
2009, p. 3). The year of the next survey is not known.
    Trends - Mexico experienced a prolonged drought in recent years, 
which resulted in dramatic loss of vegetation, followed by a reduction 
in black-tailed prairie dog occupied habitat (Larson 2008, p. 87). The 
most recent estimate is 36,561 ac (14,796 ha) of occupied habitat in 
2006 (Koch 2009, p. 3). Occupied habitat appears to be declining in 
recent years.

Summary of Factors Affecting the Species

    We have considered all scientific and commercial information 
available in our files, including pertinent information received during 
this status review. We relied primarily on published, peer-

[[Page 63352]]

reviewed literature; information provided by affected state wildlife 
agencies; and information provided by the Western Association of Fish 
and Wildlife Agencies. We received more than 18,000 comment letters 
from individuals, agencies, organizations, and companies. Most were 
form letters that expressed support or opposition to listing the black-
tailed prairie dog. However, we cite several submissions that provided 
useful information in this finding. Much of the data refers to the 98 
percent of occupied habitat that occurs in the United States, but we 
include data on Canada and Mexico where available.
    Section 4 of the Act (16 U.S.C. 1533), and its implementing 
regulations (50 CFR 424) set forth procedures for adding species to, 
removing species from, or reclassifying species on the Federal Lists of 
Endangered and Threatened Wildlife and Plants. Under section 4(a)(1) of 
the Act, a species may be determined to be endangered or threatened 
based on any of the following five factors: (A) present or threatened 
destruction, modification, or curtailment of its habitat or range; (B) 
overutilization for commercial, recreational, scientific, or education 
purposes; (C) disease or predation; (D) the inadequacy of existing 
regulatory mechanisms; or (E) other natural or manmade factors 
affecting its continued existence.
    We addressed the potential threats discussed in the petition under 
the most appropriate factor; however, we recognize that several 
potential threats might be considered under more than one factor. For 
example, poisoning can affect habitat (Factor A), and can be affected 
by state and Federal regulatory mechanisms (Factor D), but is primarily 
addressed in this finding under other factors (Factor E). In making 
this finding, information pertaining to the black-tailed prairie dog , 
in relation to the five factors provided in section 4(a)(1) of the Act 
is discussed below.

Factor A. The Present or Threatened Destruction, Modification, or 
Curtailment of its Habitat or Range

    Some black-tailed prairie dog habitat has been destroyed, modified, 
or curtailed by:
    (1) conversion of native prairie habitat to cropland;
    (2) urbanization;
    (3) oil, gas, and mineral extraction;
    (4) habitat loss caused by loss of prairie dogs; and
    (5) livestock grazing, fire suppression, and weeds.
    In some instances, black-tailed prairie dog habitat continues to be 
impacted by these same stressors. The Black-tailed Prairie Dog 
Conservation Team developed conservation plans that address issues of 
habitat loss. Each is discussed below.
Conversion of native prairie habitat to cropland
    The present or threatened destruction of habitat due to cropland 
development affects portions of the black-tailed prairie dog's range. 
Regular cultivation precludes burrow development by the species. This 
practice is the most substantial cause of habitat destruction that we 
are able to quantify. Conversion of native prairie to cropland has 
largely progressed across the species' range from east to west. The 
most intensive agricultural use is in the eastern portion of the black-
tailed prairie dog's range, in portions of North Dakota, South Dakota, 
Nebraska, Kansas, Oklahoma, and Texas, where higher rainfall amounts 
and generally better soils result in greater agricultural production. 
Land with the highest potential for traditional farming uses was 
converted many years ago. Consequently, the present and future 
destruction of habitat through cropland conversion is likely much less 
than in the early days of agricultural development in the Great Plains.
    A detailed assessment using the National Land Cover Dataset 
determined that there are approximately 110 million ac (45 million ha) 
of cropland and 283 million ac (115 million ha) of rangeland within the 
species' range at present (Ernst 2008, pp. 10-19). When the 2.4 million 
ac (1 million ha) of currently occupied habitat is contrasted with the 
283 million ac (115 million ha) of rangeland, it appears that 
sufficient potential habitat still occurs within the range of the 
species in the United States to accommodate large expansions of prairie 
dog populations. These areas could be colonized over time by expansion 
of existing colonies if the landowners and public sentiment allows.
    In recent years, ethanol production from corn has expanded in the 
United States (Westcott 2007, p. 1). However, most corn is cultivated 
east of the range of the black-tailed prairie dog (Westcott 2007, p. 
3). Additionally, the increase in corn production largely occurs by 
adjusting crop rotations between corn and soybeans (Westcott 2007, p. 
7). We do not anticipate that increased ethanol production will result 
in a substantial loss in the species' occupied or potential habitat.
    The current status of the black-tailed prairie dog, as indicated by 
increasing trends in the species' occupied habitat since the early 
1960s, suggests that the present or threatened destruction of habitat 
due to cropland development is not a limiting factor for the species.
Urbanization
    The present or threatened destruction of habitat due to 
urbanization affects portions of the black-tailed prairie dog's range, 
particularly east of the Front Range in Colorado. However, in a 
Statewide or range wide context, loss of habitat due to urbanization is 
not substantial. In Colorado, approximately 502,000 ac (203,000 ha) of 
urban lands and 21.6 million ac (8.8 million ha) of rangeland occur 
within the species' range (Ernst 2008, pp. 10-11). This equates to 
approximately 2 percent of potential habitat lost to urbanization in 
Colorado. Throughout the United States, approximately 2.4 million ac (1 
million ha) of urban lands occur within the species' historic range 
(Ernst 2008, pp. 10-18), while approximately 283 million ac (115 
million ha) of rangeland exist within the species' range. This equates 
to less than 1 percent of potential habitat lost to urbanization in the 
United States. A very small percentage of potential prairie dog habitat 
has been lost to urbanization. As a consequence, it appears that 
sufficient potential habitat still occurs within the range of the 
species, including Colorado, to accommodate existing or large 
expansions of prairie dog populations, even if some local prairie dog 
populations may be lost to urbanization in the future.
    The current status of the black-tailed prairie dog, as indicated by 
increasing trends in the species' occupied habitat since the early 
1960s, indicates that the present or threatened destruction of habitat 
due to urbanization is not a limiting factor for the species.
Oil, gas, and mineral extraction
    The present or threatened curtailment of habitat due to oil, gas, 
and mineral extraction may affect portions of black-tailed prairie dog 
occupied habitat; however, we have no information that quantifies these 
impacts. Qualitative information was submitted on behalf of the 
Petroleum Association of Wyoming, the Public Lands Advocacy, the 
Montana Petroleum Association, the New Mexico Oil and Gas Association, 
Oklahoma Independent Petroleum Association, and the Independent 
Petroleum Association of Mountain States. Mapping in colonies within 
oil and gas development areas in Wyoming indicates increased prairie 
dog occupancy in these areas (Sorensen et al. 2009, pp. 5-6). Although 
we have not confirmed this conclusion, the current status of the black-
tailed prairie dog, as

[[Page 63353]]

indicated by increasing trends in the species' occupied habitat since 
the early 1960s, indicates that the present or threatened curtailment 
of habitat due to energy development is not a limiting factor for the 
species in Wyoming or elsewhere throughout its range.
Habitat loss caused by loss of prairie dogs
    The present or threatened modification of habitat due to the 
extirpation of black-tailed prairie dogs may affect portions of the 
species' range. The petitioners theorized that the loss of prairie dogs 
from their habitats may create a negative feedback loop, resulting in 
their habitat becoming less suitable. Documentation of the species' 
effects on habitat is mixed. In some instances, prairie dogs may have a 
positive effect on habitat (Koford 1958, pp. 43-62; Kotliar et al. 
1999, p. 178; Johnson-Nistler et al. 2004, p. 641; Lantz et al. 2006, 
p. 2671). Positive effects have been particularly notable in the 
southwestern portion of the species' range where the foraging and 
clipping habits of prairie dogs destroy seedlings of undesirable shrub 
and tree species that might otherwise invade and eventually convert 
grasslands to scrublands. The aeration of soil from burrow construction 
may increase the growth of grasses (Koford 1958, pp. 43-62; Davis 1974, 
p. 156; Fagerstone and Ramey 1996, p. 89; List 1997, p. 150; Weltzin et 
al. 1997, pp. 758-760). Prairie dogs may also have a negative habitat 
effect by reducing grass species and causing conversion to less 
desirable forb species (Koford 1958, pp. 43-62; Bonham and Lerwick 
1976, p. 225; Klatt and Hein 1978, p. 316; Fagerstone and Ramey 1996, 
p. 88; Johnson-Nistler et al. 2004, p. 641). However, the current 
status of the black-tailed prairie dog, as indicated by increasing 
trends in the species' occupied habitat since the early 1960s, 
indicates that the present or threatened modification of habitat due to 
the presence or absence of prairie dogs on their habitat is not a 
limiting factor for the species.
Livestock grazing, fire suppression, and weeds
    The present or threatened modification of habitat due to livestock 
grazing, fire suppression, and weeds may affect portions of the black-
tailed prairie dog's range. Nonnative plant species may increase as a 
result of overgrazing and in the absence of fire, may modify the 
habitat. However, the impact of plant composition on habitat 
suitability for prairie dogs is contradictory. Some studies suggest 
that prairie dogs cause deterioration in forage quality, while others 
contend that livestock grazing causes a deterioration in forage quality 
(Koford 1958, pp. 43-62; Uresk et al. 1981, p. 200; Cerovski 2004, p. 
101; Vermeire et al. 2004, p. 691; Detling 2006, p. 115). Available 
information indicates that livestock grazing typically encourages 
black-tailed prairie dog expansion by maintaining vegetation at a lower 
height that improves visibility for prairie dogs (Osborn and Allan 
1949, p. 330; Koford 1958, p. 68; Snell and Hlavachick 1980, p. 240; 
Uresk et al. 1981, p. 200; Hubbard and Schmitt 1983, p. 30; Marsh 1984, 
p. 203; Snell 1985, p. 30; Groombridge 1992, p. 290; U.S. Forest 
Service 1995, p. 5; Fagerstone and Ramey 1996, p. 88; Wuerthner 1997, 
pp. 460-461; U.S. Forest Service 1998, p. 4; Forest 2005, p. 528; 
Andelt 2006, p. 131).
    The current status of the black-tailed prairie dog, as indicated by 
increasing trends in the species' occupied habitat since the early 
1960s, indicates that the present or threatened modification of habitat 
due to livestock grazing, fire suppression, or weeds is not a limiting 
factor for the species.
The Black-tailed Prairie Dog Conservation Assessment and Strategy
    Following the 1998 petitions to list the black-tailed prairie dog, 
a group of representatives from each State within the historical range 
of the species formed the Black-tailed Prairie Dog Conservation Team. 
The team intended to reduce threats to the species and increase the 
amount of habitat occupied by the species. The Team developed ``The 
Black-tailed Prairie Dog Conservation Assessment and Strategy'' (Van 
Pelt 1999), which initiated development of ``A Multi-State Conservation 
Plan for the Black-tailed Prairie Dog, Cynomys ludovicianus, in the 
United States'' (Multi-State Plan) (Luce 2002).
    The purpose of the Multi-State Plan was to provide adaptive 
management goals for future prairie dog management within the 11 
States. The Multi-State Plan identified the following minimum 10-year 
target objectives:
    (1) maintain at least the currently occupied acreage of black-
tailed prairie dog habitat in the United States;
    (2) increase occupied habitat to at least 1,693,695 ac (685,414 ha) 
in the United States by 2011;
    (3) maintain at least the current occupied acreage in the two 
complexes greater than 5,000 ac (2,023 ha) that then occurred on and 
adjacent to Conata Basin-Buffalo Gap National Grassland, South Dakota, 
and Thunder Basin National Grassland, Wyoming;
    (4) develop and maintain a minimum of 9 additional complexes 
greater than 5,000 ac (2,023 ha), with each State managing or 
contributing to at least one complex greater than 5,000 ac (2,023 ha) 
by 2011;
    (5) maintain at least 10 percent of total occupied acreage in 
colonies or complexes greater than 1,000 ac (405 ha) by 2011; and
    (6) maintain distribution over at least 75 percent of the counties 
in the historical range, or at least 75 percent of the historical 
geographic distribution.
    Objectives 1, 2, and 3 have been achieved. Objectives 4, 5, and 6 
have not yet been demonstrated in all States. The progress of 
individual states in achieving these objectives is described in more 
detail under Factor D.
    The States also agreed to draft Statewide management plans for the 
black-tailed prairie dog. The States approve their own Statewide 
management plans. Colorado and Wyoming have finalized grassland 
conservation plans that support and meet the objectives of the Multi-
State Plan. South Dakota has a finalized management plan that supports 
and meets the Multi-State Plan's objectives, but reserves the right to 
preserve its own management authority and identify its own goals and 
objectives. Kansas, Oklahoma, and Texas have finalized management plans 
that support the Multi-State Plan objectives, but have not yet met all 
of those objectives. Montana, New Mexico, and North Dakota have 
finalized management plans that do not support or meet all of the 
objectives of the Multi-State Plan. Arizona has a draft plan that 
supports the Multi-State Plan's objectives, but their Wildlife 
Commission did not approve it. Nevertheless, Arizona continues to work 
toward the Multi-State Plan's objectives. Nebraska has a draft plan 
that supports the Multi-State Plan objectives, but it its Wildlife 
Commission did not approve it. In Nebraska, work toward the Multi-State 
Plan's objectives has been halted.
    As a result of the development of the Multi-State and Statewide 
management plans, state wildlife agencies are surveying and monitoring 
black-tailed prairie dogs on a more regular basis. These efforts will 
enable the States to monitor the status of the black-tailed prairie dog 
and the progress of the conservation programs.
Summary of Factor A
    Cropland conversion, urbanization, energy development, conversion 
to scrubland in the absence of prairie dogs, and invasion of non-native 
species all occur within the historical range of the black-tailed 
prairie dog, and will likely

[[Page 63354]]

continue to occur in the future. However, when the approximately 2.4 
million ac (1 million ha) of currently occupied habitat is contrasted 
with the extant 283 million ac (115 million ha) of rangeland, it 
appears that sufficient potential habitat still occurs within the range 
of the species in the United States to accommodate prairie dog 
expansions over time despite some habitat loss from these stressors. 
Since the early 1960s, occupied habitat has increased in every State. 
The species' occupied habitat in the United States is estimated to have 
increased by over 600 percent from 1961 until the present time. This 
increase has occurred despite continued impacts to the species' habitat 
and impacts from other factors. The current status of the black-tailed 
prairie dog, as indicated by increasing trends in the species' occupied 
habitat since the early 1960s, indicates that the present or threatened 
destruction, modification, or curtailment of habitat or range is not a 
limiting factor for the species. The most significant impact to the 
species' habitat that we are able to quantify is habitat loss due to 
cropland conversion, and the rate of conversion is likely much less 
than in the early days of agricultural development in the Great Plains. 
Consequently, we do not anticipate that impacts from habitat loss are 
likely to negatively impact the status of the species in the 
foreseeable future.
    We conclude that the best scientific and commercial information 
available indicates that the black-tailed prairie dog is not now, or in 
the foreseeable future, threatened by the present or threatened 
destruction, modification, or curtailment of its habitat or range to 
the extent that listing under the Act as a threatened or endangered 
species is warranted at this time. Abundant suitable habitat in the 
form of rangeland exists and is not a limiting factor for the species. 
The present or threatened modification of prairie dog habitat presented 
by sylvatic plague is addressed under Factor C, and the present or 
threatened curtailment of prairie dog habitat presented by poisoning is 
addressed under Factor E.

B. Overutilization for Commercial, Recreational, Scientific, or 
Educational Purposes

    Recreational shooting of black-tailed prairie dogs can reduce 
population densities, cause behavioral changes, diminish reproduction 
and body condition, increase emigration, and cause extirpation in 
isolated circumstances (Stockrahm 1979, pp. 80-84; Knowles 1988, p. 54; 
Vosburgh 1996, pp. 13, 15, 16, and 18; Vosburgh and Irby 1998, pp. 366-
371; Pauli 2005, p. 1; Reeve and Vosburgh 2006, p. 144). This may be 
due to the colonial nature of prairie dogs, their sensitivity to social 
disruption, and the intense nature of some recreational shooting. 
However, available information from several of the same studies 
indicates that populations can also often recover from very low numbers 
following intensive shooting (Knowles 1988, p. 54; Vosburgh 1996, pp. 
16, 31; Dullum et al. 2005, p. 843; Pauli 2005, p. 17; Cully and 
Johnson 2006, pp. 6-7). Based on the research cited above, it appears 
that a typical scenario is either: (1) once populations have been 
reduced, shooters go elsewhere and populations recover; or (2) 
continued shooting maintains reduced population size at specific sites. 
Some landowners maintain prairie dog populations and derive income from 
charging people for recreational shooting. Monetary gain from shooting 
fees may motivate landowners to preserve prairie dog colonies for 
future shooting opportunities. This is currently an alternative to 
eradicating them by poisoning (Vosburgh and Irby 1998, pp. 366-371; 
Reeve and Vosburgh 2006, pp. 154-155).
    Pauli (2005) studied five colonies not exposed to shooting and 
compared population effects with five colonies where shooting occurred. 
He found that in the colonies with shooting, reproductive output 
decreased by 76 percent from 2003-2004 on the shot colonies (Pauli 
2005, p. 29). However, all colonies but one expanded from 2003-2004, 
although expansion was greater in control colonies (49.6 percent) than 
in colonies where shooting occurred (25.0 percent) (Pauli 2005, p. 17). 
The colony that did not expand was a control colony that experienced 
plague (Pauli et al. 2006, p. 77). A second paper on the same research 
project noted a decline in reproductive output in colonies with 
shooting, of 82 percent from 2003-2004, but did not discuss colony 
expansion (Pauli and Buskirk 2007a, p. 1228).
    Recreational shooting may increase the potential for lead poisoning 
in predators and scavengers consuming shot prairie dogs (Reeve and 
Vosburgh 2006, p. 154). This risk may extend to prairie dogs, which 
have occasionally been observed to cannibalize carcasses (Hoogland 
1995, p. 14). Recreational shooters primarily use bullets designed to 
expand on impact and rarely remove carcasses. In one study, expanding 
bullets left an average of 3.426 grains (228.4 milligrams (mg)) of lead 
in a prairie dog carcass, while non-expanding bullets averaged 0.297 
grains (19.8 mg) of lead (Pauli and Buskirk 2007b, p.103). The authors 
noted that the amount of lead in a single prairie dog carcass shot with 
an expanding bullet is potentially sufficient to acutely poison 
scavengers or predators, and may provide an important portal for lead 
entering wildlife food chains. A wide range of sublethal toxic effects 
are also possible from smaller quantities of lead (Pauli and Buskirk 
2007, p.103).
    Black-tailed prairie dogs are occasionally collected for the pet 
trade, plague research, and zoo displays. However, we have no 
information indicating any adverse effects resulting from possible 
overutilization for commercial (pet trade), scientific (plague 
research), or educational (zoo displays) purposes.
Summary of Factor B
    Recreational shooting of prairie dogs can cause localized effects 
on a population. However, literature documenting effects from shooting 
of prairie dogs also frequently describes subsequent rebounds in local 
populations. Extirpations due to recreational shooting, while 
documented, are rare and therefore not considered a significant threat 
overall to the species. Recent Statewide estimates of occupied habitat 
further reinforce this observation by documenting population increases 
in States that allow shooting. There is no information available to 
indicate that the type of bullet used to shoot prairie dogs poses a 
substantial risk of lead poisoning to surviving prairie dogs due to 
scavenging carcasses. However, the risk to other species that may 
scavenge prairie dog carcasses should be a management consideration if 
intensive recreational shooting occurs. Since the early 1960s, occupied 
habitat has increased in every State. Throughout the United States, 
occupied habitat is estimated to have increased by over 600 percent 
from 1961 until the present time. This increase has occurred despite 
recreational shooting and impacts from other factors.
    The current status of the black-tailed prairie dog, as indicated by 
increasing trends in the species' occupied habitat since the early 
1960s, indicates that recreational shooting is not a limiting factor 
for the species. Consequently, we do not anticipate that impacts from 
recreational shooting are likely to negatively impact the status of the 
species in the foreseeable future.
    We conclude that the best scientific and commercial information 
available indicates that the black-tailed prairie dog is not now, or in 
the foreseeable future, threatened by overutilization for commercial, 
recreational, scientific, or educational purposes to the extent that 
listing under the Act as a threatened or

[[Page 63355]]

endangered species is warranted at this time. Regulations specific to 
shooting are described under Factor D.

C. Disease and Predation

    Plague is an exotic disease foreign to the evolutionary history of 
North American prairie dogs. It is caused by the bacterium Yersinia 
pestis, which fleas acquire by biting infected animals and subsequently 
transmit via a bite to other animals (Gage and Kosoy 2005, pp. 516-
517). The disease can also be transmitted through pneumonic (airborne) 
or septicemic (blood) pathways from infected to disease-free animals 
(Barnes 1993, p. 28; Ray and Collinge 2005, p. 203; Cully et al. 2006, 
p. 158; Rocke et al. 2006, p. 243; Webb et al. 2006, p. 6236). Plague 
was first observed in wild rodents in North America near San Francisco, 
California, in 1903 (Eskey and Haas 1940, p. 1), and was first 
documented in black-tailed prairie dogs in Texas in 1946 (Miles et al. 
1952, p. 41). Plague spread approximately 1,400 mi (2,250 km) eastward 
from its initial introduction in San Francisco into the species' 
habitat in approximately 40 years, but eastward expansion has since 
slowed (Adjemian et al. 2007, p. 365). Plague has only spread a few 
hundred miles in the past 50-60 years.
    Plague is maintained in nature through fleas and certain rodent 
hosts that have sufficient resistance to maintain the disease at a low 
level of transmission with little evident mortality in animals carrying 
plague (enzootic cycle). Occasionally, the disease spreads from 
enzootic hosts to more susceptible animals, resulting in a rapidly 
spreading die-off affecting a large number of animals (epizootic cycle) 
(Barnes 1993, p. 29; Biggins and Kosoy 2001, p. 909; Cully and Williams 
2001, p. 900; Gage and Kosoy 2005, pp. 506-508). The factors that cause 
a change from an enzootic to epizootic cycle are still being 
researched, but may include host density, flea density, and climatic 
conditions (Cully 1989, p. 49; Parmenter et al. 1999, p. 814; Cully and 
Williams 2001, pp. 899-903; Enscore et al. 2002, p. 186; Lomolino et 
al. 2003, pp. 118-119; Stapp et al. 2004, p. 237; Gage and Kosoy 2005, 
p. 509; Ray and Collinge 2005, p. 204; Stenseth et al. 2006, p. 13110; 
Adjemian et al. 2007, p. 372; Snall et al. 2008, p. 246).
    Black-tailed prairie dogs are very sensitive to plague, and 
mortality frequently reaches 100 percent (Barnes 1993, p. 28). Two 
patterns of die-offs are typically described for black-tailed prairie 
dogs: (1) A rapid and nearly 100 percent die-off with incomplete 
recovery, such as has occurred at the Rocky Mountain Arsenal and the 
Comanche National Grassland in Colorado (Cully and Williams 2001, pp. 
899-903); and (2) a partial die-off resulting in smaller, but stable, 
populations and smaller, more dispersed colonies, such as has occurred 
at the Cimarron National Grassland in Kansas (Cully and Williams 2001, 
pp. 899-903) and Pawnee National Grassland in Colorado (Derner et al. 
2006, p. 459).
    Several reports have suggested that the response of black-tailed 
prairie dogs to plague may vary based on population density or degree 
of colony isolation (Cully 1989, p. 49; Cully and Williams 2001, pp. 
899-903; Lomolino et al. 2003, pp. 118-119). Colony complexes with a 
history of recurring plague are typically composed of smaller colonies 
with greater intercolony distances. A frequent assumption of 
metapopulation conservation is that larger and closer populations are 
preferable to smaller and more isolated populations; however, this may 
not be the case when populations are exposed to a highly virulent 
pathogen such as plague that can be transferred from patch to patch by 
species movement (Johnson 2005, pp. 73-74).
    Table 2 illustrates die-offs and extent of recovery for several 
well-studied sites that have experienced plague epizootics (outbreak), 
although some of these sites may have also been influenced by 
poisoning. Any conclusions as to decreasing or increasing trends in 
black-tailed prairie dog populations described in Table 2 are temporal 
in nature and site-specific. Long-term, large-scale population trends 
appear to be increasing.

            Table 2. Site-specific Population Estimates of Occupied Black-tailed Prairie Dog Habitat Pre- and Post-Plague (PP = Post-Plague)
--------------------------------------------------------------------------------------------------------------------------------------------------------
              Site                  1\st\ Estimate      2\nd\ Estimate      3\rd\ Estimate      4\th\ Estimate      5\th\ Estimate      6\th\ Estimate
--------------------------------------------------------------------------------------------------------------------------------------------------------
Comanche NG, CO                   5,000 (2,023),      1,600 (647),        10,700 (4,330),     3,000 (1,214),                          ..................
                                   1995 \1\           1999 \1\ (PP).....   2005 \1\            2006 \1\ (PP)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Meadow Springs Ranch, CO          3,336 (1,351),      1,393 (564), 2007   360 (146), 2008                                             ..................
                                   2006 \2\            \2\ (PP)            \2\ (PP)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Pawnee NG, CO                     731 (296), 1998     744 (301), 1999     983 (398), 2000     3,300 (1,337),      2,398 (971), 2008   ..................
                                   \3\                 \4\                 \4\                 2005 \5\            \5\ (PP)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Pueblo Chemical Depot, CO         4,333 (1,753),      67 (27), 2000 \6\   3,423 (1,385),      2,712 (1,097),                          ..................
                                   1998 \6\            (PP)                2005 \6\            2006 \6\ (PP)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Rocky Mt. Arsenal, CO             4,574 (1,851),      247 (99), 1989 \7\  2,429 (982),        22 (8), 1995 \7\    1,646 (666),        314 (127), 2002
                                   1988 \7\            (PP)               1994 \7\..........   (PP)               2000 \7\..........   \8\ (PP)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Cimarron NG, KS                   1,716 (695),        1,287 (521),        1,688 (684),        2,639 (1,069),      3,321 (1,345),      1,337 (541), 2008
                                  1988 \3\..........  1998 \3\..........  1999 \4\..........  2001 \4\..........  2002 \9\..........   (PP) \5\
--------------------------------------------------------------------------------------------------------------------------------------------------------
CMR NWR, MT                       4,859 (1,968),      2,064 (836),        1,729 (700),                                                ..................
                                   2004 \10\          2007 \10\ (PP)....  2008 \10\ (PP)....
--------------------------------------------------------------------------------------------------------------------------------------------------------
Ft. Belknap Res., MT              24,000 (9,720),     11,000 (4,455),     13,475 (5,457),     14,230 (5,763),     12,987 (5,260),     12,989 (5,261),
                                   1990 \11\           1996 \11\ (PP)      1998 \11\           1999 \12\           2000 \12\           2002 \12\
--------------------------------------------------------------------------------------------------------------------------------------------------------
N Cheyenne Res., MT               10,720 (4,338),     378 (152), 1995     3,300 (1,335),      3,913 (1,585),      5,683 (2,299),      ..................
                                   1990 \13\           \14\ (PP)           2002 \15\           2003 \15\           2006 \13\
--------------------------------------------------------------------------------------------------------------------------------------------------------

[[Page 63356]]

 
Kiowa/Rita Blanca NG, TX, OK, NM  1,600 (647),        6,800 (2,751),      4,500 (1,821),      3,000 (1,214),                          ..................
                                  1999 \9\..........   2003 \9\            2004 \9\ (PP)       2005 \9\ (PP)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Cimarron County, OK               1,837 (744),        5,500 (2,228),      10,406 (4,214),     2,370 (960),        1,975 (800),        13,523 (5,477),
                                  1967 \16\.........   1972 \17\           1989 \18\          1991 \19\ (PP)....  1999 \20\.........   2002 \21\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Buffalo Gap NG, SD                42,600 (17,253),    13,270 (5,374),     18,105 (7,333),     ~38,000 (15,400),   28,993 (11,742),    ..................
                                   1980 \4\            1998 \3\            2002 \4\            2007 \5\            2008 \5\ (PP)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Thunder Basin NG, WY              6,301 (2,552),      18,340 (7,428),     18,239 (7,387),     15,864 (6,425),     9,000 (3,642),      3,700 (1,500),
                                   1980 \4\            1997 \4\            1998 \3\            2001 \4\ (PP)       2003 \22\ (PP)      2008 \5\ (PP)
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Augustine et al. 2008
\2\ Bachland 2008
\3\ Sidle 1999
\4\ Thompson 2002
\5\ Sidle 2009b
\6\ Young 2008
\7\ Seery 2001
\8\ Seery 2002
\9\ Cully and Johnson 2006
\10\ Dullum 2009
\11\ FaunaWest 1998
\12\ Vosburg 2002
\13\ Larson 2008
\14\ Fourstar 1998
\15\ Vosburg 2003
\16\ Tyler 1968
\17\ Lewis and Hassien 1973
\18\ Shackford et al. 1990
\19\ Shaw et al. 1993
\20\ Lomolino 1999
\21\ Luce 2002
\22\ Byer 2003

    Some studies have documented the development of antibodies in 
black-tailed prairie dogs surviving a plague epizootic. Over 50 percent 
of survivors developed antibodies at one Colorado site (Pauli 2005, pp. 
1, 71). The degree of evolved resistance, assuming little or no 
resistance initially, is not known. However, a preliminary assessment 
of natural resistance to plague found that prairie dogs collected from 
South Dakota (minimal plague), Texas (historical plague outbreaks), and 
Colorado (ongoing plague outbreaks) had differing levels of resistance. 
When challenged with the same doses of plague inoculum, nearly all 
South Dakota animals died, but 60 percent and 50 percent of animals 
from Texas and Colorado respectively survived over all doses (Rocke 
2009, p. 1). Laboratory research indicates that at low levels of 
exposure a small percentage of black-tailed prairie dogs show some 
immune response and consequently some resistance to plague, indicating 
that development of a plague vaccine may be feasible (Creekmore et al. 
2002, pp. 32, 38). Research on development of a plague vaccine has 
demonstrated significantly higher antibody levels and survival rates in 
vaccinated black-tailed prairie dogs that were challenged with the 
plague bacterium (Mencher et al. 2004, pp. 5, 8-9; Rocke et al. 2008, 
p. 930). Oral vaccination may be effective for managing plague 
epizootics in select free-ranging prairie dog populations by reducing 
mortality in exposed individuals (Mencher et al. 2004, pp. 8-9). 
However, we need to conduct field tests before using it as a management 
tool.
    Since our last evaluation of the status of the black-tailed prairie 
dog in 2004, when it was removed from the candidate list, plague has 
expanded its range into South Dakota, previously the only State where 
plague had not been documented in prairie dogs (U.S. Fish & Wildlife 
Service 2005a, p. 1). The disease reached Conata Basin in 2008, despite 
3 years of treating prairie dog burrows in portions of the affected 
area with insecticide in an effort to kill fleas and thereby limit 
plague transmission (a process referred to as ``dusting'').
    Conata Basin is one of the largest remaining black-tailed prairie 
dog complexes and is the most successful recovery site in North America 
for the endangered black-footed ferret. Approximately 10,505 ac (4,251 
ha) have been affected by plague through May 2009 in Conata Basin 
(Griebel 2009, p. 1). Within the plague zone, there are typically 
scattered individuals or small pockets of 1 to 2 ac (0.4 to 0.8 ha) 
where prairie dogs either have natural immunity or escaped exposure by 
chance (Griebel 2008, p. 4).
    Plague has also been documented on Pine Ridge and Cheyenne River 
Reservations in South Dakota (Mann-Klager 2008, pp. 1-2). Creekmore et 
al. (2002, p. 38) noted that the establishment of sylvatic plague in 
South Dakota could have a substantial impact on population dynamics of 
both the black-tailed prairie dog and the black-footed ferret in South 
Dakota. However, at this time less than 2 percent of occupied habitat 
in the State has been affected by plague and occupied habitat continues 
to increase Statewide. Occupied habitat also continues to increase in 
States that have had plague present for more than 50 years.
    Sylvatic plague remains a significant population stressor and the 
spread and effects of plague on the species could be exacerbated by 
climate change in the future. The extent to which the spread of plague 
may expand or contract in the future is not clear. Regardless of how 
plague is affected by climate change, the black-tailed prairie dog has 
proven to be

[[Page 63357]]

a resilient species. In spite of the past and current effects of plague 
and climate change and resulting impacts acting on the species, 
occupied habitat (a surrogate measure for population trends and status) 
in the United States has increased by more than 600 percent since the 
early 1960s. Although the effects of plague could be exacerbated by 
climate change in the future, the current status of the black-tailed 
prairie dog does not suggest that plague, or the combined effects of 
plague and climate change, are a limiting factors for the species in 
the foreseeable future, and we do not believe these will result in 
significant population-level impacts. The present or threatened 
curtailment of prairie dog habitat presented by climate change is 
addressed further under Factor E.
    Tularemia and monkey pox are diseases that have had impacts on 
captive black-tailed prairie dogs associated with the pet trade; 
however, we have no information to indicate that either of these 
diseases are a concern for wild prairie dogs.
    Many species prey upon the black-tailed prairie dog; however, we 
have no information to indicate that predation is a concern.
Summary of Factor C
    Plague has expanded its range to all States within the range of the 
black-tailed prairie dog in recent years and has caused local 
population declines at several sites. These declines are typically 
followed by partial or complete recovery. Development of a vaccine to 
protect prairie dog populations has begun, and resistance to plague has 
been observed in some individuals. Since the early 1960s, occupied 
habitat has increased in every State, even in those States where plague 
has been present for over 50 years. Throughout the United States, 
occupied habitat is estimated to have increased by over 600 percent 
from 1961 until the present time. This increase has occurred despite 
continued impacts from plague and other factors.
    The current status of the black-tailed prairie dog, as indicated by 
increasing trends in the species' occupied habitat since the early 
1960s, indicates that plague is not a limiting factor for the species. 
Although Sylvatic plague remains a population stressor and the spread 
and effects of plague on the species could be exacerbated by climate 
change in the long term future, the black-tailed prairie dog has proven 
to be a resilient species. In spite of the past and current effects of 
plague and climate change and resulting impacts on the species, black-
tailed prairie dog occupied habitat (a surrogate measure for population 
trends and status) in the U.S. has increased by more than 600 percent 
since the early 1960s. Although the effects of plague could be 
exacerbated by climate change in the future, the current status of the 
black-tailed prairie dog does not suggest that the combined effects of 
climate change and plague, are a limiting factor for the species in the 
foreseeable future, and we do not believe these will result in 
significant population-level impacts. Consequently, we do not 
anticipate that impacts from the disease are likely to negatively 
impact the status of the species in the foreseeable future. Therefore, 
we have no reason to suspect that plague poses a significant threat to 
the species.
    We conclude that the best scientific and commercial information 
available indicates that the black-tailed prairie dog is not now, or in 
the foreseeable future, threatened by disease or predation to the 
extent that listing under the Act as a threatened or endangered species 
is warranted at this time.

D. The Inadequacy of Existing Regulatory Mechanisms

    Traditionally, resident species that are not federally threatened 
or endangered are usually managed by States or Tribes. Federal land 
management agencies may have additional management policies on their 
lands. The three primary means by which agencies can effectively 
influence black-tailed prairie dog populations are via shooting 
regulations, poisoning regulations, and proactive management. Detailed 
information regarding existing regulatory and management measures 
affecting the species is provided below.
Arizona
    Classification - The species is classified as nongame (animals that 
are not traditionally hunted, fished, or trapped) (Voyles 2009, p. 2).
    Shooting - A hunting license is required to shoot prairie dogs. The 
hunting season for black-tailed prairie dogs has been closed since 1999 
(Voyles 2009, p. 2).
    Poisoning - Toxicants are permitted for use on prairie dogs in 
Arizona, typically in conjunction with human health related to plague 
or safety concerns; however, plague has not been identified within the 
range of the black-tailed prairie dog in Arizona since its 
reintroduction in 2008, and no poisoning has occurred (Voyles 2009, p. 
2).
    Management Plans - Arizona is a signatory to the interstate 
Conservation Assessment and Strategy (Van Pelt 1999, p. 71). The 
Statewide management plan (Van Pelt et al. 2001) for Arizona supports, 
but does not meet, the objectives described in the Multi-State Plan. 
The Statewide management plan for Arizona has not been approved. The 
Statewide comprehensive wildlife strategy recognizes the black-tailed 
prairie dog as a species of concern (Arizona Game and Fish Dept. 2006, 
pp. 443-445). However, this designation does not result in any 
protection for the species.
Colorado
    Classification - The black-tailed prairie dog is classified as 
small game (CDOW 2009, p. 2).
    Shooting - In 2006, the State removed the ban on hunting black-
tailed prairie dogs on public land (Nesler 2009, p. 5). The hunting 
season is year-round on private land and June 15 through the end of 
February on public land. A small game license is required. There is no 
bag limit (CDOW 2009, p. 2).
    Poisoning - Chemical control is jointly regulated by the Colorado 
Department of Agriculture, and the CDOW and is limited to those 
pesticides legally permitted for use on black-tailed prairie dogs. 
Prairie dogs may also be taken by use of explosive gases where 
necessary to control damage on private lands (CDOW 2009, p. 4).
    Management Plans - Colorado is not a signatory to the interstate 
Conservation Assessment and Strategy (Van Pelt 1999, p. 71). The 
Statewide management plan (CDOW 2003) for Colorado supports and meets 
all of the objectives described in the Multi-State Plan. The Statewide 
management plan for Colorado has been approved. The Statewide 
comprehensive wildlife strategy recognizes the black-tailed prairie dog 
as a species of concern (CDOW 2006, p. 98). However, this designation 
does not result in any protection for the species.
Kansas
    Classification - The Kansas Department of Wildlife and Parks 
classifies the species as wildlife (Kansas Department of Wildlife and 
Parks 2009, p. 1).
    Shooting - The hunting season is year-round on private and public 
lands. A hunting license is required for residents and nonresidents. 
There is no bag limit (Kansas Department of Wildlife and Parks 2009, p. 
2).
    Poisoning - The most recent information available to us indicates 
that a permit is required to use any poisonous gas or smoke, but is not 
required to use above ground toxicants (Mitchener 2003, p. 2). 
According to Kansas Statutes 80-1201, 1202, and

[[Page 63358]]

1203, control may be legislated at a local level. For example, several 
townships have imposed mandatory control requirements. In some cases, 
landowners are instructed to control prairie dogs on their land; if 
they fail to do so, it is done by the county at the landowner's expense 
(Kansas Legislature 2009, pp. 1-8).
    Management Plans - Kansas is a signatory to the interstate 
Conservation Assessment and Strategy (Van Pelt 1999, p. 71). The 
Statewide management plan (Kansas Department of Wildlife and Parks 
2002) for Kansas supports, but does not meet, all of the objectives 
described in the Multi-State Plan. Kansas does not meet the objective 
of maintaining at least 10 percent of total occupied area in complexes 
greater than 1,000 ac (405 ha) (Van Pelt 2009, p. 16). The Statewide 
management plan for Kansas has been approved. The Statewide 
comprehensive wildlife strategy recognizes the black-tailed prairie dog 
as a species of concern (Wasson et al. 2005, Appendix 1). However, this 
designation does not result in any protection for the species.
Montana
    Classification - The species is classified as a vertebrate pest 
under the Montana Department of Agriculture (Bamber 2009, pp. 1-2). The 
State legislature allowed the dual status of ``nongame wildlife in need 
of management'' and ``vertebrate pest'' to expire in 2007 (Bamber 2009, 
pp. 1-2). A bill to resume dual classification and management of the 
black-tailed prairie dog failed to pass in the 2009 Montana legislative 
session (Hanauska-Brown 2009, p. 2).
    Shooting - The hunting season is year-round on private and public 
lands. No hunting license is required for residents or nonresidents 
(Van Pelt 2009, p. 21). There is no bag limit.
    Poisoning - Chemical control is regulated by the Montana Department 
of Agriculture. The Department employs a vertebrate pest specialist to 
assist Federal, State, and County agencies and private landowners with 
training and certification of pesticide applicators. There is no 
funding or personnel for the Montana Department of Agriculture to 
conduct prairie dog control programs. No control is currently occurring 
on Federal or tribal lands, and the level of control on private and 
State lands has remained stable in recent years (Bamber 2009, pp. 1-2).
    Management Plans - Montana is a signatory to the interstate 
Conservation Assessment and Strategy (Van Pelt 1999, p. 71). The 
Statewide management plan (Montana Department of Fish, Wildlife and 
Parks 2002) for Montana does not support or meet the occupied area 
objective. The Statewide management plan for Montana has been approved. 
The Statewide comprehensive wildlife strategy recognizes the black-
tailed prairie dog as a species of concern (Montana Fish, Wildlife and 
Parks 2005, pp. 375-378). However, this designation does not result in 
any protection for the species.
Nebraska
    Classification - The species is classified as unprotected nongame 
(Amack and Ibach 2009, p. 2).
    Shooting - The hunting season is year-round on private and public 
lands. No hunting license is required for residents. Nonresidents must 
have a small game hunting license. There is no bag limit (Amack and 
Ibach 2009, p. 2).
    Poisoning - Chemical control is regulated by the Nebraska 
Department of Agriculture and is limited to those pesticides legally 
permitted for use on black-tailed prairie dogs. The U. S. Animal and 
Plant Health Inspection Service and landowners conduct control work 
(Amack and Ibach 2009, p. 3).
    Management Plans - Nebraska is a signatory to the interstate 
Conservation Assessment and Strategy (Van Pelt 1999, p. 71). The 
Statewide management plan (Nebraska Game and Parks Commission 2001) for 
Nebraska supports, but does not meet, all of the objectives described 
in the Multi-State Plan. Nebraska does not meet the objective of 
managing or contributing to at least one complex greater than 5,000 ac 
(2,023 ha) and does not meet the objective of maintaining distribution 
throughout at least 75 percent of the historic range in the State (Van 
Pelt 2009, p. 26). The Statewide management plan for Nebraska has not 
been approved. The Statewide comprehensive wildlife strategy does not 
recognize the black-tailed prairie dog as a species of concern 
(Schneider et al. 2005, pp. 203, 236).
New Mexico
    Classification - The species is not classified as having any status 
by the State other than that described by the Statewide comprehensive 
wildlife strategy (Van Pelt 2009, p. 28).
    Shooting - The hunting season is year-round on private and public 
lands. No hunting license is required for residents. Nonresidents must 
have a hunting license (Van Pelt 2009, p. 28). There is no bag limit.
    Poisoning - Chemical control is limited to pesticides legally 
permitted for use on black-tailed prairie dogs.
    Management Plans - New Mexico is a signatory to the interstate 
Conservation Assessment and Strategy (Van Pelt 1999, p. 71). The 
Statewide management plan (New Mexico Black-tailed Prairie Dog Working 
Group 2001) for New Mexico does not support or meet all of the 
objectives described in the Multi-State Plan. New Mexico does not 
support the objective of managing or contributing to at least one 
complex greater than 5,000 ac (2,023 ha), although it does meet that 
objective (Van Pelt 2009, p. 28). It does not meet the occupied area 
objective or the objective of maintaining distribution throughout at 
least 75 percent of the historic range in the State (Van Pelt 2009, p. 
28). The Statewide management plan for New Mexico has been approved. 
The Statewide comprehensive wildlife strategy recognizes the black-
tailed prairie dog as a species of concern (New Mexico Department of 
Game and Fish 2006, pp. 55, 577). However, this designation does not 
result in any protection for the species.
North Dakota
    Classification - The species is classified as a pest species by the 
North Dakota Department of Agriculture (McKenna 2009, p. 1).
    Shooting - The hunting season is year-round on private and public 
lands. No hunting license is required for residents. Nonresidents must 
have a nongame or furbearers license (McKenna 2009, p. 2). There is no 
bag limit.
    Poisoning - Current regulations allow landowners to poison black-
tailed prairie dogs if they are certified applicators (McKenna 2009, p. 
2).
    Management Plans - North Dakota is not a signatory to the 
interstate Conservation Assessment and Strategy (Van Pelt 1999, p. 71). 
The Statewide management plan (North Dakota Game and Fish Department 
2001) for North Dakota does not support or meet all of the objectives 
described in the Multi-State Plan. North Dakota does not support any of 
the objectives and does not meet any objectives except distribution 
over at least 75 percent of the historical range (Van Pelt 2009, p. 
24). The Statewide management plan for North Dakota has been approved. 
The Statewide comprehensive wildlife strategy recognizes the black-
tailed prairie dog as a species of concern (Hagen et al. 2005, pp. 27, 
305-307). However, this designation does not result in any protection 
for the species.
Oklahoma
    Classification - The species is classified as wildlife-nongame (Van 
Pelt 2009, p. 30).

[[Page 63359]]

    Shooting - The hunting season is year-round on private and public 
lands. Residents and nonresidents must have a valid State hunting 
license. There is no bag limit (Van Pelt 2009, p. 30).
    Poisoning - A permit from the Oklahoma Department of Wildlife 
Conservation is required. No permit will be issued in a county with 
less than 100 ac (40 ha) of black-tailed prairie dog occupied habitat 
(Van Pelt 2009, p. 30).
    Management Plans - Oklahoma is a signatory to the interstate 
Conservation Assessment and Strategy (Van Pelt 1999, p. 71). The 
Statewide management plan (Hoagland 2001) for Oklahoma supports, but 
does not meet all of the objectives described in the Multi-State Plan. 
Oklahoma does not meet the occupied area objective (Van Pelt 2009, p. 
30). The Statewide management plan for Oklahoma has not been approved. 
The Statewide comprehensive wildlife strategy recognizes the black-
tailed prairie dog as a species of concern (Oklahoma Department of 
Wildlife Conservation 2005, pp. 358, 360). However, this designation 
does not result in any protection for the species.
South Dakota
    Classification - The State of South Dakota modified the designation 
of ``species of management concern'' for the black-tailed prairie dog 
by designating it as a pest if plague is reported east of the Rocky 
Mountains, the Statewide population is greater than approximately 
145,000 ac (59,000 ha), or the species is colonizing within a 1 mi (1.6 
km) buffer around concerned landowners (South Dakota State Legislature 
2005, pp. 3-4). Currently, all of these criteria are being met; 
therefore, the species is considered a pest in South Dakota.
    Shooting - The hunting season is year-round on private lands and 
open from June 15 through February 28 on public lands, except for a 
year-round closure in Conata Basin. Residents and nonresidents must 
have a valid South Dakota hunting license. There is no bag limit (Van 
Pelt 2009, p. 34).
    Poisoning - Chemical control is limited to pesticides legally 
permitted for use on black-tailed prairie dogs.
    Management Plans -South Dakota is a signatory to the interstate 
Conservation Assessment and Strategy (Van Pelt 1999, p. 72). The 
Statewide management plan (Cooper and Gabriel 2005) for South Dakota 
supports and meets all of the objectives described in the Multi-State 
Plan (Vonk and Even 2009, pp. 3-4). South Dakota's management plan also 
notes that the state has identified its own goals and objectives, 
specific to South Dakota, and reserves the right to preserve their own 
management authority. The Statewide management plan for South Dakota 
has been approved. The Statewide comprehensive wildlife strategy does 
not recognize the black-tailed prairie dog as a species of concern 
(South Dakota Department of Game, Fish, and Parks 2006, pp. 65-69).
Texas
    Classification - The species is classified as nongame (Van Pelt 
2009, p. 38).
    Shooting - The hunting season is year-round on private and public 
lands. Residents and nonresidents must have a valid State hunting 
license. There is no bag limit for shooting. A nongame commercial 
dealer's permit is required for capture and selling of more than 25 
individuals (Van Pelt 2009, p. 38).
    Poisoning - Chemical control is limited to pesticides legally 
permitted for use on black-tailed prairie dogs.
    Management Plans - Texas is a signatory to the interstate 
Conservation Assessment and Strategy (Van Pelt 1999, p. 72). The 
Statewide management plan (Texas Black-tailed Prairie Dog Working Group 
2004) for Texas supports, but does not meet all of the objectives 
described in the Multi-State Plan. Texas does not meet the occupied 
area objective (Van Pelt 2009, p. 37). The Statewide management plan 
for Texas has been approved. The Statewide comprehensive wildlife 
strategy recognizes the black-tailed prairie dog as a species of 
concern (Texas Parks and Wildlife Department 2005, p. 744). However, 
this designation does not result in any protection for the species.
Wyoming
    Classification - The species is classified as a nongame mammal by 
the Wyoming Game and Fish Department and as a pest by the Wyoming 
Department of Agriculture. A Memorandum of Understanding exists to 
coordinate management of the species between the two Departments if 
survey results indicate that occupied habitat for the species is less 
than the Wyoming Game and Fish Department objectives (Emmerich 2009, p. 
3).
    Shooting - The hunting season is year-round on private and public 
lands. Residents and nonresidents are not required to have a State 
hunting license. There is no bag limit for shooting (Van Pelt 2009, p. 
40). Unlike most States, the Wyoming Game and Fish Commission has the 
authority to implement a shooting closure if it deems it necessary 
(Emmerich 2009, p. 3).
    Poisoning - Chemical control is limited to pesticides legally 
permitted for use on black-tailed prairie dogs.
    Management Plans - Wyoming is a signatory to the interstate 
Conservation Assessment and Strategy (Van Pelt 1999, p. 72). The 
Statewide management plan (Kruckenberg et al. 2001) for Wyoming 
supports and meets all of the objectives described in the Multi-State 
Plan. The Statewide management plan for Wyoming has not been approved. 
However, a grasslands conservation plan (Wyoming Game and Fish 
Department 2006, pp. 23-29, 94-130) addresses the species and has 
specific management objectives consistent with the Multi-State Plan 
(Emmerich 2009, pp. 3-4). The Statewide comprehensive wildlife strategy 
recognizes the black-tailed prairie dog as a species of concern 
(Wyoming Game and Fish Department 2005, pp. 10, 141-143). However, this 
designation does not result in any protection for the species.
Tribes
    There are several Indian Reservations within the range of the 
black-tailed prairie dog in Montana, New Mexico, North Dakota, and 
South Dakota. However, we are only aware of nine Tribes that have 
black-tailed prairie dog occupied habitat within their Reservations 
(Cheyenne River Sioux Indian Reservation, SD; Crow Indian Reservation, 
MT; Crow Creek Indian Reservation, SD; Fort Belknap Indian Reservation, 
MT; Lower Brule Indian Reservation, SD; Northern Cheyenne Indian 
Reservation, MT; Pine Ridge Indian Reservation, SD; Rosebud Indian 
Reservation, SD; and Standing Rock Indian Reservation in ND and SD). 
Tribes did not provide any new information. It is our understanding 
that hunting black-tailed prairie dogs on tribal lands requires a 
permit. The season is typically year-round, and there are no bag 
limits. Poisoning is prohibited or requires a permit. Tribes generally 
meet or exceed their proportional requirements for occupied habitat, as 
described in the Multi-State Plan.
Federal Agencies
    There are numerous Federal laws, acts, and policies in addition to 
the Act that encourage coordination of activities that may impact 
wildlife and promote conservation of wildlife. Some of the most 
frequently encountered that may influence black-tailed prairie dog 
management are described. The Fish and Wildlife Coordination Act (16 
U.S.C. 661 et seq.) requires consultation between the Service and other 
Federal agencies and equal consideration of

[[Page 63360]]

wildlife conservation with water resource development programs. The 
Fish and Wildlife Conservation Act (16 U.S.C. 2901 et seq.) authorizes 
financial and technical assistance to States for the development of 
conservation plans and programs for nongame fish and wildlife. The 
National Environmental Policy Act (42 U.S.C. 4321 et seq.) requires all 
Federal agencies to examine the environmental impacts of their actions, 
incorporate environmental information, and utilize public participation 
in the planning and implementation of all actions. Specific information 
for affected Federal agencies is provided as follows.
    U.S. Air Force - The most recent available information indicates 
that no recreational shooting is allowed on Ellsworth Air Force Base 
and Badlands Bombing Range in South Dakota; however, some chemical 
control has been conducted (Morgenstern 2003, pp. 3-4). Similarly, at 
Buckley Air Force Base in Colorado there is no recreational shooting, 
but some chemical control (Friese 2003, pp. 2, 4). We have no 
information on black-tailed prairie dog management policies from other 
bases.
    Department of Agriculture, U.S. Animal and Plant Health Inspection 
Service (APHIS) - APHIS, Wildlife Services (WS) does not manage any 
Federal lands. However, it supports prairie dog control programs in 
several States. In 2008, 129 projects were conducted regarding the 
control of black-tailed prairie dogs (primarily personal consultations) 
in Colorado, Nebraska, New Mexico, North Dakota, Oklahoma, Texas, and 
Wyoming (APHIS 2009, pp. 1-7). At a black-footed ferret reintroduction 
site in Kansas, the Service has an agreement with APHIS-WS to provide a 
staff person to control prairie dogs if neighboring landowners request 
control (LeValley 2009, pp. 1-2). APHIS-WS also has supported several 
research efforts in recent years regarding disease, control, non-target 
impacts that can be accessed on their website.
    U.S. Army - The most recent available information indicates that 
the U.S. Army manages approximately 8,800 ac (3,600 ha) of black-tailed 
prairie dog occupied habitat (Hoefert 2002, pp. 2-6). The majority of 
occupied habitat (approximately 7,000 ac/2,800 ha) occurs on Fort 
Carson Garrison in Colorado (Larson 2008, p. 73).
    U.S. Bureau of Indian Affairs - The U.S. Bureau of Indian Affairs' 
involvement in black-tailed prairie dog management has been principally 
through management of funding for prairie dog control programs on 
tribal lands in Montana, North Dakota, and South Dakota. The last 
large-scale chemical control effort for the species was directed by 
U.S. Bureau of Indian Affairs on the Pine Ridge/Oglala Sioux 
Reservation in South Dakota in the 1980s (Roemer and Forrest 1996, p. 
353).
    U.S. Bureau of Land Management - The most recent available 
information indicates that the U.S. Bureau of Land Management (BLM) 
manages approximately 39,000 ac (16,000 ha) of black-tailed prairie dog 
occupied habitat in Arizona, Colorado, Montana, New Mexico, North 
Dakota, South Dakota, and Wyoming (Lawton 2003, p. 14). The BLM manages 
prairie dogs to meet multiple-use resource objectives including 
production of livestock forage and prevention of prairie dog 
encroachment onto adjacent lands. The BLM generally adheres to State 
regulations regarding shooting, although some additional closures exist 
at black-footed ferret recovery sites.
    U.S. Environmental Protection Agency - The U.S. Environmental 
Protection Agency (EPA) influences regulatory mechanisms through its 
pesticide labeling programs that determine which pesticides can be 
legally used to poison prairie dogs, who can apply them, and what other 
label restrictions apply. The EPA has approved several chemicals for 
control of black-tailed prairie dogs. The impacts of poisoning by these 
chemicals are described in greater detail under ``Poisoning'' in Factor 
E below. Here, we describe the regulatory process employed by the EPA.
    The EPA approved zinc phosphide as a legal prairie dog control 
chemical in 1973 (Forrest and Luchsinger 2006, p. 124). The EPA has not 
responded to our request to provide information on the amount of area 
poisoned with zinc phosphide or the amount of chemical sold. This 
information would enable us to better monitor the extent and effects of 
poisoning with zinc phosphide on black-tailed prairie dogs.
    The EPA recently permitted the use of chlorophacinone and 
diphacinone (both anticoagulants) to poison prairie dogs. Use of these 
two chemicals to control prairie dogs constitutes new uses for these 
poisons. Since 2004, State agricultural departments have issued Special 
Local Needs permits under the Federal Insecticide, Fungicide, and 
Rodenticide Act (FIFRA, 7 U.S. C. 136 et seq.) Section 24(c) 
authorizing the use of chlorophacinone for poisoning prairie dogs in 
Colorado, Kansas, Nebraska, Oklahoma, Texas, and Wyoming and 
authorizing the use of diphacinone for poisoning prairie dogs in 
Colorado, Kansas, Nebraska, Texas, and Wyoming. In 2009, the EPA 
further broadened the potential scope of chlorophacinone by registering 
it under FIFRA section 3, which allows its use throughout the 11 States 
within the range of the black-tailed prairie dog. Prairie dogs are 
highly susceptible to both chlorophacinone and diphacinone, which is 
why the chemicals are popular as a control mechanism. Unlike zinc 
phosphide, secondary poisoning of several species is documented from 
chlorophacinone and diphacinone (Erickson and Urban 2004, pp. 48, 51; 
Lydick 2006, pp. 1-2; Klataske 2009, pp. 1-6; Service 2007, pp. 1-10).
    We have limited information regarding the number of prairie dogs 
that are killed by anticoagulants or the amount of habitat treated. We 
are concerned about the impacts to both the black-tailed prairie dog 
and the secondary poisoning of other species, such as black-footed 
ferrets, other mammals, eagles, and other raptors. Despite this 
concern, the amount of habitat occupied by the black-tailed prairie dog 
throughout the United States increased by over 600 percent from 1961 
until the present time.
    U.S. Fish and Wildlife Service - The Service manages over 500 
National Wildlife Refuges and their satellites, but only about 15 
refuges, satellites, or Waterfowl Production Areas have black-tailed 
prairie dogs. Three refuges have a majority of occupied habitat on 
Service lands (approximately 6,000 ac/2,400 ha). On Charles M. Russell 
and UL Bend National Wildlife Refuges in Montana, black-tailed prairie 
dog habitat is managed to enhance its value as a black-footed ferret 
reintroduction site. The Rocky Mountain Arsenal National Wildlife 
Refuge in Colorado is managed to support black-tailed prairie dogs and 
a diversity of wildlife. Current Service management policy allows 
managers on Service lands to:
    (1) control the species as needed for public health and safety,
    (2) translocate up to 30 percent of the population annually with 
proper coordination with State wildlife agencies, and
    (3) control the species to accommodate wildlife and habitat 
objectives after completion of a prairie dog management plan and 
evaluation by a Service review committee (Service 2005b, pp. 1-2).
    Managers of Service lands are also encouraged to work cooperatively 
with neighboring landowners and local governments through the use of 
agreements and technical and financial assistance.
    Department of Agriculture, U.S Forest Service - The U.S. Forest 
Service (USFS) reduced their restrictions on

[[Page 63361]]

poisoning by rescinding a 2000 policy letter regarding control of 
black-tailed prairie dogs and allowing expanded poisoning on their 
lands (Manning 2004, pp. 2-4). The USFS manages an estimated 57,606 ac 
(23,312 ha) of black-tailed prairie dog occupied habitat (Sidle 2009b, 
p. 3). The USFS manages prairie dogs to meet multiple-use resource 
objectives including production of livestock forage and prevention of 
prairie dog encroachment onto adjacent lands. Recreational shooting is 
typically regulated by the State and is allowed on most National 
Grasslands, although some additional closures exist at black-footed 
ferret recovery sites. In 2008, the USFS poisoned 3,679 ac (1,489 ha) 
of black-tailed prairie dog occupied habitat (Sidle 2009b, p. 3). This 
control addressed encroachment of prairie dogs onto adjacent private 
lands. Most of this (2,489 ac/1,008 ha) was on Buffalo Gap National 
Grassland. Nevertheless, lands poisoned on Buffalo Gap constitute less 
than 0.4 percent of occupied habitat in South Dakota.
    U.S. National Park Service - The U.S. National Park Service manages 
approximately 13,777 ac (5,575 ha) of black-tailed prairie dog occupied 
habitat (Van Pelt 2009, p. 71). A majority of occupied habitat (8,993 
ac/3,642 ha) occurs on Badlands National Park in South Dakota (Van Pelt 
2009, p. 71). Some poisoning with zinc phosphide and shooting by 
National Park Service rangers occurs in boundary areas for ``good 
neighbor'' purposes (Davila 2009, p. 1). The most recent National Park 
Service guidance notes that black-tailed prairie dogs are managed under 
policies for conserving native species, but that some control may be 
necessary for ``good neighbor'' and human health reasons. The use of 
anticoagulants is not approved due to impacts on non-target species 
(Davila 2009, pp. 3-4).
    Canada - The black-tailed prairie dog is designated as vulnerable 
by the Committee on the Status of Endangered Wildlife in Canada. The 
management plan for the black-tailed prairie dog in Canada notes that 
the species will be allowed to naturally fluctuate on land managed by 
the Province of Saskatchewan, but if colonies expand beyond their 2007 
boundaries, the affected land manager may implement control measures 
under authority of a permit issued by Saskatchewan Environment, with 
nonlethal control measures encouraged (Tuckwell and Everest 2009, p. 
15).
    Mexico - The most recent available information indicates that there 
is no shooting of black-tailed prairie dogs and little chemical control 
in Mexico (List 2001, p. 1). The species is listed as threatened by the 
Lista de las Especies Amerzadas, the official endangered and threatened 
species list of the Mexican government (SEMARNAP 1994).
Summary of Factor D
    The affected State and Federal agencies are engaged in black-tailed 
prairie dog management and monitoring to a much greater extent than 
they were 10 years ago, before creation of the Prairie Dog Conservation 
Team. Nevertheless, agencies continue to have conflicting policies 
regarding prairie dog management. For example, Kansas has an approved 
management plan that supports all of the objectives described in the 
Multi-State Plan, and their Statewide comprehensive wildlife strategy 
recognizes the black-tailed prairie dog as a species of concern. 
However, the State's only complex greater than 5,000 ac (2,023 ha), 
which satisfies an objective from the Multi-State Plan and is also a 
black-footed ferret recovery site, potentially could be reduced or 
eliminated by the Logan County Commission, which under state law has 
authority to control prairie dogs, against the landowners' wishes and 
at the landowners' expense (Haverfield and Haverfield 2009, pp. 1-6).
    In some cases, Statewide occupied habitat is increasing in spite 
of, rather than because of, agency actions, which indicates that the 
species has been persistent despite state management contradictions. 
However, there is no evident correlation between the magnitude of 
increase in the species' population in a particular State and the 
extent to which a State is engaged in proactive management. Since the 
early 1960s, occupied habitat has increased in every State. Throughout 
the United States, occupied habitat is estimated to have increased by 
over 600 percent from 1961 until the present time. This increase has 
occurred despite regulatory mechanisms that favor control of the 
species and other factors.
    The current status of the black-tailed prairie dog, as indicated by 
increasing trends in the species' occupied habitat since the early 
1960s, indicates that inadequate regulatory mechanisms are not a 
limiting factor for the species. Consequently, we do not anticipate 
that impacts from inadequate regulatory mechanisms are likely to 
negatively impact the status of the species in the foreseeable future.
    We conclude that the best scientific and commercial information 
available indicates that the black-tailed prairie dog is not now, or in 
the foreseeable future, threatened by inadequate regulatory mechanisms 
to the extent that listing under the Act as an endangered or threatened 
species is warranted at this time.

E. Other Natural or Manmade Factors Affecting Its Continued Existence

    Under this factor we evaluate poisoning, drought, and climate 
change.
Poisoning
    Early poisoning of prairie dogs typically was conducted with 
strychnine and carbon bisulphide, with Compound-1080 becoming popular 
after World War II (Forrest and Luchsinger 2006, p. 122). Early 
poisoning efforts led to extirpation of the black-tailed prairie dog in 
Arizona by approximately 1940 (Arizona Game and Fish Dept. 1988, p. 
26). Both Compound-1080 and strychnine can cause secondary poisoning of 
non-target predators and scavengers that prey on poisoned prairie dogs. 
Concern over secondary poisoning from strychnine and Compound-1080 led 
to a report by Cain et al. (1972, p. 6). The Council on Environmental 
Quality and the Department of the Interior requested this report and 
instructed the authors to evaluate existing animal control programs and 
provide recommendations. One of the recommendations was to remove from 
registration all toxicants used for predator control and those 
toxicants used for rodent control that resulted in secondary poisoning 
of non-target animals, because such methods were likely to be inhumane 
(Cain et al. 1972, pp. 5-6).
    These recommendations led to Executive Order 11643, which in 1972 
banned the use of toxicants that might cause secondary poisoning on 
public lands or via Federal programs. In 1982, this order was revoked 
by Executive Order 12342. However, poisoning prairie dogs with 
strychnine and Compound-1080 did not resume. The total area throughout 
the range of the species that was poisoned from 1915-1965 was likely 
more than 37 million ac (15 million ha) (Forrest and Luchsinger 2006, 
p. 120). The broad-scale, government sponsored poisoning that occurred 
during the first half of the twentieth century likely contributed to 
the species reaching a low point of 364,000 ac (147,000 ha) of occupied 
habitat in the early 1960s. Since then, poisoning has generally 
occurred on a more local scale and been conducted by individual 
landowners.
    Since 1973, the two most commonly used toxicants have been zinc 
phosphide (administered via oats or other grain) and fumigants 
(administered via insertion into

[[Page 63362]]

burrows) (Forrest and Luchsinger 2006, p. 124). Both toxicants can pose 
a risk to non-target wildlife from primary exposure. In recent years 
anticoagulants such as chlorophacinone (trade name Rozol) and 
diphacinone (trade name Kaput) have become popular, as described under 
Factor D. In addition to risks of primary toxicity to non-target 
wildlife, these products pose a risk of secondary poisoning to non-
target wildlife that is not a concern with zinc phosphide. These risks 
from secondary poisoning are similar to those raised 37 years ago by 
Cain et al. (1972, p. 6). Secondary poisoning has been documented in 
badgers (Lydick 2006, pp. 1-2; Klataske 2009, pp. 1-6) and a bald eagle 
(Service 2007, pp. 1-10) as a result of legal application of 
chlorophacinone for control of black-tailed prairie dogs.
    Anticoagulants such as chlorophacinone and diphacinone cause a more 
prolonged period of distress for the black-tailed prairie dog prior to 
mortality than zinc phosphide. Anticoagulants act as blood thinners, 
with poisoned animals loosing blood through various orifices, including 
eventually the skin membranes, over a period of weeks (Erickson and 
Urban 2004, p. 3). For example, two weeks after an illegal application 
of chlorophacinone on 160 ac (65 ha) in South Dakota in 2005, we found 
dying prairie dogs. In contrast, zinc phosphide causes mortality in a 
matter of hours. We do not have any information on the amount of 
anticoagulants sold for prairie dog control or the amount of land 
treated.
    The most complete information that we have regarding the amount of 
black-tailed prairie dog habitat poisoned or the amount of poison sold 
is from the South Dakota Department of Agriculture, which jointly 
manages prairie dog control with the South Dakota Department of Game, 
Fish and Parks. South Dakota is the only State that has been permitted 
by EPA to manufacture and sell zinc phosphide. Sales from the South 
Dakota bait station are largely limited to South Dakota, Wyoming, and 
Nebraska. The available information indicates that sales from the South 
Dakota bait station fluctuate, but in general have increased since we 
removed the black-tailed prairie dog from the candidate list in 2004 
(Cerovski 2004, p. 101; Kempema 2007, p. 8). Figure 1 includes the 
total sales of zinc phosphide bait by the South Dakota bait station in 
the 4 years prior to candidate removal and the 4 years following 
candidate removal.
    Figure 1. Sales of Zinc Phosphide Bait Prior (Fridley 2003, p. 2) 
and Subsequent to (Josten 2009, p. 3) our 2004 Removal of the Black-
tailed Prairie Dog from the Federal Candidate List. Total sales for 
2009 not yet tabulated.
[GRAPHIC] [TIFF OMITTED] TP03DE09.079

    Zinc phosphide sales do not necessarily reflect effective 
application. For example, individuals may stockpile poison, re-treat 
previously poisoned land, or apply it at rates different than the 
recommended rate of 1/3 pound per acre (Hygnstrom and Virchow 1994, p. 
B89). Additionally, the South Dakota bait station is only one of 
several suppliers of prairie dog poison. However, to provide some 
perspective, if all of the zinc phosphide bait were applied at the 
recommended rate of 1/3 pound per acre, enough poison has been sold by 
this one facility since removal of the black-tailed prairie dog from 
the candidate list in 2004 to theoretically poison over 3.5 million ac 
(1.4 million ha). This equates to more than all estimated occupied 
habitat in the United States with enough remaining to poison an 
additional one million ac (400,000 ha).
    Some additional information regarding the extent of poisoning is 
available for other States within the range of the black-tailed prairie 
dog. In Kansas, an estimated 40,000 ac (16,200 ha) of private land have 
been poisoned recently (Van Pelt 2009, p. 16). There has been no 
indication of an increase in poisoning in Montana in recent years 
(Bamber 2009, p. 2). The most recent survey in North Dakota noted that 
approximately 43 percent of colonies on private land (approximately 
9,700 ac/3,900 ha) had some indication of poisoning, although total 
occupied habitat increased (Knowles 2007, p. 2). An estimated 900 ac 
(400 ha) have been poisoned recently in Oklahoma (Van Pelt 2009, p. 
30). The Texas Wildlife

[[Page 63363]]

Damage Management Service estimated 3,500 ac (1,420 ha) were poisoned 
in 2008 (Van Pelt 2009, p. 38). As described under Factor D, the USFS 
estimated 3,679 ac (1,490 ha) were poisoned on their lands in 2008; the 
majority was 2,489 ac (1,008 ha) in Buffalo Gap National Grassland, 
South Dakota, and 670 ac (271 ha) in Pawnee National Grassland, 
Colorado (Sidle 2009b, p. 3). No other recent estimates regarding 
poisoning were available.
    If we total poison estimates for 2008 from the South Dakota Bait 
Station, Kansas, North Dakota, Oklahoma, Texas, and Pawnee National 
Grasslands, the amount of black-tailed prairie dog occupied habitat 
poisoned in 2008 was approximately 801,000 ac (324,000 ha), or 33 
percent of estimated range wide occupied habitat. This figure does not 
include estimates for Montana or New Mexico, and only partial estimates 
are available for Colorado, Nebraska, and Wyoming.
    In a review of available research, Andelt (2006, p. 135) concluded 
that colony size increases by about 30 percent annually for several 
consecutive years following poisoning; after intense but not total 
elimination, colony size can initially increase by as much as 71 
percent annually. Colonies usually require 3 to 5 years to attain pre-
treatment size. The author further notes that complete eradication with 
100 percent mortality is ``formidably elusive.'' Earlier, government 
sponsored poisoning efforts such as those that led to the eradication 
of the black-tailed prairie dog in Arizona were likely more effective 
due to a synchronized effort by the Federal government over a large 
landscape. In recent years poisoning has typically been conducted over 
a smaller landscape such as the property of a single landowner. Despite 
the long-term and widespread poisoning of the black-tailed prairie dog, 
increasing population trends both range wide and Statewide indicate 
that localized poisoning is not adversely impacting the species' status 
and long-term conservation.
    The current status of the black-tailed prairie dog, as indicated by 
increasing trends in the species' occupied habitat since the early 
1960s, indicates that poisoning is not a threat to the species. There 
is no evidence that poisoning poses a significant threat to the species 
now or into the future.
Drought
    Drought is a natural and cyclical occurrence within the range of 
the black-tailed prairie dog to which the animal has adapted (Forrest 
2005, p. 528). In at least some instances, occupied habitat tends to 
increase during periods of drought and densities decrease, because 
animals spread out in search of food (Young 2008, p. 5). However, we 
are aware of no information that quantifies the effect of drought, 
singly or in conjunction with other threats, on the species range wide.
    The current status of the black-tailed prairie dog, as indicated by 
increasing trends in the species' occupied habitat since the early 
1960s, suggests that drought is not a limiting factor for the species. 
Therefore, we have no reason to suspect this poses a significant threat 
to the species.
Climate Change
    No information on the direct relationship between climate change 
and black-tailed prairie dog population trends is available. However, 
climate change could potentially impact the species. According to the 
Intergovernmental Panel on Climate Change (IPCC 2007, p. 6), ``warming 
of the climate system is unequivocal, as is now evident from 
observations of increases in global average air and ocean temperatures, 
widespread melting of snow and ice, and rising global average sea 
level.'' Average Northern Hemisphere temperatures during the second 
half of the 20\th\ century were very likely higher than during any 
other 50-year period in the last 500 years and likely the highest in at 
least the past 1,300 years (IPCC 2007, p. 6). It is very likely that 
over the past 50 years cold days, cold nights, and frosts have become 
less frequent over most land areas, and hot days and hot nights have 
become more frequent (IPCC 2007, p. 6). It is likely that heat waves 
have become more frequent over most land areas, and the frequency of 
heavy precipitation events has increased over most areas (IPCC 2007, p. 
6).
    Changes in the global climate system during the 21\st\ century are 
likely to be larger than those observed during the 20\th\ century (IPCC 
2007, p. 19). For the next 2 decades, a warming of about 0.2 [deg]C 
(0.4 [deg]F) per decade is projected (IPCC 2007, p. 19). Afterward, 
temperature projections increasingly depend on specific emission 
scenarios (IPCC 2007, p. 19). Various emissions scenarios suggest that 
by the end of the 21\st\ century, average global temperatures are 
expected to increase 0.6-4.0 [deg]C (1.1-7.2 [deg]F), with the greatest 
warming expected over land (IPCC 2007, p. 20).
    The IPCC (2007, pp. 22, 27) report outlines several scenarios that 
are virtually certain or very likely to occur in the 21\st\ century 
including:
    (1) over most land, there will be warmer and fewer cold days and 
nights, and warmer and more frequent hot days and nights;
    (2) areas affected by drought will increase; and
    (3) the frequency of warm spells and heat waves over most land 
areas will likely increase.
    The IPCC predicts that the resiliency of many ecosystems is likely 
to be exceeded this century by an unprecedented combination of climate 
change associated disturbances (e.g., flooding, drought, wildfire, and 
insects), and other global drivers. With medium confidence, IPCC 
predicts that approximately 20 to 30 percent of plant and animal 
species assessed so far are likely to be at an increased risk of 
extinction if increases in global average temperature exceed 1.5 - 2.5 
[deg]C (3 - 5 [deg]F).
    The black-tailed prairie dog, along with its habitat, will likely 
be affected in some manner by climate change. A shift in the species' 
geographic range may occur due to an increase in temperature and 
drought, although climate change would likely not pose as great a risk 
to prairie dog habitat as it would to species in polar, coastal, or 
montane ecosystems. Additionally, a strong relationship between plague 
outbreaks and climatic variables has been established (Parmenter et al. 
1999, p. 814; Enscore et al. 2002, p. 186; Stapp et al. 2004, p. 237; 
Gage and Kosoy 2005, p. 509; Ray and Collinge 2005, p. 204; Stenseth et 
al. 2006, p. 13110; Adjemian et al. 2007, p. 372; Snall et al. 2008, p. 
246). The key climatic variables influencing plague appear to be 
maximum daily summer temperature (plague is enhanced by cooler summer 
temperatures) and late winter precipitation (plague is enhanced by 
increased precipitation). Modeling efforts indicate that shifts in 
plague distribution may be a result of shifts of pathogen, vector, or 
host distribution due to climate change scenarios (Nakazawa et al. 
2007, p. 537). The distribution of plague may expand north and east 
(Nakazawa et al. 2007, p. 537). The recent expansion of plague into 
South Dakota supports this. However, variables associated with climate 
change and increased plague activity conflict. Plague is enhanced by 
cooler summer temperatures and by increased precipitation. 
Consequently, the extent to which plague may shift due to climate 
change versus expand or contract is supposition. Although the black-
tailed prairie dog will likely be affected by climate change, it is not 
apparent that a net loss in occupied habitat or a significant impact to 
the status of the species will result. The species is adaptable to a 
wide array of

[[Page 63364]]

climes, as evidenced by a geographic range that includes 11 States, 
Canada, and Mexico. Unlike vulnerable species in polar, coastal, and 
montane ecosystems, a shift in range could be possible.
    The current status of the black-tailed prairie dog, as indicated by 
increasing trends in the species' occupied habitat since the early 
1960s, indicates that climate change is not a threat to the species.
Summary of Factor E
    Poisoning has impacted black-tailed prairie dogs from the early 
1900s until the present time. Efforts to obtain more detailed 
information regarding the extent of poisoning, as well as efforts to 
interpret the additional recent impacts of anticoagulants, have been 
unsuccessful. Drought is a natural phenomenon throughout the range of 
the black-tailed prairie dog to which we believe the species has 
adapted. Continued climate change will likely cause shifts in the 
species' range, as well as changes in occurrence of plague. Additional 
information, particularly regarding impacts from poisoning and climate 
change, would improve our understanding of the effects on the species.
    The current status of the black-tailed prairie dog, as indicated by 
increasing trends in the species' occupied habitat since the early 
1960s, shows that poisoning, drought, climate change, or other factors 
are not threats to the species. Consequently, we do not anticipate that 
impacts from these stressors are likely to negatively impact the status 
of the species in the foreseeable future.
    We conclude that the best scientific and commercial information 
available indicates that the black-tailed prairie dog is not now, or in 
the foreseeable future, threatened by poisoning, drought, or climate 
change to the extent that listing under the Act as an endangered or 
threatened species is warranted at this time.

Finding

    As required by the Act, we considered the five factors in assessing 
whether the black-tailed prairie dog is threatened or endangered 
throughout all or a significant portion of its range. We have carefully 
examined the best scientific and commercial information available 
regarding the status and the past, present, and future threats faced by 
the black-tailed prairie dog. We reviewed information provided by the 
petitioners, information in our files, other available published and 
unpublished information, and information provided by other interested 
parties during the status review. We also consulted with Federal and 
State land managers. On the basis of the best scientific and commercial 
information available, we find that the magnitude and imminence of 
threats do not indicate that the black-tailed prairie dog is in danger 
of extinction (endangered), or likely to become endangered within the 
foreseeable future (threatened), throughout its entire range.
    There have been several impacts to the black-tailed prairie dog, in 
particular habitat loss due to conversion to cropland, sylvatic plague, 
and poisoning. Sylvatic plague and poisoning remain significant 
population stressors and are exacerbated by conflicting Federal and 
state management policies. Additionally, climate change may potentially 
impact the species in future decades. The effects of plague could be 
exacerbated by climate change in the future. However, the current 
status of the black-tailed prairie dog does not suggest that plague, or 
the combined effects of plague and climate change, are limiting factors 
for the species in the foreseeable future, and we do not believe these 
will result in significant population-level impacts. In spite of these 
stressors and resulting impacts on the species, occupied habitat (a 
surrogate measure for population trends and status) in the United 
States has increased by more than 600 percent since the early 1960s. 
The species has proven to be quite resilient and is not expected to be 
significantly affected by these stressors in the future.
    Improved management and continued research regarding plague and 
climate change could further improve the status of the black-tailed 
prairie dog. Continuing research will help increase our understanding 
of how plague, climate change, and the combined effects of these 
stressors will affect the species in the future. This will allow for 
informed management decisions related to these stressors that could 
further improve the status of the species. It could also improve the 
status of the many species that depend upon the prairie dog as a food 
source or upon prairie dog burrows for shelter. The smaller, more 
scattered prairie dog complexes that are typical today cannot support 
the diversity of wildlife that historically depended upon the prairie 
dog. For example, the black-footed ferret requires large, healthy 
prairie dog complexes for its survival.
    Our review of the information pertaining to the five factors does 
not support the assertion that there are threats of sufficient 
imminence, intensity, or magnitude to cause substantial losses of 
population distribution or viability of the black-tailed prairie dog. 
Therefore, we do not find that the black-tailed prairie dog is in 
danger of extinction (endangered), nor is it likely to become 
endangered within the foreseeable future (threatened) throughout its 
entire range. Therefore, listing the species as threatened or 
endangered under the Act is not warranted at this time.

Distinct Vertebrate Population Segments and Significant Portion of the 
Range

    After assessing whether the species is threatened or endangered 
throughout its range, we next consider whether a distinct vertebrate 
population segment (DPS) exists or whether any significant portion of 
the black-tailed prairie dog's range meets the definition of endangered 
or is likely to become endangered in the foreseeable future 
(threatened).

Distinct Vertebrate Population Segments

    To interpret and implement the distinct vertebrate population 
segment (DPS) provisions of the Act, the Service and the National 
Oceanic and Atmospheric Administration published the Policy Regarding 
the Recognition of Distinct Vertebrate Population Segments Under the 
Endangered Species Act in the Federal Register on February 7, 1996 (61 
FR 4722). Under the DPS Policy, three elements are considered in the 
decision regarding the establishment and classification of a population 
of a vertebrate species as a possible DPS:
    (1) The discreteness of a population in relation to the remainder 
of the species to which it belongs;
    (2) the significance of the population segment to the species to 
which it belongs; and
    (3) the population segment's conservation status in relation to the 
Act's standards for listing, delisting, or reclassification.
    Both discreteness and significance are required for a species 
population to meet our criteria for classification as a DPS. If any 
portion of a species population is considered a valid DPS, we may list, 
delist, or reclassify that DPS under the Act. We address these elements 
with respect to the black-tailed prairie dog.

Discreteness

    Under the DPS policy, a population segment of a vertebrate species 
may be considered discrete if it satisfies either one of the following 
conditions.

[[Page 63365]]

     (1) It is markedly separated from other populations of the same 
taxon as a consequence of physical, physiological, ecological, or 
behavioral factors. Quantitative measures of genetic or morphological 
discontinuity may provide evidence of this separation.
     (2) It is delimited by international governmental boundaries 
within which differences in control of exploitation, management of 
habitat, conservation status, or regulatory mechanisms exist that are 
significant in light of section 4(a)(1)(D) of the Act.
    We do not consider any population segment of black-tailed prairie 
dog to be markedly separated from other populations of the same taxon 
as a consequence of physical, physiological, ecological, or behavioral 
factors. As a colonial species, black-tailed prairie dogs are naturally 
distributed across the landscape in a discontinuous fashion. Black-
tailed prairie dog occupied habitat exists in a constantly shifting 
mosaic throughout an estimated 283 million ac (115 million ha) of 
suitable habitat that occurs across a range of approximately 440 
million ac (178 million ha). Because this discontinuous distribution is 
the ``baseline'' condition for the species, for us to consider any 
geographic discontinuity as being evidence of marked separation (i.e., 
discreteness) under the DPS policy, we would need the best available 
information to indicate that the amount of discontinuity is over and 
above what is considered to be normal for the species.
    We do not have detailed mapping of occupied habitat throughout the 
range of the species. We recognize the likely occurrence of some small, 
isolated black-tailed prairie dog colonies, but have very limited 
information available that identifies their locations. Therefore, we 
looked for other measures of discontinuity, such as measures of genetic 
or morphological differences as guided by the DPS policy, to determine 
whether any populations showed evidence of marked separation. There is 
minimal information available to us to indicate that any population 
segments express any genetic or morphological discontinuity due to 
separation from other prairie dog populations. We are aware of one 
study that found measurable genetic divergence in certain populations 
in Texas (Biggs 2007, p. 51). However, other studies have concluded 
that genetic differences are often as great among individuals from 
local populations as those from vastly different parts of their range 
(Chesser 1983, p. 329; Trudeau et al. 2004, p. 205). Therefore, we do 
not believe that genetic or morphological discontinuity provides 
evidence of discrete prairie dog populations.
    The black-tailed prairie dog spans international boundaries between 
the United States, Canada, and Mexico, with approximately 98 percent of 
occupied habitat occurring in the United States. However, there are no 
substantial differences in exploitation, habitat management, or 
regulatory mechanisms between the three countries. Additionally, the 
relative distribution of prairie dogs between the three countries has 
remained constant in recent years. Therefore, we do not believe that 
international boundaries provide evidence of discrete prairie dog 
populations.
    We determine, based on a review of the best available information, 
that no black-tailed prairie dog population segments meet the 
discreteness conditions of the 1996 DPS policy. Therefore, no black-
tailed prairie dog population segment qualifies as a DPS under our 
policy and is not a listable entity under the Act. The DPS policy is 
clear that significance is analyzed only when a population segment has 
been identified as discrete. Because no discrete populations of black-
tailed prairie dogs exist, we did not further analyze whether any 
populations meet the criteria in the DPS policy for significance.

Significant Portion of the Range (SPR)

    Having determined that the black-tailed prairie dog does not meet 
the definition of a threatened or endangered species range wide or in a 
DPS, we must next consider whether there are any significant portions 
of the range where the black-tailed prairie dog is in danger of 
extinction or is likely to become endangered in the foreseeable future.
    On March 16, 2007, a formal opinion was issued by the Office of the 
Solicitor of the Department of the Interior, ``The meaning of `In 
Danger of Extinction Throughout All or a Significant Portion of Its 
Range''' (USDI 2007c). We have summarized our interpretation of that 
opinion and the underlying statutory language below. A portion of a 
species' range is significant if it is part of the current range of the 
species and it contributes substantially to the representation, 
resiliency, or redundancy of the species. The contribution must be at a 
level such that its loss would result in a decrease in the ability to 
conserve the species.
    In determining whether a species is threatened or endangered in a 
significant portion of its range, we first identify any portions of the 
range of the species that warrant further consideration. The range of a 
species can theoretically be divided into portions an infinite number 
of ways. However, there is no purpose to analyzing portions of the 
range that are not reasonably likely to be significant and threatened 
or endangered. To identify only those portions that warrant further 
consideration, we determine whether there is substantial information 
indicating that: (1) the portions may be significant, and (2) the 
species may be in danger of extinction there or likely to become so 
within the foreseeable future. In practice, a key part of this analysis 
is whether the threats are geographically concentrated in some way. If 
the threats to the species are essentially uniform throughout its 
range, no portion is likely to warrant further consideration. Moreover, 
if any concentration of threats applies only to portions of the 
species' range that are not significant, such portions will not warrant 
further consideration.
    If we identify portions that warrant further consideration, we then 
determine whether the species is threatened or endangered in these 
portions of its range. Depending on the biology of the species, its 
range, and the threats it faces, the Service may address either the 
significance question or the status question first. Thus, if the 
Service considers significance first and determines that a portion of 
the range is not significant, the Service need not determine whether 
the species is threatened or endangered there. Likewise, if the Service 
considers status first and determines that the species is not 
threatened or endangered in a portion of its range, the Service need 
not determine if that portion is significant. However, if the Service 
determines that both a portion of the range of a species is significant 
and the species is threatened or endangered there, the Service will 
specify that portion of the range as threatened or endangered under 
section 4(c)(1) of the Act.
    The terms ``resiliency,'' ``redundancy,'' and ``representation'' 
are intended to be indicators of the conservation value of portions of 
the range. Resiliency of a species allows the species to recover from 
periodic disturbance. A species will likely be more resilient if large 
populations exist in high-quality habitat that is distributed 
throughout the range of the species in such a way as to capture the 
environmental variability found within the range of the species. A 
portion of the range of a species may make a meaningful contribution to 
the resiliency of the species if the area is relatively large and 
contains particularly high-quality habitat, or if its location or 
characteristics make it less susceptible

[[Page 63366]]

to certain threats than other portions of the range. When evaluating 
whether or how a portion of the range contributes to resiliency of the 
species, we evaluate the historical value of the portion and how 
frequently the portion is used by the species, if possible. In 
addition, the portion may contribute to resiliency for other reasons--
for instance, it may contain an important concentration of certain 
types of habitat that are necessary for the species to carry out its 
life-history functions, such as breeding, feeding, migration, 
dispersal, or wintering.
    Redundancy of populations may be needed to provide a margin of 
safety for the species to withstand catastrophic events. This does not 
mean that any portion that provides redundancy is necessarily a 
significant portion of the range of a species. The idea is to conserve 
enough areas of the range such that random perturbations in the system 
act on only a few populations. Therefore, each area must be examined 
based on whether that area provides an increment of redundancy that is 
important to the conservation of the species.
    Adequate representation ensures that the species' adaptive 
capabilities are conserved. Specifically, the portion should be 
evaluated to see how it contributes to the genetic diversity of the 
species. The loss of genetically based diversity may substantially 
reduce the ability of the species to respond and adapt to future 
environmental changes. A peripheral population may contribute 
meaningfully to representation if there is evidence that it provides 
genetic diversity due to its location on the margin of the species' 
habitat requirements.
SPR Evaluation for black-tailed prairie dog
    We evaluated the black-tailed prairie dog's current range in the 
context of the primary stressors affecting the species (plague, 
inadequate regulatory mechanisms, and poisoning) to determine if there 
is any apparent geographic concentration of these stressors. If effects 
to the species from all of these stressors are not disproportionate in 
any portion of the species' range, no portion is likely to warrant 
further consideration; and a determination of significance based upon 
resiliency, redundancy, or representation is not necessary.
    Plague - We regard sylvatic plague as the most substantial impact 
on the black-tailed prairie dog at the present. However, with the 
spread of plague into South Dakota, the disease now is present in 
portions of every State within the species' range, and the effects of 
plague are presumably no longer geographically concentrated in the 
western portion of the range. The current status of the black-tailed 
prairie dog, as indicated by increasing trends in the species' occupied 
habitat in every State, since the early 1960s, indicates that plague is 
not a limiting factor for the species in any State. These increasing 
trends are evident even in States with a long history of plague. Plague 
does not appear to result in disproportionate impacts to the black-
tailed prairie dog in any portion of its range. Therefore, a 
determination of significance based upon resiliency, redundancy, or 
representation is not necessary.
    Inadequate regulatory mechanisms - We evaluated the differences in 
management between States. All States within the historical range of 
the black-tailed prairie dog demonstrate both positive and negative 
management practices with regard to the species. Some States are more 
engaged than others; however, all have had stable to increasing black-
tailed prairie dog populations since 1961. Additionally, there is no 
evident correlation between the status of the species' population in a 
particular State and the extent to which a State is engaged in 
proactive management. Differences in management and the adequacy of 
regulatory mechanisms do not appear to result in disproportionate 
impacts to the black-tailed prairie dog in any portion of its range. 
Therefore, a determination of significance based upon resiliency, 
redundancy, or representation is not necessary.
    Poisoning - The most complete information with regard to the extent 
of poisoning is probably available for Arizona, South Dakota, Kansas, 
North Dakota, Oklahoma, and Texas. Only partial estimates are available 
for Colorado, Nebraska, and Wyoming. Little or no information is 
available for Montana and New Mexico. However, black-tailed prairie dog 
populations have been stable to increasing in all States. Some of the 
most intensive poisoning we are aware of has occurred in South Dakota, 
which is also the State with the largest percentage increase in the 
species' population. Poisoning does not appear to result in 
disproportionate impacts to the black-tailed prairie dog in any portion 
of its range. Therefore, a determination of significance based upon 
resiliency, redundancy, or representation is not necessary.
    We do not find that the black-tailed prairie dog is in danger of 
extinction now, nor is it likely to become endangered within the 
foreseeable future throughout all or a significant portion of its 
range. Therefore, listing the black-tailed prairie dog as threatened or 
endangered under the Act is not warranted at this time.
    We request that you submit any new information concerning the 
status of, or threats to, this species to our South Dakota Ecological 
Services Office (see ADDRESSES section) whenever it becomes available. 
New information will help us monitor this species and encourage its 
conservation. If an emergency situation develops for this species or 
any other species, we will act to provide immediate protection.

References Cited

    A complete list of all cited references is available on the 
Internet at http://www.regulations.gov and on request from the South 
Dakota Ecological Services Office (see ADDRESSES section).

Author

    The primary authors of this document are the staff members of the 
U.S. Fish and Wildlife Service, South Dakota Ecological Services Office 
(see ADDRESSES).

Authority

    The authority for this action is the Endangered Species Act of 
1973, as amended (16 U.S.C. 1531 et seq.).

    Dated: November 18, 2009.
Sam D. Hamilton,
Director, U.S. Fish and Wildlife Service.
[FR Doc. E9-28852 Filed 12-2-09; 8:45 am]
BILLING CODE 4310-55-S