[Federal Register Volume 86, Number 8 (Wednesday, January 13, 2021)]
[Rules and Regulations]
[Pages 2564-2581]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2020-28192]


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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[Docket No. FWS-R4-ES-2018-0082; FF09E22000 FXES11130900000 201]
RIN 1018-BC11


Endangered and Threatened Wildlife and Plants; Removal of the 
Interior Least Tern From the Federal List of Endangered and Threatened 
Wildlife

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Final rule.

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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), are removing 
the inland population of the least tern (Interior least tern) (Sterna 
(now Sternula) antillarum), from the Federal List of Endangered and 
Threatened Wildlife due to recovery. This determination is based on a 
thorough review of the best available scientific and commercial data, 
which indicates that the Interior least tern has recovered and the 
threats to the Interior least tern have been eliminated or reduced to 
the point that the species no longer meets the definition of an 
endangered species or threatened species under the Endangered Species 
Act of 1973, as amended (Act). Accordingly, the prohibitions and 
protections provided by the Act will no longer apply to the Interior 
least tern.

DATES: This rule is effective February 12, 2021.

ADDRESSES: The proposed and final rules, supporting documents, and the 
comments received on the proposed rule are available on the internet at 
http://www.regulations.gov under Docket No. FWS-R4-ES-2018-0082, at 
https://www.fws.gov/mississippiES/, or at https://ecos.fws.gov.

FOR FURTHER INFORMATION CONTACT: Stephen Ricks, Field Supervisor, U.S. 
Fish and Wildlife Service, Mississippi Ecological Services Field 
Office, 6578 Dogwood View Parkway, Jackson, MS 39213; telephone (601) 
321-1122. Individuals who use a telecommunications device for the deaf 
(TDD), may call the Federal Relay Service at (800) 877-8339.

SUPPLEMENTARY INFORMATION: 

Executive Summary

    Why we need to publish a rule. Under the Act, a species may be 
removed from the Federal List of Endangered and Threatened Wildlife 
(List) if it is determined that the species has recovered and no longer 
meets the definition of an endangered or threatened species. Removing a 
species from the List can only be completed by issuing a rule.
    What this document does. This rule removes the Interior least tern 
(Sterna (now Sternula) antillarum) from the List in title 50 of the 
Code of Federal Regulations (50 CFR 17.11(h)) based on its recovery.
    The basis for our action. Under the Act, we determine that a 
species is an endangered species or a threatened species based on any 
of five factors: (A) The present or threatened destruction, 
modification, or curtailment of its habitat or range; (B) 
overutilization for commercial, recreational, scientific, or 
educational purposes; (C) disease or predation; (D) the inadequacy of 
existing regulatory mechanisms; or (E) other natural or manmade factors 
affecting its continued existence. We must consider the same factors 
when removing a species from the List (i.e., ``delisting'' a species). 
We may delist a species if we find, after conducting a status review 
based on the best scientific and commercial data available, that: (1) 
The species is extinct; (2) the species does not meet the definition of 
an endangered species or a threatened species (e.g., because it has 
recovered); or (3) the listed entity does not meet the statutory 
definition of a species (50 CFR 424.11(e)). We have determined that the 
Interior least tern is not in danger of extinction now nor likely to 
become so in the foreseeable future based on a comprehensive review of 
its status and listing factors. Accordingly, we have determined that 
the species may be delisted based on recovery as a result of: (1) A 
range extension; (2) an increase in abundance and number of breeding 
sites; (3) resiliency to existing and potential threats; (4) the 
implementation of beneficial management practices; and (5) changes in 
existing regulatory mechanisms that are more protective of migratory 
bird habitats.
    Peer review and public comment. We evaluated the species' needs, 
current conditions, and future conditions to prepare our October 24, 
2019, proposed rule (84 FR 56977). We sought and evaluated comments 
from independent specialists to ensure that our determination is based 
on scientifically sound data, assumptions, and analyses. We also 
invited these peer reviewers to comment on the draft post-delisting 
monitoring (PDM) plan. We considered all comments and information we 
received during the public comment period on the proposed delisting 
rule and the draft PDM plan when developing this final rule.

Previous Federal Actions

    On October 24, 2019, we published a proposed rule to remove the 
Interior least tern from the Federal List of Endangered and Threatened 
Wildlife (84 FR 56977). Please refer to that proposed rule for a 
detailed description of previous Federal actions concerning this 
species. The proposed rule and supplemental documents are provided at 
http://www.regulations.gov under Docket No. FWS-R4-ES-2018-0082 or at 
https://www.fws.gov/mississippiES/.

Species Information

Taxonomy and Genetics

    Least terns within the Interior Basin of North America were 
described as Sterna antillarum athalassos, a subspecies of the eastern 
least tern (S. antillarum antillarum) (Burleigh and

[[Page 2565]]

Lowery 1942, pp. 173-177). In 2006, the American Ornithologist's Union 
recognized least terns under a previously published genus (Sternula) 
based on mitochondrial DNA phylogeny (Bridge et al. 2005, p. 461). 
Interior least tern was one of three subspecies of New World (North and 
South America) least terns previously recognized by the American 
Ornithologists' Union (1957, p. 239), including the eastern least tern 
and the California least tern (S. antillarum browni). However, due to 
taxonomic uncertainty surrounding least tern subspecies at the time of 
listing (50 FR 21784; May 28, 1985), we treated the Interior least tern 
as a population of eastern least tern.
    Since that time, genetic analyses of North American populations of 
least tern found no evidence of differentiation warranting subspecies 
recognition (e.g., Whittier 2001, p. 10; Draheim et al. 2010, pp. 813-
815; Draheim et al. 2012, p. 146). Genetic exchange between eastern 
least terns and Interior least terns is occurring at a rate greater 
than three migrants per generation between populations (Whittier et al. 
2006, p. 179). After reviewing the best available scientific 
information regarding the taxonomy of the Interior least tern, we 
continue to conclude that it is a distinct population segment of the 
eastern least tern (Sternula antillarum).

Species Description

    Least terns are the smallest members of the family Laridae, 
measuring 21 to 23 centimeters (cm) (8 to 9 inches (in)) long with a 
56-cm (22-in) wingspan (Thompson et al. 1997, pp. 1-2). Sexes look 
alike, characterized in the breeding plumage by a black crown, white 
forehead, grayish back and dorsal wing surfaces, snowy white 
undersurfaces, orange legs, and a black tipped yellow bill. Immature 
birds have darker plumage, a dark bill, and dark eye stripes on their 
white heads. Least terns are distinguished from all other North 
American terns by their small size. Interior least terns can only be 
separated from eastern and California least terns by the geographic 
area used for nesting.

Life Span

    Interior least terns are potentially long-lived, with records of 
recapture more than 20 years following banding (Thompson et al. 1997, 
p. 15); however, the average life span is probably less.

Nesting Habitat and Behavior

    Least terns begin breeding and nesting in their second or third 
year and breed annually throughout their lives (Thompson et al. 1997, 
p. 15). Prior to nesting, young birds exhibit some level of prospecting 
behavior (exploratory dispersal) across the landscape (e.g., Boyd and 
Thompson 1985, p. 405; Lott 2012, p. 12; Shigeta in litt. 2014, 
entire).
    Interior least terns generally nest on the ground, in open areas, 
and near appropriate feeding habitat (Lott and Wiley 2012, pp. 9-11). 
Nests are simple scrapes in the sand, and nesting sites are 
characterized by coarser and larger substrate materials, more debris, 
and shorter and less vegetation compared to surrounding areas (Smith 
and Renken 1993, p. 501; Stucker 2012, p. 49). Typical least tern 
clutch size is reported as two to three eggs (Thompson et al. 1997, p. 
15); however, clutch size may vary by location and year (e.g., Szell 
and Woodrey 2003, p. 37; Jones 2012, p. 3).
    Natural nesting habitat features are maintained and influenced by 
magnitude and timing of riverine flood events (Sidle et al. 1992, p. 
134; Renken and Smith 1995, pp. 194-195; Pavelka in litt. 2012, p. 2). 
The Interior least tern prefers vegetation-free sand or gravel islands 
for nesting, although sand banks, point bars, salt flats or plains, and 
beaches may also be used. Interior least terns prefer areas remote from 
trees or other vegetation that may hide or support predators (Lott and 
Wiley 2012, pp. 9-11). Least terns also nest on anthropogenic sites 
(originating from human activity) (Jackson and Jackson 1985, p. 57; 
Lott 2006, p. 10) near water bodies that contain appropriate and 
abundant prey fishes. Anthropogenic sites used by the tern include 
industrial sites (Ciuzio et al. 2005, p. 102; Mills 2012, p. 2), dredge 
spoil (Ciuzio et al. 2005, p. 102), sand pits (Smith 2008, p. 2), 
constructed habitats (Stucker 2012, pp. 59-66), and rooftops (Boland 
2008, entire; Watterson 2009, entire).
    Lott and Wiley (2012, pp. 9-11) described five physical and 
biological conditions that are necessary for Interior least tern nest 
initiation and successful reproduction:
    (1) Nest sites that are not inundated (flooded) during egg laying 
and incubation;
    (2) Nesting sites that are not inundated until chicks can fly;
    (3) Nesting sites with less than 30 percent ground vegetation;
    (4) Nesting sites that are more than 76 meters (m) (250 feet (ft)) 
from large trees; and
    (5) Availability of prey fishes to support chick growth until 
fledging.
    Interior least terns are colonial nesters. Colony size may vary 
from a few breeding birds to more than 1,200 (Jones 2012, p. 3). 
Populations in some river drainages may be limited by annual 
availability of nesting habitat (e.g., Missouri River; Stucker 2012, p. 
104), while potential nesting habitat is generally abundant and 
underused in other drainages (e.g., Mississippi River; U.S. Army Corps 
of Engineers (USACE) 2008, pp. 10-13). Nesting site conditions (e.g., 
habitat suitability, flood cycles, prey fish abundance, predation 
pressure) can vary significantly from year to year in all drainages, 
resulting in wide fluctuations in bird numbers (Jones 2012, p. 14) and/
or nesting success (Smith and Renken 1993, p. 41; Lott and Wiley 2012, 
p. 15). However, Interior least terns may re-nest, or relocate and re-
nest, if nests or chicks are destroyed early in the season (Massey and 
Fancher 1989, pp. 353-354; Thompson et al. 1997, p. 15). Interior least 
tern chicks leave their nests within a few days of hatching 
(semiprecocial), but remain near the nests and are fed by their parents 
until fledging (Thompson et al. 1997, pp. 14-15).

Food and Foraging Habitat

    Interior least terns are primarily piscivores (fish-eaters), and 
feed opportunistically on small fish species or the young of larger 
fish species. Prey species include native species such as shad 
(Dorosoma spp.), carps and minnows (Cyprinidae), freshwater drum 
(Aplodinotus grunniens), largemouth bass (Micropterus salmoides), white 
bass (Morone chrysops), sunfishes (Lepomis spp.), and top minnows 
(Fundulus spp.), as well as invasive species such as silver and bighead 
carp (Hypophthalmichthys spp.) (USACE 2008, pp. 16, 26). On the 
Missouri River, prey species include emerald shiner (Notropis 
atherinoides), sand shiner (Notropis stramineus), spotfin shiner 
(Cyprinella spiloptera), and bigmouth buffalo (Ictiobus cyprinellus) 
(Stucker 2012, p. 6). Least terns will also occasionally feed on 
aquatic or marine invertebrates (Thompson et al. 1997, pp. 6-7). 
Riverine foraging habitats and fish abundance may be influenced by 
stochastic (random) hydrological conditions and events (i.e., flow, and 
flood timing and magnitude), and channel engineering (Schramm 2004, pp. 
307, 321-323).
    In the Missouri River drainage, Interior least terns forage for 
fish in shallow water habitats and within 12 kilometers (km) (7 miles 
(mi)) from colony sites (Stucker 2012, p. 24). In the Lower Mississippi 
River, foraging terns have been observed feeding in a variety of 
habitats within 3 km (2 mi) of colony sites (Jones 2012, pp. 5-6).

[[Page 2566]]

Migration and Winter Habitat

    Interior least tern fall migrations generally follow major river 
basins to their confluence with the Mississippi River and then south to 
the Gulf of Mexico; however, late summer observations of least terns 
more than 150 km (93 mi) from major river drainages indicate that some 
birds migrate over land (Thompson et al. 1997, p. 16). Interior least 
terns gather in flocks in August prior to migration. Once they reach 
the Gulf Coast, they cannot be distinguished from other least tern 
populations en route to, or within, their winter habitats (i.e., Gulf 
of Mexico, Caribbean islands, Central and South America); therefore, 
the limited information on migration and winter habitat is inclusive of 
other populations (i.e., Caribbean, Gulf Coast, East Coast). Least 
terns appear to migrate in small, loose groups along or near shore, 
feeding in shallows and resting onshore (Thompson et al. 1997, pp. 4-
6). Very little is known of least tern winter habitats, other than that 
the birds are primarily observed along marine coasts, in bays and 
estuaries, and at the mouths of rivers (Thompson et al. 1997, p. 6).

Breeding/Natal Site Fidelity and Dispersal

    Breeding-site fidelity for least terns varies in different 
populations and breeding areas. Return rates of banded adults to the 
sites where they were banded was 36 to 86 percent in California 
colonies; 42 percent on the Mississippi River; 28 percent on the 
central Platte River, Nebraska; and 81 percent at Quivira National 
Wildlife Refuge in Kansas and on the Cimarron River in Oklahoma 
(Thompson et al. 1997, p. 16). Fidelity to natal site is also variable 
and difficult to estimate because re-sightings or recaptures of terns 
banded as chicks have been limited. Estimates of natal site fidelity 
have varied from 5 percent on the Mississippi River, to 82 percent in 
Kansas and Oklahoma (Thompson et al. 1997, p. 16).
    Site fidelity in least terns may be affected by physical habitat 
variables or the extent and type of predation (Atwood and Massey 1988, 
p. 394). As noted above, least terns are strong fliers and can relocate 
if conditions on natal or previous-year nesting grounds become 
unfavorable. A study of eastern least terns found an average 22 percent 
turnover rate in nesting colony sites, primarily due to changes in 
habitat condition or disturbance (Burger 1984, p. 66).
    Lott et al. (2013, pp. 3617-3618) found that 50 to 90 percent of 
reported recaptures occurred less than 26 km (16 mi) from the original 
banding sites, while more than 90 percent dispersed less than 96 km (59 
mi), indicating a high degree of adult site fidelity and natal site 
philopatry (remaining near their point of origin). However, long 
distance dispersal (up to 1,000 km; 621 mi) has been documented (e.g., 
Renken and Smith 1995, pp. 196-198; Boyd and Sexson 2004, p. 88; Lott 
et al. 2013, pp. 3617-3618), and may not be uncommon (Boyd and Thompson 
1985, p. 405). Least tern nesting has also been documented in Brazil 
(Rodrigues et al. 2010, entire) and Hawaii (Conant et al. 1991, entire; 
Pyle et al. 2001, entire). During 2014, an Interior least tern banded 
in the Missouri River drainage was captured in Japan, along with 
another unbanded tern (Shigeta in litt. 2014).

Predation

    Interior least tern eggs, chicks, and adults are prey for a variety 
of mammal and bird predators. Reported predators include birds (e.g., 
crows, herons, owls, and hawks), mammals (e.g., fox, coyote, racoon, 
and skunk), and catfish, as well as domesticated and feral dogs and 
cats (Thompson et al. 1997, pp. 10-11). The cryptic coloration of eggs 
and chicks, the secretive behavior of chicks, and the mobbing behavior 
(attack flights on potential predators) of adults, all serve to protect 
eggs and chicks from predators (Thompson et al. 1997, p. 11).
    Location and size of nesting colonies also has a significant 
influence on degree of predation. Interior least tern reproductive 
success is higher on island colonies as compared to connected sandbar 
colonies, and when water levels maintain isolation of islands and 
nesting bars from mammalian predators (Smith and Renken 1993, p. 42; 
Szell and Woodrey 2003, p. 41). Additionally, significantly higher 
rates of predation were documented in larger colonies compared to 
smaller colonies (Burger 1984, p. 65).

Historical Distribution and Abundance

    The Service defined the historical breeding range of the Interior 
least tern to include the Colorado (in Texas), Red, Rio Grande, 
Arkansas, Missouri, Ohio, and Mississippi Rivers systems from Montana 
south to Texas, and from New Mexico east to Indiana (50 FR 21784; May 
28, 1985). However, in order to avoid confusion with eastern least 
tern, the Service excluded the Mississippi River south of Baton Rouge, 
Louisiana, the Texas Coast, and a 50-mile zone inland from the coast of 
Texas from the protected range of Interior least tern (50 FR 21784, May 
28, 1985, p. 21789).
    The historical distribution and abundance of the Interior least 
tern within this range is poorly documented. Hardy (1957, entire) 
provided the first information on least tern distribution on large 
interior rivers, documenting records of occurrence and nesting in the 
Mississippi, Ohio, Missouri, Arkansas, and Red River drainages. Downing 
(1980, entire) published results from a rapid aerial/ground survey of a 
subset of these rivers, identifying additional nesting populations 
within the range noted above, and estimated the Interior least tern 
population at approximately 1,250 adult birds. Ducey (1981, pp. 10-50) 
doubled the number of known nesting sites, including areas between the 
scattered observations reported in Hardy (1957, entire). Ducey also 
extended the northern distribution of the Interior least tern to 
include the Missouri River below Garrison Dam in North Dakota and Fort 
Peck Dam in Montana. These three publications (Hardy 1957, entire; 
Downing 1980, entire; Ducey 1981, entire) provide the primary 
historical sources of information about the Interior least tern's 
geographic range, and were used to reach the estimate of 1,400 to 1,800 
adults rangewide in the listing rule (50 FR 21784; May 28, 1985).

Current Distribution and Abundance

    The current east to west distribution of summer nesting Interior 
least terns encompasses more than 18 degrees of longitude, or 1,440 km 
(900 mi), from the Ohio River, Indiana and Kentucky, west to the Upper 
Missouri River, Montana. The north to south distribution encompasses 
over 21 degrees of latitude (more than 2,300 km (1,450 mi)) from 
Montana to southern Texas. Interior least terns currently nest along 
more than 4,600 km (2,858 mi) of river channels across the Great Plains 
and the Lower Mississippi Valley (Lott et al. 2013, p. 3623), with 
nesting colonies found in 18 States, including: Montana, North Dakota, 
South Dakota, Nebraska, Colorado, Iowa, Kansas, Missouri, Illinois, 
Indiana, Kentucky, New Mexico, Oklahoma, Arkansas, Tennessee, Texas, 
Louisiana, and Mississippi. As noted above, this does not include least 
tern colonies nesting along the coasts of Texas, Louisiana, and 
Mississippi.
    Rangewide surveys in 2005 estimated an approximate minimum adult 
population size of 17,500, with nesting occurring in more than 480 
colonies spread across 18 States, which is likely an underestimate 
given imperfect detection of adults and survey coverage of potential 
habitat (Lott 2006, pp. 10-21, 50). Lott (2006, pp. 13-15) also

[[Page 2567]]

provided counts for 21 populations or population segments that were 
unknown at the time of listing, which collectively support more than 
2,000 terns.

Population Trends

    The Interior least tern has demonstrated a positive population 
trend, increasing by almost an order of magnitude (or 10 times what it 
was prior) since it was listed in 1985. After it was listed, 
researchers increased survey effort and the geographical extent of the 
area surveyed, producing sufficient Interior least tern count data to 
analyze population trends for several river reaches that support 
persistent breeding colonies. Kirsch and Sidle (1999, p. 473) reported 
a rangewide population increase to over 8,800 adults in 1995, and found 
that 29 of 31 Interior least tern locations with multi-year monitoring 
data were either increasing or stable. Lott (2006, p. 50) reported an 
increase to over 17,500 adult birds in 2005, forming 489 colonies in 68 
distinct geographic sites. While some proportion of the rangewide 
increase in adult bird counts and number of nesting colonies are likely 
attributable to increased survey efforts and improved survey 
techniques, both Kirsch and Sidle (1999, p. 473), and Lott and Sheppard 
(2017a, pp. 50-52) documented multiple drainage population increases 
using multi-year counts.
    Lott (2006, p. 92) conceptualized the Interior least tern 
functioning as a large metapopulation (a regional group of connected 
populations of a species), which might also include least terns on the 
Gulf Coast. Using available information on dispersal of least terns, 
Lott et al. (2013, pp. 3616-3617) defined 16 discrete breeding 
populations of Interior least tern, with 4 major geographical breeding 
populations (population complexes) accounting for more than 95 percent 
of all adult birds and nesting sites throughout the range. Portions of 
these four population complexes have experienced multi-year monitoring 
to different degrees. While some local (colony, subpopulation) declines 
have been documented, the Interior least tern has experienced a 
dramatic increase in range and numbers since listing and development of 
the recovery plan (e.g., Kirsch and Sidle 1999, p. 473; Lott 2006, pp. 
10-49). There has been no reported extirpation of any population or 
subpopulation since the species was listed in 1985.

Recovery Criteria

    Section 4(f) of the Act directs us to develop and implement 
recovery plans for the conservation and survival of endangered and 
threatened species unless we determine that such a plan will not 
promote the conservation of the species. Recovery plans must, to the 
maximum extent practicable, include ``objective, measurable criteria 
which, when met, would result in a determination, in accordance with 
the provisions [of section 4 of the Act], that the species be removed 
from the list.''
    Recovery plans provide a roadmap for us and our partners on methods 
of enhancing conservation and minimizing threats to listed species, as 
well as measurable criteria against which to evaluate progress towards 
recovery and assess the species' likely future condition. However, they 
are not regulatory documents and do not substitute for the 
determinations and promulgation of regulations required under section 
4(a)(1) of the Act. A decision to revise the status of a species, or to 
delist a species is ultimately based on an analysis of the best 
scientific and commercial data available to determine whether a species 
is no longer an endangered species or a threatened species, regardless 
of whether that information differs from the recovery plan.
    There are many paths to accomplishing recovery of a species, and 
recovery may be achieved without all of the criteria in a recovery plan 
being fully met. For example, one or more criteria may be exceeded 
while other criteria may not yet be accomplished. In that instance, we 
may determine that the threats are minimized sufficiently and the 
species is robust enough that it no longer meets the definition of an 
endangered species or a threatened species. In other cases, we may 
discover new recovery opportunities after having finalized the recovery 
plan. Parties seeking to conserve the species may use these 
opportunities instead of methods identified in the recovery plan. 
Likewise, we may learn new information about the species after we 
finalize the recovery plan. The new information may change the extent 
to which existing criteria are appropriate for identifying recovery of 
the species. The recovery of a species is a dynamic process requiring 
adaptive management that may, or may not, follow all of the guidance 
provided in a recovery plan.
    The Service approved the Interior Least Tern Recovery Plan on 
September 19, 1990 (Service 1990, entire). The objective of the 
recovery plan was to establish standards for recovery that may lead to 
delisting the Interior least tern. Recovery criteria are the values by 
which it is determined that a recovery plan objective has been reached. 
Recovery criteria identified in the recovery plan were designed to 
assure the protection of essential habitat by removal of threats at 
that time and habitat enhancement, establish agreed-upon management 
plans, and attain a rangewide population of 7,000 birds at the levels 
listed below (for five major river drainages throughout the Interior 
least tern's range):
    (1) Adult birds in the Missouri River system will increase to 
2,100, and remain stable for 10 years.
    (2) Current numbers of adult birds (2,200-2,500) on the Lower 
Mississippi River will remain stable for 10 years.
    (3) Adult birds in the Arkansas River system will increase to 
1,600, and remain stable for 10 years.
    (4) Adult birds in the Red River system will increase to 300, and 
remain stable for 10 years.
    (5) Current numbers of adult birds (500) in the Rio Grande River 
system will remain stable for 10 years.
    Primary recovery tasks conducted to achieve the recovery objective 
and drainage population targets included:
    (1) Determining the distribution and population trends of the 
Interior least tern;
    (2) Determining habitat requirements and status;
    (3) Protecting, enhancing, and increasing Interior least tern 
populations; and
    (4) Preserving and enhancing the tern's habitats.
    These are briefly reviewed below.

Rangewide Population Criterion to Delist

    The Interior least tern rangewide numerical recovery criterion 
(7,000 birds) has been met and has been exceeded since 1994 (see 
Service 2013, pp. 7-127). Using rangewide seasonal count data from 1984 
(722 terns) through 1995 (8,859 terns), Kirsch and Sidle (1999, pp. 
473-477) demonstrated achievement of the numerical recovery criterion 
and a positive population growth trend. They noted that most of the 
Interior least tern increase had occurred on the Lower Mississippi 
River, observed that population increases were not supported by 
fledgling success estimates available at that time, and hypothesized 
that Interior least tern increases were possibly due to immigration 
surges from a more abundant least tern population inhabiting the Gulf 
Coast (Kirsch and Sidle 1999, p. 478).
    Lott (2006, entire) organized, compiled, and reported a 
synchronized rangewide count for Interior least tern in 2005, finding 
tern numbers had doubled

[[Page 2568]]

since 1995 (17,591 birds rangewide; 62 percent occurring along the 
Lower Mississippi River), equaling or exceeding least tern population 
estimates along the U.S. Gulf Coast (Lott 2006, p. 50). Since 2006, the 
majority of Interior least terns continue to be reported from the Lower 
Mississippi River (Service 2013, p. 11). As did Kirsch and Sidle (1999, 
p. 478), Lott (2006, p. 52) also hypothesized a wider least tern 
metapopulation, which included Gulf Coast and interior subpopulations, 
and the possibility of a shift of birds from the Gulf Coast to inland 
habitats due to the presence of better nesting conditions, particularly 
on the Lower Mississippi River. However, there are few data directly 
supporting the Kirsch and Sidle (1999, pp. 473-477) or the Lott (2006, 
p. 52) immigration hypotheses as a factor in the 20-year increase in 
Interior least tern counts. There has not been a complete or organized 
rangewide count since 2005; however, some geographic segments continue 
to be annually monitored, including portions of the Missouri (USACE in 
litt. 2017, entire), Platte (Keldsen and Baasch 2016, entire), Red 
(Stinson in litt. 2017, entire), Arkansas (Cope in litt. 2017, entire; 
Nupp 2016, entire), and Wabash Rivers (Mills 2018, entire). These 
partial counts indicate that we continue to exceed the recovery goal of 
7,000 birds (Service 2013, pp. 11-12).

Numerical Population Targets

    In addition to the numerical population targets identified in the 
recovery plan for five major river drainages throughout the tern's 
range (see above), sub-drainage targets were also identified for the 
Missouri and Arkansas River drainages (Service 1990, pp. 28-29). 
Drainage and sub-drainage numerical targets were based upon the 
opinions of technical experts and State and Federal resource agencies 
of the potential for population increase at the time (Service 1990, p. 
28). The drainage system population size targets have been exceeded in 
three of the five targeted drainages (Lower Mississippi (more than 25 
years), Red (more than 15 years), and Arkansas Rivers (more than 10 
years) (see Service 2013, pp. 22-26). As to the Rio Grande drainage, it 
is now recognized that the subpopulations found within the drainage 
represent recent exploitation of anthropogenic habitats (i.e., salt 
flats and reservoirs) and are not historical habitats; thus, these 
areas were inappropriately designated as ``essential'' segments of the 
tern's ecosystem in the recovery plan (Service 2013, pp. 26-27). 
Therefore, numerical targets originally set for the Rio Grande drainage 
are no longer considered necessary for this species' recovery.
    As to the Missouri River drainage, the Interior least tern 
population size has remained relatively stable (approximately 1,600 
birds) over the 29 years since recovery criteria were identified 
(Service 2013, p. 11), and neither the drainage population target 
(2,100) nor many of the targets identified for Missouri River drainage 
segments have been consistently met (Service 2013, pp. 14-21). However, 
since the tern was listed, the Missouri River system has received a 
significant commitment of conservation attention and resources (USACE 
2017a, pp. 1-17), particularly in comparison to other drainages that 
have experienced increases in tern populations. Based on the lack of 
increase in population, in light of the substantial commitment of 
resources, we conclude that that the Missouri River drainage is likely 
at the carrying capacity of the available habitat (Service 2013, pp. 
14-21), and the recovery goal of 2,100 birds is not achievable. 
Periodic downward trends observed in a few Missouri drainage 
subpopulations have been reversed by habitat improvement following 
major floods (Pavelka 2012, p. 2), or offset by upward trends in other 
subpopulations (Pavelka 2012, pp. 7-8; Lott and Sheppard 2017a, pp. 49-
53), indicating that the Missouri River drainage Interior least tern 
population is sustainable and recovered.
    In short, some drainage population targets identified in the 1990 
recovery plan have not been fully met, as the Rio Grande was 
inappropriately considered ``essential'' (see above) and the Missouri 
River drainage appears to be at carrying capacity and incapable of 
reaching the 2,100 target identified in the recovery plan. However, the 
inability to meet these drainage and sub-drainage targets have been 
offset by large increases in the Interior least tern populations within 
the Arkansas, Red, and Lower Mississippi Rivers, and by the discovery 
of numerous subpopulation segments throughout the Interior Basin that 
were either unrecognized or not occupied at the time of listing and 
recovery plan development, increasing the number of known breeding 
colonies from a few dozen at listing to more than 480 (Lott 2006, p. 
10; also see Service 2013, pp. 31-33).

Habitat Criteria

    Recovery plan delisting criteria required the protection, 
enhancement, and restoration of essential Interior least tern breeding 
habitats (Service 1990, pp. 28-29). Beyond the identification of 
specific river reaches as ``essential,'' habitat parameters were not 
defined, nor were specific objective and measurable criteria for their 
protection identified. The recovery plan outlined several tasks to 
protect and enhance Interior least tern habitats, including managing 
water flows, modifying construction activities, and protecting all 
areas identified as ``essential'' across the species' range through 
acquisition, easements, or agreements (Service 1990, pp. 29-50).
    Recovery tasks identified for managing water flows are primarily 
relevant to portions of the Missouri, Red, and Arkansas River 
drainages, which cumulatively encompass about 20 percent of the 
Interior least tern breeding population. The majority of the remainder 
of the species' range occurs along unimpounded sections of the 
Mississippi River not subject to flow management. Over the past two 
decades, protective flow management actions have been identified and 
incorporated by USACE Northwest Division into their Missouri River Bank 
Stabilization and Navigation Project and operations of the Missouri 
River Reservoir System, including seasonal reservoir flow management to 
reduce nesting mortalities, and for sandbar augmentation and 
modification, vegetation management, predation control, human 
restriction measures, and water-level management for reservoir nesting 
areas (USACE 2017a, pp. 139-143). In the Southern Plains, USACE 
Southwest Division civil works projects in the Arkansas, Canadian, and 
Red River systems within Arkansas, Oklahoma, and Texas use reservoir 
storage and operation to reduce flooding; minimize land bridging, 
predation, and human disturbance during Interior least tern nesting 
season; and enhance nesting habitats at other times of the year (USACE 
2002, pp. 3-4; 2016, pp. 18-20). These water management practices have 
been adopted by the respective USACE Divisions and Districts as best 
management practices (BMPs) and with commitments to continue into the 
future regardless of the future status of the Interior least tern under 
the Act (USACE 2016, pp. 2, 24; 2018, pp. 4-13-4-17).
    Recovery tasks for modifying construction activities within river 
channels have been successfully implemented across Interior least tern 
habitats that are managed under USACE programs in jurisdictional waters 
(categories of waters defined under the Clean Water Act (33 U.S.C. 1251 
et seq.) that include navigable waters, interstate waters, tributaries, 
impoundments, etc.). Construction practices critical to maintaining and 
protecting nesting

[[Page 2569]]

habitats have been incorporated into USACE river management programs as 
standard operating procedures (SOPs) or BMPs, including construction 
timing and work zone buffers to avoid disturbance of nesting colonies, 
dike modifications to protect and maintain habitat values, and dredge 
material disposal methods beneficial to maintaining nesting sand bars 
and islands (e.g., USACE 2013, pp. 69-72; USACE 2016, p. 21). Other 
SOPs and BMPs incorporated into USACE programs promote ecosystem 
productivity important to tern foraging, including articulated concrete 
mat design, use of hardpoints in lieu of revetment, and strategic 
placement of woody debris within channels (e.g., USACE 2013, p. 71). 
These existing management strategies and programs (USACE 2013, entire; 
2016, entire; 2017a, entire) are protective of waters and habitats 
managed by USACE that support about 80 percent of the Interior least 
tern's range and have been a major factor in the recovery of the 
species. All USACE programs currently provide for adaptive management 
into the future, independent of the Federal listing status of the 
Interior least tern (USACE 2013, p. 71; 2016, pp. 2, 24; 2018, pp. 4-
13-4-17).
    New information developed over the past three decades relative to 
the ecology of Interior least tern and its habitats indicate that 
recovery tasks to protect ``essential'' habitats across the species' 
range through acquisition or easements are neither cost-effective nor 
necessary. Riverine habitat for Interior least terns is not static, and 
clearly experiences dramatic local or regional annual (at times, daily) 
variation in location, quantity, and quality. Describing and 
quantifying habitat quality is difficult, given the wide variety of 
conditions the bird is known to exploit (e.g., rivers, reservoirs, 
rooftops).
    The Interior least tern adjusts to habitat variation and change 
over its range through metapopulation dynamics (Hanski and Gilpin 1991, 
entire; Lott et al. 2013, p. 3620; Lott and Sheppard 2017, entire). A 
metapopulation consists of a network of populations with similar 
dynamics that are buffered against extinction by abandoning areas as 
habitats degrade, and dispersing and exploiting suitable habitats as 
they become available. Therefore, the importance of specific habitat 
segments to the species is likely to change with time. Within large 
metapopulations of mobile species, small subpopulations (or colonies 
within subpopulations) may occur in habitats where recruitment is 
inconsistent or may not exceed mortality (i.e., population sinks), but 
which are maintained by immigration from colonies where recruitment 
exceeds mortality (i.e., population sources). While exploitation of 
anthropogenic habitats by Interior least terns may indicate a lack of 
suitable habitat in an area, it may also indicate an overall population 
or subpopulation expansion. Sink colonies also play important roles in 
large metapopulations by providing opportunities for range expansion, 
and/or redundancy from episodic stochastic impacts to preferred natural 
habitats. While some colony sites may be periodic or consistent 
population sinks, there is no evidence that they are detracting from 
the Interior least tern's rangewide survival (e.g., Lott and Sheppard 
2017a, p. 51), particularly in consideration of the substantial 
increase in the known number and size of tern colonies over the past 
two decades, and the expansion of the species' distribution outside of 
its historical range (i.e., Illinois, New Mexico, central Texas, 
Colorado; see Service 2013, pp. 31-33).
    Based upon this understanding of Interior least tern population 
dynamics and habitat use, the recovery task of protecting all areas 
identified in 1990 as ``essential'' across the species' range through 
acquisition or easements is not necessary for the conservation of the 
species. This conclusion is supported by the increase in the species' 
range and abundance over the past 30 years without protections achieved 
through such acquisition or easements. Although some Interior least 
tern nesting colonies occur on protected public lands such as National 
Wildlife Refuges, they represent only a small portion (less than 2 
percent) of the rangewide population. Additionally, as noted above, 
existing management agreements, strategies, and programs within 
jurisdictional waters are protective of the habitats that support about 
80 percent of the Interior least tern population (USACE 2013, entire; 
2016, entire; 2017, entire).
    While the majority (80 percent) of Interior least tern nesting 
colonies are known from jurisdictional waters with a strong Federal 
connection with navigation systems or reservoirs, the remaining nesting 
colonies occur along rivers with a more limited Federal nexus, or on 
mining and industrial sites adjacent to or near rivers and reservoirs. 
On about 10 percent of these, Federal, State, and/or private 
conservation partnerships have developed and implemented conservation 
agreements and management programs beneficial to Interior least tern as 
well as other at-risk or endangered species. These programs generally 
post or restrict access, control predators, and conduct monitoring 
during nesting season, as well as conduct vegetation control and public 
education as opportunities present.
    In the Platte River drainage, the Tern and Plover Conservation 
Partnership was initiated in 1999, at the University of Nebraska, 
School of Natural Resources. This partnership consists of a group of 
State, industrial, Federal, and other cooperators having an interest in 
tern and plover conservation and management on and along the Platte, 
Loup, and Elkhorn Rivers, with emphasis on nesting areas associated 
with sand and gravel mines, lake shore housing developments, and 
dredging operations (University of Nebraska-Lincoln 2019, entire). 
Long-term management of Interior least tern habitats in the Platte 
River drainage is also assured by an adaptive management plan developed 
and implemented by a partnership of State and industrial water users in 
Nebraska, Colorado, and Wyoming under the Platte River Recovery 
Implementation Program (Platte River Recovery Implementation Program 
2019, entire). This program, initiated in 1997, also targets management 
needs of the endangered pallid sturgeon (Scaphirhynchus albus) and 
whooping crane (Grus americana), and the threatened piping plover 
(Charadrius melodus). Since both programs target other listed species 
with similar habitat requirements, and the Interior least tern is 
State-listed as endangered, these conservation programs and efforts are 
expected to continue regardless of a change in the Federal status of 
this species.
    Interior least tern management in the Wabash River drainage began 
with the 1986 discovery of a single nesting pair on Gibson Generating 
Station property, Gibson County, Indiana (Hayes and Pike 2011, entire; 
Mills 2018, pp. 2-5). This colonization led to site monitoring, 
predator control, and other protective measures, including vegetation 
control, water management, and habitat management and creation, 
resulting in increasing numbers of terns and expansion of nesting 
colonies to multiple sites on public and private properties in the 
vicinity (Hayes and Pike 2011, entire). In 1999, management was 
formalized by development of a habitat conservation plan, which was 
renewed and revised in 2004, 2011, and 2018, by Duke Energy Corporation 
(Hayes and Pike 2011, entire). The Indiana Nongame and Endangered 
Wildlife Program continues to coordinate conservation and monitoring 
efforts on industrial and river sites along

[[Page 2570]]

the Wabash River by Duke Energy, the Service, and other Indiana 
Department of Natural Resources personnel and contractors (Mills 2018, 
p. 14). Since the Interior least tern may continue to be protected by 
the State of Indiana, management and monitoring is expected to continue 
to some degree, regardless of a change in the Federal status of 
species.
    To various degrees, a number of additional small, localized, and 
often temporary breeding colonies of Interior least tern and their 
habitats have been managed, protected, and monitored at industrial, 
municipal, and reservoir sites under the Act's conservation (sections 
6, 7(a)(1), and 10) or consultation (section 7(a)(2)) requirements. 
Managed sites have included coal mines (e.g., Tanner and Hart 1998, 
entire), rooftops (e.g., Boylan 2008, entire), and small reservoirs 
(e.g., Nelson 2010, entire). Such efforts may or may not continue when 
the tern is delisted; however, it is also likely that the tern will 
continue to exploit small areas of suitable habitats as they are 
available and encountered in its range. While such populations 
contribute some small benefit to the rangewide redundancy and 
representation of the tern (see discussion of Population Trends, 
above), they cumulatively represent less than 2 percent of the summer 
nesting population and their success or failure within individual sites 
has little impact on the rangewide conservation status of the Interior 
least tern.
    In summary, the expansion of the numbers and distribution of the 
Interior least tern, and its adaptation to and exploitation of 
anthropogenic habitats over the past several decades, indicate that the 
species is no longer conservation-reliant. Potential threats identified 
at the time of listing have been removed or ameliorated by conservation 
actions of multiple conservation partners, most principally the USACE, 
for more than 20 years. These actions have assisted in recovery of the 
species as reflected in the large number of individuals rangewide, 
stable to increasing drainage populations since listing, and a high 
number of self-sustaining colonies in 18 States. Furthermore, our 
partners in USACE Divisions and Districts within the range of the 
Interior least tern have cooperatively modified their programs to 
provide for the long-term management of nesting and foraging habitats 
for about 80 percent of the rangewide population of the species (USACE 
2013, entire; 2016, entire; 2017, entire). Another 10 percent of the 
population is managed by State and private partnerships, which are 
expected to continue based upon State status and regulations. Regarding 
the remaining 10 percent of the population that nest in habitats with 
minimal or no management, while these areas contribute to redundancy 
and representation for the species, their success or failure within 
these sites is not essential to the continued existence of the Interior 
least tern.

Summary of Factors Affecting the Species

    Section 4 of the Act (16 U.S.C. 1533) and its implementing 
regulations (50 CFR part 424) set forth the procedures for determining 
whether a species is an ``endangered species'' or a ``threatened 
species.'' The Act defines an ``endangered species'' as a species that 
is in danger of extinction throughout all or a significant portion of 
its range, and a ``threatened species'' as a species that is likely to 
become an endangered species within the foreseeable future throughout 
all or a significant portion of its range. The Act requires that we 
determine whether any species is an ``endangered species'' or a 
``threatened species'' because of any of the following factors:
    (A) The present or threatened destruction, modification, or 
curtailment of its habitat or range;
    (B) Overutilization for commercial, recreational, scientific, or 
educational purposes;
    (C) Disease or predation;
    (D) The inadequacy of existing regulatory mechanisms; or
    (E) Other natural or manmade factors affecting its continued 
existence.
    These factors represent broad categories of natural or human-caused 
actions or conditions that could have an effect on a species' continued 
existence. In evaluating these actions and conditions, we look for 
those that may have a negative effect on individuals of the species, as 
well as other actions or conditions that may ameliorate any negative 
effects or may have positive effects.
    We use the term ``threat'' to refer in general to actions or 
conditions that are known to or are reasonably likely to negatively 
affect individuals of a species. The term ``threat'' includes actions 
or conditions that have a direct impact on individuals (direct 
impacts), as well as those that affect individuals through alteration 
of their habitat or required resources (stressors). The term ``threat'' 
may encompass--either together or separately--the source of the action 
or condition or the action or condition itself.
    However, the mere identification of any threat(s) does not 
necessarily mean that the species meets the statutory definition of an 
``endangered species'' or a ``threatened species.'' In determining 
whether a species meets either definition, we must evaluate all 
identified threats by considering the expected response by the species, 
and the effects of the threats--in light of those actions and 
conditions that will ameliorate the threats--on an individual, 
population, and species level. We evaluate each threat and its expected 
effects on the species, then analyze the cumulative effect of all of 
the threats on the species as a whole. We also consider the cumulative 
effect of the threats in light of those actions and conditions that 
will have positive effects on the species--such as any existing 
regulatory mechanisms or conservation efforts. The Secretary of the 
Interior (Secretary) determines whether the species meets the 
definition of an ``endangered species'' or a ``threatened species'' 
only after conducting this cumulative analysis and describing the 
expected effect on the species now and in the foreseeable future.
    We must consider these same five factors in delisting a species. We 
may delist a species according to 50 CFR 424.11(e) if the best 
available scientific and commercial data indicate that: (1) The species 
is extinct; (2) the species does not meet the definition of an 
endangered species or a threatened species; or (3) the listed entity 
does not meet the statutory definition of a species.
    A recovered species is one that no longer meets the Act's 
definition of endangered species or threatened species. Determining 
whether a species is recovered requires consideration of the same five 
categories of threats specified in section 4(a)(1) of the Act. For 
species that are already listed as endangered or threatened, this 
analysis of threats is an evaluation of both the threats currently 
facing the species and the threats that are reasonably likely to affect 
the species in the foreseeable future following delisting or 
downlisting (i.e., reclassification from endangered to threatened) and 
the removal or reduction of the Act's protections.
    The Act does not define the term ``foreseeable future,'' which 
appears in the statutory definition of ``threatened species.'' Our 
implementing regulations at 50 CFR 424.11(d) set forth a framework for 
evaluating the foreseeable future on a case-by-case basis. The term 
foreseeable future extends only so far into the future as we can 
reasonably determine that both the future threats and the species' 
responses to those

[[Page 2571]]

threats are likely. In other words, the foreseeable future is the 
period of time in which we can make reliable predictions. ``Reliable'' 
does not mean ``certain''; it means sufficient to provide a reasonable 
degree of confidence in the prediction. Thus, a prediction is reliable 
if it is reasonable to depend on it when making decisions.
    It is not always possible or necessary to define foreseeable future 
as a particular number of years. Analysis of the foreseeable future 
uses the best scientific and commercial data available and should 
consider the timeframes applicable to the relevant threats and to the 
species' likely responses to those threats in view of its life-history 
characteristics. Data that are typically relevant to assessing the 
species' biological response include species-specific factors such as 
lifespan, reproductive rates or productivity, certain behaviors, and 
other demographic factors.
    In considering the foreseeable future as it relates to the status 
of the Interior least tern, we consider the factors affecting the 
species and historical abundance trends. Our period of record for 
monitoring the species and its associated habitat is over three 
decades, which, when combined with our knowledge of factors affecting 
the species, allows us to reasonably predict future conditions. We 
think it is reasonable to define the foreseeable future for the 
Interior least tern to be 30 years based on analysis of these factors 
and as presented in more detail under Future Conditions and Species 
Viability, below.
    When the Interior least tern was listed as endangered in 1985, the 
identified threats (factors) influencing its status were the 
modification and loss of habitat and curtailment of range (Factor A), 
predation and disturbance of local colonies (Factor C), and the 
inadequacy of State or Federal mechanisms to protect its habitat at 
that time (Factor D). The following analysis, based on an assessment of 
the Interior least tern, evaluates these previously identified threats, 
any other threats currently facing the species, and those threats that 
are reasonably likely to affect the Interior least tern in the 
foreseeable future following the delisting and the removal of the Act's 
protections.

Habitat Loss and Curtailment of Range

    The primary threats identified for the Interior least tern in the 
1985 final listing rule were associated with the destruction and 
modification of habitat due to channel engineering practices on large 
rivers of the Interior Basin (i.e., damming, channelization, and 
channel stabilization) (50 FR 21784, May 28, 1985, pp. 21789-21790; 
Service 1990, pp. 22-23). Reservoirs had inundated hundreds of miles of 
historical or potential tern riverine habitat in many Mississippi River 
Basin drainages, and reduced sediment input into channels below dams 
had caused channel degradation, constriction, and loss of potential 
nesting habitats. Channelization, channel training structures (dikes), 
and bank stabilization in the Missouri, Mississippi, and Ohio Rivers 
prevented natural geomorphic response to loss of sediments, resulting 
in deepened and narrowed channels, and loss or terrestrialization 
(vegetation encroachment) of potential nesting sandbars and islands. 
Reservoir releases for hydropower, navigation, and flood control also 
were found to adversely affect Interior least tern populations 
surviving below these same dams (Service 1990, p. 22). These trends of 
habitat degradation were also expected to continue throughout most of 
the tern's fragmented range (Smith and Stuckey 1988, entire).
    New information on the species' response to the threats identified 
at the time of listing indicate that anthropogenic changes in some 
river channels supporting the Interior least tern have also benefited 
the Interior least tern in ways that may have compensated for 
historical impacts to its habitat. For example, in the Lower 
Mississippi River (where tern numbers have increased by an order of 
magnitude, and which currently supports more than 60 percent of the 
Interior least tern nesting population), channel engineering, including 
the construction of channel training dikes, resulted in higher sandbars 
as well as earlier and shorter spring and summer high water events in 
this portion of the range (Schramm 2004, pp. 306, 322; USACE 2013, p. 
60). Such changes have reduced egg and chick flood-related mortality 
events, extended the nesting season, and increased re-nesting 
opportunities, all of which may explain the Interior least tern 
population increase in the Lower Mississippi River over the past four 
decades.
    Anthropogenic habitats are also now known to provide significant 
opportunities for Interior least tern nesting and recruitment. High 
flows in the Platte River have historically peaked after most nesting 
has been initiated within the river channel, flooding nests and 
hatchlings, and limiting re-nesting opportunities (Farnsworth et al. 
2017, p. 3587). Models now suggest least tern nesting success would 
only have occurred during 32 percent of years, an inadequate success 
rate to have maintained the species within the Platte River. It is now 
hypothesized that off-channel mining habitats were, and continue to be, 
critical to the success of the Interior least tern in the central and 
lower Platte River (Farnsworth et al. 2017, p. 3588). Similar 
observations have been proposed for some reaches of the Missouri River 
(e.g., Jorgensen 2009, entire). In Texas and Colorado, foraging and 
nesting habitats created by dam construction have provided for Interior 
least tern colonization of arid regions historically unsuitable for the 
species (Service 2013, pp. 26-27).
    Although river channel engineering, including reservoirs, 
channelization, channel training structures, and bank stabilization, 
continues to alter the Interior least tern's habitats, as outlined 
above, these habitat modifications have also created additional habitat 
opportunities for this species. The Interior least tern's known range 
has increased significantly; the reported numbers of nesting Interior 
least terns have expanded by almost an order of magnitude from fewer 
than 2,000 in 1985, to approximately 18,000 in 2005 (Lott 2006, p. 10), 
and currently more than 480 Interior least tern colonies are known to 
occur in four major drainages with 16 primary subpopulations (Lott et 
al. 2013, pp. 3616-3617). Most of these subpopulations have been stable 
or increasing over the past two decades (Lott et al. 2013, p. 3620; 
Lott and Sheppard 2017a, pp. 51-52). Thus, the negative impacts of 
river channel engineering on the tern appear to have been initially 
overestimated.
    Loss of some historical Interior least tern summer nesting habitat 
likely occurred on a local or regional scale prior to listing; however, 
we have found no evidence that nesting habitat loss is currently 
limiting the Interior least tern on a rangewide scale. The Interior 
least tern continues to nest in all habitat types and drainages 
identified in 1985, and there is no evidence of significant regional 
decline or extirpation from any drainage since listing (Service 2013, 
p. 10). As previously noted, the Interior least tern uses a variety of 
anthropogenic habitats such as navigation systems, reservoirs, sand 
mines, and so forth, allowing the Interior least tern to not only 
survive, but also to thrive in some drainages, and even expand its 
range into areas without historical records.
    While future conditions within some portion of the Interior least 
tern's range may deteriorate due to natural or anthropogenic changes 
(for example, climate change may increase the likelihood of heavy 
rainfall events) or human demands (e.g., water extraction

[[Page 2572]]

or removal in the western plains), the wide range of the Interior least 
tern and its ability to relocate to areas with better conditions reduce 
the magnitude of any threat (see Effects of Climate Change, below). The 
Interior least tern is also well adapted to adjust to variability and 
changes in local habitat availability, quality, and quantity through 
metapopulation dynamics (see Habitat Criteria, above, for detail on 
metapopulation dynamics), enhanced by the species' longevity, dispersal 
capability, and ability to re-nest (e.g., Lott et al. 2013, p. 3620; 
Lott and Sheppard 2017b, entire).

Predation

    Interior least tern eggs, chicks, and adult individuals are 
susceptible to a wide variety of avian and terrestrial predators. 
During the 25-year monitoring period on the Missouri River, the 
greatest cause of egg loss has been predation (3 percent) (USACE 2017b, 
spreadsheet line 302). On the Mississippi River, predation was the 
second highest cause of Interior least tern egg, chick, and adult 
mortality (Smith and Renken 1993, pp. 41-42).
    Interior least terns are adapted to avoid predation because: (1) 
Their eggs and chicks are cryptically colored to avoid detection; (2) 
chicks exhibit ``freeze'' behavior when threatened; and (3) adults 
cooperate in alarm calls and attack flights on potential predators to 
the colonies (Thompson et al. 1997, p. 11). Terns may also abandon and 
relocate colonies due to predation pressure (Atwood and Massey 1988, p. 
394).
    The level and effect of predation can be locally high and 
significant in some colonies and in some years; however, the Interior 
least tern's adaptation to high levels of predation is demonstrated by 
the exponential growth of rangewide breeding numbers since listing in 
1985. Interior least tern are long-lived, and current population trends 
indicate that sporadic local breeding failure due to predation or other 
causes is natural, and unlikely to be significant to the long-term 
stability of the rangewide population.

Existing Regulatory Mechanisms

    The Interior least tern is covered by the Migratory Bird Treaty Act 
(MBTA; 16 U.S.C. 703 et seq.). The MBTA makes it unlawful, at any time 
and by any means or in any manner, to pursue, hunt, take, capture, 
kill, attempt to take, capture, or kill, possess, offer for sale, sell, 
offer to barter, barter, offer to purchase, purchase, deliver for 
shipment, ship, export, import, cause to be shipped, exported, or 
imported, deliver for transportation, transport or cause to be 
transported, carry or cause to be carried, or receive for shipment, 
transportation, carriage, or export, any migratory bird, any part, 
nest, or eggs of any such bird, or any product, whether or not 
manufactured, which consists, or is composed in whole or part, of any 
such bird or any part, nest, or egg thereof (16 U.S.C. 703(a)). 16 
U.S.C. 704(a) states that the Secretary is authorized and directed to 
determine when, to what extent, if at all, and by what means, the take 
of migratory birds should be allowed, such as for educational, 
scientific, and recreational purposes, and to adopt suitable 
regulations permitting and governing the take. In adopting regulations, 
the Secretary is to consider such factors as distribution and abundance 
to ensure that any take is compatible with the protection of the 
species.
    Since the publication of the proposed rule to delist the Interior 
least tern (84 FR 56977; October 24, 2019), the Service published a 
proposed rule to adopt a regulation that defines the scope of the MBTA 
as it applies to conduct resulting in the injury or death of migratory 
birds protected by the MBTA (85 FR 5915; February 3, 2020). This 
proposed regulation, if made final, will define the scope of the MBTA's 
prohibitions to reach only actions directed at migratory birds, their 
nests, or their eggs, and take that is incidental to otherwise lawful 
activities would no longer be prohibited. Therefore, Federal agencies, 
industries, or private parties that have avoided or mitigated for 
incidental take to migratory birds due to MBTA prohibitions will no 
longer be required to do so. The MBTA will continue to protect 
migratory birds, their parts, nests, and eggs from intentional take and 
trade. We have reviewed this information and have evaluated the 
potential effects of these proposed changes on the Interior least tern. 
Incidental take is not currently a primary threat to the rangewide 
status of the Interior least tern, but there is the potential that with 
removal of the protections of the Act and the proposed regulation that 
defines the scope of the MBTA, incidental take may increase in some 
nesting areas. However, as noted herein under Habitat Criteria, above, 
USACE Divisions and Districts within the range of the Interior least 
tern have cooperatively modified their programs to minimize take of 
Interior least terns, and to provide for the long-term management of 
the nesting and foraging habitats across about 80 percent of the range 
of the species (USACE 2013, entire; 2016, entire; 2017, entire). USACE 
has also committed to continue consideration and management of the 
Interior least tern and its habitats following delisting, because 
maintaining viable populations of Interior least tern is in their 
interest, and that of all Federal agencies. More than 10 percent of the 
Interior least tern population consists of small to moderately sized 
colonies that are managed on Federal or State conservation lands, or 
under State and private partnerships, many of which are expected to 
continue management based upon environmental management objectives or 
State status and regulations. The Service, therefore, finds that should 
the proposed regulation that defines the scope of the MBTA be adopted, 
BMPs and SOPs to avoid incidental take of the tern will continue to be 
implemented across more than 90 percent of the species' range.
    The remaining portion of the Interior least tern population 
consists of numerous, small, scattered, often ephemeral colonies 
nesting in habitats with minimal or no management. Such colonies 
without management commitments may be impacted by the proposed 
regulation that defines the scope of the MBTA. While these areas 
contribute in some small degree to redundancy and representation of the 
species, their success or failure within specific sites is not 
essential to the continued existence of the Interior least tern.
    In summary, incidental take is not currently a primary threat to 
the rangewide status of the Interior least tern, but there is the 
potential that with removal of the protections of the Act and the 
proposed regulation that defines the scope of the MBTA, incidental take 
may increase on some nesting areas. Any adoption of proposed changes to 
reduce the scope of the take provisions of the MBTA is not likely to 
affect management commitments currently in place, which are expected to 
continue following delisting of the Interior least tern, as BMPs and 
SOPs to avoid incidental take of the tern will continue to be 
implemented across more than 90 percent of the species' range. We also 
believe that Federal and State agencies, as well as private industries 
and individuals, recognize that it is in the public interest to 
minimize the impacts of lawful activities to Interior least tern and 
other migratory birds, and the Service shall continue to work with them 
to do so.
    When the Interior least tern was listed in 1985, the listing rule 
(50 FR 21784; May 28, 1985) noted that while the MBTA protected 
migratory birds from harm or harassment, it did not provide a mechanism 
to address habitat threats.

[[Page 2573]]

It concluded, therefore, in the absence of protection under the Act, 
the MBTA and other existing regulatory mechanisms were inadequate to 
prevent deterioration to habitats of the Interior least tern due to 
channel engineering. As noted previously, however, the effects of 
channel engineering on the species may have been more beneficial than 
detrimental, at least in some portions of the range (see Habitat Loss 
and Curtailment of Range, above).
    The protection, restoration, conservation, and management of 
ecological resources within the Interior least tern's range have been 
broadly enhanced through Executive Orders and Federal regulations since 
the species was listed. These include provisions emphasizing the 
protection and restoration of ecosystem function and quality in 
compliance with existing Federal environmental statutes and regulations 
(e.g., under the National Environmental Policy Act (NEPA; 42 U.S.C. 
4321 et seq.), Clean Water Act (CWA), and MBTA) and endorsing Federal 
efforts to advance environmental goals. Water resources authorizations 
have also enhanced opportunities for USACE and other Federal agency 
involvement in studies and projects to specifically address objectives 
related to the restoration of ecological resources (e.g., section 1135 
of the Water Resources Development Act of 1986, as amended, 33 U.S.C. 
2201 et seq.) since the Interior least tern was listed.
    Executive Order (E.O.) 13186 (Responsibilities of Federal Agencies 
to Protect Migratory Birds; 66 FR 3853, January 17, 2001) requires all 
Federal agencies to use their authorities and conduct their actions to 
promote the conservation of migratory bird populations. Actions 
authorized by E.O. 13186 include: (1) Avoiding and minimizing adverse 
impacts to migratory birds; (2) habitat restoration and enhancement, 
and preventing pollution or detrimental alteration of migratory bird 
environments; (3) designing habitat and population conservation 
principles, measures, and practices into agency plans and planning 
processes; (4) promoting research and information exchange, including 
inventorying and monitoring; and (5) ensuring full consideration under 
NEPA of migratory birds such as the Interior least tern. These concepts 
have been incorporated by the USACE into its Environmental Operating 
Principles (Bridges et al. 2018, entire; USACE 2019, entire), and are 
being implemented within the jurisdictional waters inhabited by the 
Interior least tern. In the absence of the Act's protections, E.O. 
13186 and USACE operating principles and programs will continue to 
provide for protection and management of the Interior least tern and 
its habitats (see Habitat Criteria, above).
    The Civil Works Ecosystem Restoration Policy of 1999 (CWERP) (USACE 
ER 1165-2-501) identifies ecosystem restoration as one of the primary 
missions of the USACE Civil Works program. This policy requires a 
comprehensive examination of the problems contributing to ecosystem 
degradation, and the development of alternative means for their 
solution, with the intent of partially or fully reestablishing the 
attributes of a naturalistic, functioning, and self-regulating system.
    Implementation of actions authorized under E.O. 13186 and CWERP are 
discretionary, and contingent upon opportunity and annual 
appropriations and other budgetary constraints. However, many Federal 
action agencies now have an extensive history of managing and restoring 
Interior least tern habitats (some more than two decades) in compliance 
with non-discretionary requirements of section 7(a)(2) of the Act (in 
the Missouri, Red, Arkansas, and middle Mississippi Rivers), as well as 
discretionary components of section 7(a)(1) of the Act, E.O. 13186, and 
CWERP (in the Lower Mississippi River). As a result, many conservation 
measures have become standard operating practices (see Recovery 
Criteria, above).
    Interior least terns are listed as endangered in 16 of the 18 
States where they occur: Arkansas, Colorado, Illinois, Indiana, Iowa, 
Kansas, Kentucky, Louisiana, Mississippi, Missouri, Montana, Nebraska, 
New Mexico, South Dakota, Tennessee, and Texas. Many of the States 
noted above actively manage Interior least terns, including seasonal 
posting to prevent disturbance of nesting areas (e.g., Kentucky, 
Kansas); facilitating cooperative partnerships to protect and manage 
the bird (e.g., Nebraska, Indiana); developing State management plans 
for the Interior least tern (e.g., South Dakota; Aron 2005, entire); 
conducting site-specific research (e.g., Mississippi); and 
participating in multi-agency planning, management, and monitoring 
programs (e.g., Missouri River Recovery Implementation Committee).
    The removal of the species from Federal protection might prompt 
some States to remove the Interior least tern from their endangered 
species lists. Regardless of Federal status, most State laws protect 
native wildlife (including the Interior least tern) from take and 
require State permits, in addition to Federal permits, to collect, 
harm, or harass migratory bird species, such as the Interior least 
tern.
    Activities that may adversely affect the Interior least tern and/or 
its habitats will also continue to be subject to numerous regulatory 
mechanisms, including the MBTA, CWA, Fish and Wildlife Coordination Act 
(FWCA; 16 U.S.C. 661 et seq.), and NEPA. Federal actions to conserve 
and enhance Interior least tern habitats are now authorized by 
Executive Orders and Federal regulations enacted since the Interior 
least tern was listed in 1985. Additionally, post-delisting habitat 
management commitments by USACE encompass about 80 percent of the 
Interior least tern population (see Recovery Criteria, above). 
Therefore, we conclude that the existing regulatory mechanisms are 
adequate to protect the Interior least tern and address stressors to 
this species absent protections under the Act.

Effects of Climate Change

    The distributions of many terrestrial organisms, including birds, 
are shifting in latitude or elevation in response to climate warming 
(Chen et al. 2011, pp. 1024-1025). Although population declines, 
apparently in response to climate change effects, have been reported 
for long distance migrant bird species in both Europe and North 
America, the negative effects of climate change at one life or 
migratory stage may be compensated at another stage, e.g., by increased 
survival or reproduction on winter or breeding grounds (Knudson et al. 
2011, p. 9).
    The ability of migratory birds to cope with rapid climate change 
effects depends upon the rate of their adaptive response to the changes 
(Knudson et al. 2011, p. 12). Phenotypic plasticity (i.e., the ability 
to shift dates of migration, breeding, fledgling, etc.) may allow rapid 
adaptation to climate change effects in some species (Charmantier et 
al. 2008, entire). While there is little information available on 
Interior least tern phenology (life cycle events and how they are 
influenced by climate variation), their adaptations to habitats 
controlled by stochastic events, along with high mobility and use of 
anthropogenic habitats, indicate that they will be resilient to 
predicted effects of climate changes.
    Most climate change models predict increased extreme weather events 
(i.e., floods and droughts) throughout the Interior least tern's 
breeding range (Lubchenco and Karl 2012, pp. 33-36). In the absence of 
clear knowledge of Interior least tern wintering

[[Page 2574]]

distributions, potential effects of climate change on the bird when it 
is away from its breeding range are unknown. The Interior least tern is 
well adapted to cope with extreme hydrologic changes, and its habitat 
and productivity are closely tied with stochastic weather events. For 
example, while extreme floods may result in annual recruitment loss, 
such events are also the primary factor in creating, scouring, and 
maintaining high-quality sandbars where Interior least terns nest 
(Sidle et al. 1992, p. 134). On the other hand, extreme drought events 
that connect nesting islands to the mainland and result in increased 
predation of some Interior least tern colonies may be offset by higher 
abundance of available nesting areas, increased dispersal of 
reproductive efforts, and higher local recruitment rates of some 
colonies during low flow periods. Rooftop nesting birds are susceptible 
to catastrophic recruitment failure due to high summer temperatures 
(see Watterson 2009, pp. 23-24; Nupp and Petrick 2010, pp. 5-7), and 
colonies on natural habitats may also become negatively affected by 
increasing summer temperatures. However, Interior least terns are 
dispersed along a wide latitudinal and longitudinal gradient of climate 
conditions and are unlikely to experience rangewide catastrophic 
recruitment failure due to high summer temperatures. Therefore, while 
Interior least tern colonies may be locally or regionally affected by 
changes in frequency and duration of extreme flood events and droughts, 
or high temperatures, the dispersal of the Interior least tern over a 
wide geographical area encompassing a variety of latitudinal and 
longitudinal gradients, its long life, and its ability to move long 
distances indicate the tern's resilience to future patterns of 
predicted effects of climate change (Lott et al. 2013, p. 3623).

Habitat Loss and Fragmentation and the Effects of Climate Change

    Habitat destruction and fragmentation may reduce the likelihood of 
species surviving the effects of climate change, in part because 
smaller habitat patches sustain smaller populations (Hof et al. 2011, 
p. 2990). Habitat fragmentation can also impede the dispersal ability 
of species (Hof et al. 2011, pp. 2989-2990). While the Interior least 
tern has possibly been affected by loss of significant reaches of 
riverine habitat such as the lower Missouri River and lower Red River, 
it has also increased its longitudinal range by exploiting 
anthropogenic habitats such as reservoirs in central Texas, Colorado, 
and the Rio Grande, industrial sites in the Wabash River, and coal 
mines in Texas. Additionally, known population size has also increased 
by an order of magnitude since the range became fragmented, and genetic 
studies have demonstrated connectivity via gene flow within Interior 
least tern populations and between other least tern populations (i.e., 
California least tern and eastern least tern; Whittier et al. 2006, p. 
179).
    Invasive salt cedar and willow growth, decreases in annual 
rainfall, and overuse and depletion of aquifers, coupled with increased 
human water demands, are occurring in the Southern and Northern Plains 
rivers, possibly to the future detriment of Interior least tern habitat 
and forage availability in those drainages. However, increases in 
impervious surfaces (e.g., artificial structures or compacted soils 
associated with human developments) may offset the negative effects of 
climate change in some watersheds, while human demands such as urban or 
industrial use, and irrigation, could either offset or exacerbate 
climate change effects in others (Caldwell et al. 2012, p. 2854). Based 
on current data, the wide longitudinal and latitudinal distribution of 
the Interior least tern will likely offset any potential localized or 
regional reduction in habitat quantity or quality, at least in part, by 
new opportunities in other portions of its range.

Decline of Fish Prey

    Starvation of California least tern chicks has been reported due to 
the detrimental effects of El Ni[ntilde]o on fish abundance (Massey and 
Fancher 1989, p. 354; Massey et al. 1992, p. 980). Decreased fish prey 
availability has been locally linked to reduced Interior least tern egg 
weights, clutch size, and chick weights, and may have influenced chick 
survival and fledgling rates (Dugger 1997, pp. 94-95). Declines in fish 
prey have been noted on the Missouri River (Stucker 2012, p. 21) and in 
some years on the Mississippi River (Dugger 1997, pp. 113-114). Fish 
prey abundance has also been linked to cyclic river conditions (e.g., 
river stage during nesting season; Dugger 1997, p. 26). However, 
Interior least terns are strong flyers and capable of exploiting a 
large variety of aquatic habitats and fish species, including exotic 
species that may invade rivers such as Asian carp. These 
characteristics, coupled with the bird's long life, its ability to re-
nest, and its ability to relocate to more productive areas, enable it 
to cope with local periodic cycles of low fish prey abundance.

Other Factors

    Thompson et al. (1997, pp. 15-17) and others have documented the 
mortality of least tern eggs, chicks, and adults due to a number of 
additional factors, including flooding of nesting areas during heavy 
summer rains and high water events, exposure to pesticides and other 
contaminants (of coastal least tern; Jackson and Jackson 1985, p. 58), 
burial of eggs by sand, hailstorms, heat, cold, sand spurs (a common 
grass in this habitat with prickly burrs that stick to passing 
animals), fire ants, fireworks, airboats, off-road vehicles (ORVs), and 
human recreationists. Cattle trampling of Interior least tern eggs and 
chicks has been documented in the Red River (Hervey 2001, pp. 7-8). 
Nupp (2012, pp. 7-8) documented mortality of eggs and chicks from heat 
exposure in rooftop colonies.
    Sampling for contaminants in Interior least terns has been 
concentrated in the Missouri River drainage, where sub-lethal amounts 
of arsenic, mercury, chlorinated hydrocarbon, selenium, and 
polychlorinated biphenyl (PCBs) have been documented in individuals 
(Fannin and Esmoil 1993, pp. 153-157; Ruelle 1993, pp. 162-170; Allen 
et al. 1998, pp. 358-364); however, no incidences of death or decreased 
fitness of Interior least terns due to contaminants have been reported 
to date.
    ORV impacts have been documented in most drainages where Interior 
least terns nest (Red, Mississippi, Arkansas, Ohio, and Missouri River 
drainages). However, ORV access to nesting areas occurs only 
occasionally because it is usually limited to situations where low flow 
conditions allow such access. While other threats (i.e., sandstorms, 
hail storms, heat, cold, sand spurs, fire ants, fireworks, airboats, 
etc.) may increase in frequency and severity in some portions of the 
Interior least tern's range, most are site-specific and sporadic, or 
otherwise limited in scope.
    Interior least tern mortality occurs locally throughout the range 
due to a variety of natural or manmade factors. However, the wide 
distribution of the species, its current high numbers, its long life 
span, and its ability to relocate and re-nest make the Interior least 
tern resilient to occasional or periodic local sources of mortality, as 
well as potential effects of climate change. The increase in range and 
population size since 1985 indicates that sources of mortality to 
localized colonies are compensated by these traits of resiliency, as 
well as by the potential of high recruitment rates in

[[Page 2575]]

other Interior least tern colonies or populations.

Cumulative Effects

    Our analysis has identified no rangewide threats or stressors with 
significant effects to all breeding colonies or subpopulations. 
Monitoring data show some breeding colonies or subpopulation segments 
may decline or relocate due to localized stressors (e.g., predation, 
disturbance), regional stressors (e.g., droughts, floods), or their 
cumulative effects. Variations in colony locations, size, or 
subpopulation densities, however, are a characteristic of 
metapopulation dynamics, and have not been shown to threaten the 
rangewide status of the Interior least tern over an extended area. 
Additionally, the increases documented in the abundance and 
distribution of the Interior least tern, since it was listed in 1985, 
do not support a conclusion that any of these stressors cumulatively 
pose a threat to the Interior least tern.

Future Conditions and Species Viability

    Species viability, or its ability to survive long term, is related 
to its ability to withstand catastrophic population and species-level 
events (redundancy), to adapt to changing environmental conditions 
(representation), and to withstand disturbances of varying magnitude 
and duration (resiliency). The viability of a species is also dependent 
on the likelihood of new stressors or continued threats now and in the 
future that act to reduce a species' viability.
    Redundancy of populations is needed to provide a margin of safety 
for a species to withstand catastrophic events. Current information and 
observed trends since the species was listed in 1985 indicate that 
redundancy of the Interior least tern is currently ensured by the 
existence of hundreds of breeding colonies in multiple drainages across 
a wide latitudinal and longitudinal range (see Current Distribution and 
Abundance, above), and within a variety of natural and anthropogenic 
habitats (see Nesting Habitat and Behavior, above).
    Representation is the ability of a species to adapt to both near-
term and long-term changes in its physical (e.g., climate conditions, 
habitat conditions, and habitat structure) and biological (e.g., 
pathogens, competitors, and predators) environments. We can gauge 
representation by examining the breadth of genetic, phenotypic, and 
ecological diversity found within a species and its ability to disperse 
and colonize new areas. For the ILT, we evaluated representation across 
a breadth of historical ecological settings, and through preservation 
of the genetic diversity of the species. The Interior least tern was 
historically known from, and continues to occur in, two main natural 
habitat types: Large river sandbars and salt plains. While the salt 
plains populations were and continue to be historically localized in 
small portions of the Southern Plains, the sandbar populations occurred 
across a large latitudinal and longitudinal gradient, encompassing 
multiple river and stream orders, and a wide variety of climatic 
conditions. Little evidence of genetic structure has been found within 
the Interior least tern population (Draheim et al. 2010, p. 813), 
indicating high genetic connectivity between drainage subpopulations. 
There also appears to be high genetic connectivity between California, 
Interior, and eastern least terns (Draheim et al. 2010, p. 816). For 
these reasons, the Interior least tern appears to have adequate genetic 
and ecological representation to allow for adaptability to 
environmental changes.
    Resiliency allows a species to recover from periodic or occasional 
disturbance. Resilience of individual and mated terns is demonstrated 
by their ability to relocate and re-nest when habitat conditions 
deteriorate, or when disturbance by humans or predators becomes severe. 
Interior least tern metapopulation dynamics allow subpopulations and 
colonies to respond to changing habitat conditions, including their 
ability to exploit a variety of anthropogenic habitats that were not 
historically available (Lott et al. 2013, p. 3623). This resilience is 
augmented by the long life span and strong flight abilities of Interior 
least terns, and by the prospecting behavior (exploratory dispersal) of 
young birds across the landscape (Boyd and Thompson 1985, p. 405; Lott 
2012, p. 12; Shigeta in litt. 2014, entire).
    In addition to this review of redundancy, representation, and 
resiliency, which indicates a high likelihood of future viability for 
the Interior least tern, the Service worked with multiple partners to 
develop a habitat-driven, rangewide population model for the tern in 
order to consider status and population dynamics with and without 
continued management at local, regional, and rangewide scales (Iglay et 
al. 2012, entire; Lott and Sheppard 2017a, b, entire). The model, known 
as TernPOP (Lott and Sheppard 2017a, b, entire), applied simulation 
analyses that were designed to explore stakeholder-defined scenarios of 
potential future habitat change or changes in management. Fifty-five 
discrete scenarios spanned the geographic range of the Interior least 
tern and covered the topics of (1) sandbar nesting habitat loss, (2) 
habitat degradation, (3) changes in predator management programs, and 
(4) deliberate efforts to create mid-channel nesting sandbars for the 
tern. All 55 scenarios were evaluated relative to a ``No Action'' 
scenario. Thirty replicates of the model were run for 30 years, and 
population growth (or decline) rates were calculated for each replicate 
(and then averaged across replicates) at the spatial scales of scenario 
area, subpopulation, drainage population, and the entire listed 
population of the Interior least tern. Nearly all scenarios of regional 
management or habitat loss, even some viewed as implausible in the 
foreseeable future (e.g., loss of 50 percent of all sandbars on the 
Lower Mississippi River), had minimal effects on population growth 
rates calculated across the 30-year period at the spatial scales of 
subpopulation, population, and range (Lott and Sheppard 2017b, pp. 42-
61). In most cases, severe habitat degradation in even relatively large 
areas was insufficient to change the baseline population increases 
observed during ``No Action'' scenarios to population declines, beyond 
very local areas. Therefore, quantitative evaluation of population 
model outputs are similar to and support prior qualitative observations 
that Interior least tern populations are resilient to many potential 
changes in habitat conditions across their large river network (Lott et 
al. 2013, pp. 3622-3623; Lott and Sheppard 2017b, pp. 59-62).
    Based upon the analysis presented above, the Interior least tern 
cannot be considered to be conservation-reliant, because it has shown 
to be able to adapt to and exploit substantial habitat changes 
throughout its range. Although some (10 percent) local colonies and 
peripheral population segments of the Interior least tern may require 
management for long-term persistence, their success or failure within 
individual sites is not essential to the continued existence of the 
Interior least tern. Viability of the Interior least tern is assured by 
its resilience, representation, and redundancy throughout the remainder 
of its range. The Interior least tern will continue to be conserved by 
habitat management programs in more than 80 percent of its range (see 
Habitat Criteria under Recovery Criteria section, above).

Summary of Comments and Recommendations

    In our proposed rule published on October 24, 2019 (84 FR 56977), 
we requested that all interested parties

[[Page 2576]]

submit written comments on the proposal by December 23, 2019. We also 
requested public comments on the draft post-delisting monitoring (PDM) 
plan. We contacted appropriate Federal and State agencies, scientific 
experts and organizations, and other interested parties and invited 
them to comment on the proposal. A newspaper notice inviting general 
public comment across the range of the species was published in USA 
Today on October 28, 2019. We did not receive any requests for a public 
hearing.
    During the comment period, we received 25 letters or statements 
addressing the proposed action. These included comments from 2 peer 
reviewers, 4 State agencies in three States, 1 Federal agency, 1 
nongovernmental organization, and 17 individuals. All comments are 
posted at http://www.regulations.gov under Docket No. FWS-R4-ES-2018-
0082.
    In accordance with our policy, ``Notice of Interagency Cooperative 
Policy for Peer Review in Endangered Species Act Activities,'' which 
was published on July 1, 1994 (59 FR 34270) and our August 22, 2016, 
Director's Memorandum ``Peer Review Process,'', we solicited expert 
opinions from seven knowledgeable individuals with scientific expertise 
that included familiarity with this species, the geographic region in 
which it occurs, and conservation biology principles. We received 
responses from two peer reviewers.
    The peer reviewers expressed support for the proposed delisting and 
generally agreed with our analysis in the proposed rule. Both expressed 
concerns with our PDM plan, particularly the 5-year time period. Peer 
reviewer comments are addressed in the following summary and 
incorporated into the final rule as appropriate.
    We reviewed all comments for substantive issues and new information 
regarding the Interior least tern. Substantive comments we received 
during the comment period are addressed below and, where appropriate, 
are incorporated directly into this final rule. The majority of 
comments were related to the draft PDM plan and not the decision to 
delist the Interior least tern.

Peer Review Comments

    (1) Comment: Both peer reviewers and a nongovernmental organization 
commented that the Interior least tern population increase and the 
achievement of the recovery goal are partially attributable to improved 
and increased survey efforts. One of the peer reviewers suggested that 
the Interior least tern abundance data used at the time of listing were 
in error, and that should be considered as a reason for delisting.
    Our Response: The reported increase in rangewide numbers since the 
Interior least tern was listed is partially attributable to increased 
survey efforts over a wider geographical range and, in some areas, 
improved survey techniques. This conclusion was stated in our 2013 5-
year review of the Interior least tern (Service 2013) and in several 
places in our October 24, 2019, proposed delisting rule (84 FR 56977; 
see Population Trends under Species Information (p. 84 FR 56981) and 
Numerical Population Targets under Recovery (p. 84 FR 56982)). In 
addition, we also acknowledged the hypothesis that some proportion of 
the increase in rangewide least tern counts within the Interior Basin 
may be attributable to immigration of least terns from the Gulf Coast. 
We have retained these statements in those discussions in this final 
rule, and we have added an additional clarifying statement under 
Population Trends.
    When the Interior least tern was listed as endangered (50 FR 21784; 
May 28, 1985), we acknowledged the difficulty in assessing population 
size of a species with a widely scattered distribution and poorly known 
historical trends. At that time, the best available information, 
including multiple surveys conducted over the previous decade, 
indicated a significant decline in the range of the Interior least 
tern, low population numbers, low reproductive success, and significant 
threats to remnant breeding habitats. This conclusion was endorsed, and 
listing was supported by 13 State wildlife or conservation agencies 
within the range of the species. While the Interior least tern may have 
been more abundant and widespread than recognized at the time the 
species was listed, the best available scientific and commercial 
information supported our decision to list this species as endangered 
under the Act, and there is no evidence that the original data used at 
that time were in error.
    (2) Comment: One peer reviewer and a nongovernmental organization 
commented that the Service used limited and flawed information 
(Jorgensen 2009, entire; Farnsworth et al. 2017, entire) to minimize 
the importance of the Missouri and Platte Rivers in the recovery of the 
Interior least tern. They stated that the Service overlooked that both 
studies were conceptually and analytically problematic, and that 
editorials identifying key shortcomings were subsequently peer-reviewed 
and published in the same journals (Caitlan et al. 2010, entire; 
Alexander et al. 2018, entire). They expressed concern that the use of 
this information reverses the Service's decades-long position that 
naturally flowing and dynamic river systems are critically important to 
the Interior least tern, other listed species, and the ecosystems as a 
whole.
    Our Response: In our proposed delisting rule (84 FR 56977; October 
24, 2019) and this final rule, we have cited Jorgensen (2009, entire) 
and Farnsworth et al. (2017, entire), under Habitat Loss and 
Curtailment of Range, as examples that some anthropogenic activities 
are known to provide significant opportunities for Interior least tern 
nesting and recruitment, contributing to the population and range 
expansion of the species even within highly modified river systems. 
Neither of these commenters discounted the importance of anthropogenic 
habitats to tern recruitment in either the Platte or Missouri River.
    Farnsworth et al. (2017, entire) used historical hydrological and 
channel geometry data from a specific reach of the Platte River to 
suggest that the timing of seasonal flooding of low sandbars was not 
conducive to Interior least tern and piping plover recruitment success. 
This study also noted that anthropogenic habitats created by sand and 
gravel mines adjacent to the Platte River have been important in 
maintaining stable populations of these two birds within this system. 
Jorgensen (2009, entire) conducted a similar analysis for a short reach 
of the Missouri River in Sioux City, Iowa, concluding that off-site 
recruitment was important to tern and plover presence within this reach 
of the river. Caitlan et al. (2010, entire) and Alexander et al. (2018, 
entire) stated that the Jorgensen and Farnsworth et al. studies, 
respectively, were flawed and diminished the importance of natural 
river habitats to the ecology of the birds.
    When developing the proposed delisting rule, we were aware of the 
Caitlan et al. (2010, entire) and Alexander et al. (2018, entire) 
published editorials critiquing the Jorgensen and Farnsworth et al. 
studies. We were also aware that these critiques had been directly 
addressed by responses from the original authors clarifying semantic 
misinterpretations and including additional supporting information 
(Jorgensen 2010, entire; Farnsworth et al. 2018, entire). Both 
responses were accepted as closure of the identified issues within the 
same journals that the original articles and editorials were published.

[[Page 2577]]

    We have not used this information (Jorgensen 2009, entire; 
Farnsworth et al. 2017, entire) to discount or diminish the importance 
of natural riverine habitats to the tern or the ecosystem, but rather 
as supporting evidence of the resiliency of the Interior least tern 
relative to its ability to adapt to and exploit some anthropogenic 
changes to its habitats. Natural and anthropogenic habitats in both the 
Platte and Missouri Rivers continue to be important components of the 
greater Interior least tern metapopulation.
    (3) Comment: In their critique of the use of Farnsworth et al. 
(2017, entire) and Jorgensen (2009, entire), one peer reviewer and a 
nongovernmental organization stated that the Service did not consider 
the role of metapopulation dynamics in the use of anthropogenic 
habitats by Interior least terns in the Platte River. They noted that 
off-river anthropogenic habitats such as sand and gravel mines may not 
be sustainable and evolving mining practices may reduce the amount and 
quality of such habitats in the future.
    Our Response: Under Habitat Criteria and elsewhere in the proposed 
delisting rule (84 FR 56977; October 24, 2019) and this final rule, the 
Service discusses the role and importance of metapopulation dynamics in 
the current and future distribution and resilience of the Interior 
least tern. We find the information presented in the referenced studies 
is important to understanding the role of past and future habitat 
conditions in the Platte and Missouri Rivers to the metapopulation 
dynamics of the Interior least tern.
    Metapopulation dynamics allow species to exploit habitats that may 
change rapidly in abundance and/or quality and aid the re-establishment 
of extirpated populations. Both natural and anthropogenic least tern 
nesting habitats can be transitional in availability or quality. Some 
breeding colonies or subpopulation segments have declined or relocated 
due to localized stressors (e.g., predation, disturbance), regional 
stressors (e.g., droughts, floods), habitat changes (e.g., vegetation 
encroachment, reservoir management, mine closures), or their cumulative 
effects (Kirsch and Sidle 1999, p. 475; Service 2013, pp. 13-27). 
Resulting variations in tern colony locations, sizes, or subpopulation 
densities are a characteristic of metapopulation dynamics, and such 
declines have been offset by increases in other colonies or population 
segments (Lott and Sheppard 2017a, pp. 50-52). While future changes in 
mining practices within the Platte River drainage may affect their use 
by Interior least terns, metapopulation dynamics allow the birds to 
find and use other suitable habitats within or outside of the drainage 
for nesting.
    (4) Comment: One peer reviewer and a nongovernmental organization 
commented that the Service failed to reference or acknowledge changes 
to the Migratory Bird Treaty Act (MBTA) directed by the M-Opinion and 
encouraged the Service to evaluate the consequences relative to the 
Interior least tern.
    Our Response: After the publication of our October 24, 2019, 
proposed delisting rule, the Service published a proposed rule to adopt 
a regulation that defines the scope of the MBTA as it applies to 
conduct resulting in the injury or death of migratory birds protected 
by the MBTA (85 FR 5915; February 3, 2020). This proposed regulation, 
if made final, will define the scope of the MBTA's prohibitions to 
reach only actions directed at migratory birds, their nests, or their 
eggs, and take that is incidental to otherwise lawful activities would 
no longer be prohibited. This position is consistent with the 
Solicitor's Opinion M-37050, The Migratory Bird Treaty Act Does Not 
Prohibit Incidental Take, issued December 22, 2017. We have reviewed 
this information and have evaluated the potential effects of these 
proposed changes on the Interior least tern. Our analysis is presented 
above under Existing Regulatory Mechanisms. In summary, incidental take 
is not currently a primary threat to the rangewide status of the 
Interior least tern, but there is the potential that with removal of 
the protections of the Act and these proposed regulatory changes 
defining the scope of the MBTA, incidental take may increase in some 
nesting areas. However, as described above, should the proposed changes 
be adopted, BMPs and SOPs to avoid incidental take of the tern will 
continue to be implemented across more than 90 percent of the species' 
range (e.g., USACE 2013, entire; 2016, entire; 2017, entire; see 
Habitat Criteria, above). Therefore, the adoption of proposed 
regulatory changes to limit the scope of the take provisions of the 
MBTA are not likely to affect management commitments currently in 
place, which are expected to continue following delisting of the 
Interior least tern.
    (5) Comment: Both peer reviewers, along with the States of Oklahoma 
and Colorado, a nongovernmental conservation agency, and several other 
public commenters stated that the duration of PDM plan is inadequate 
and recommended modifying the duration to include monitoring every 
third year for a period of 15 years. They noted that the Interior least 
tern may have a lifespan of 15 to 20 years; therefore, limiting PDM to 
5 years may not be sufficient to track population fluctuations after 
delisting.
    Our Response: Following delisting, the Act requires us to 
effectively implement a monitoring system for a minimum of 5 years in 
cooperation with the States that are within the range of the Interior 
least tern. To fulfill the PDM requirement, we developed a draft PDM 
plan for the Interior least tern and coordinated review of the plan 
with the State agencies, USACE Districts and Divisions, other Federal 
agencies, and various nongovernmental organizations. We acknowledge 
that sustaining PDM efforts can be challenging and subject to competing 
priorities for available resources. Nonetheless, we designed the draft 
PDM plan that was realistic given limited resources. However, given the 
comments we received on the duration of the draft PDM plan, we will 
continue to work with our conservation partners to ensure development 
and implementation of an effective, final PDM plan, with an appropriate 
duration, for the Interior least tern.
    While section 4(g)(1) of the Act requires us to implement a system 
in cooperation with the States to effectively monitor the status of any 
species that have been recovered and removed from the List(s), it does 
not require the development of a formal PDM plan prior to removing the 
species from the List, or at any point. The Service and States have 
wide latitude in implementation of this provision. In the absence of a 
final PDM plan, monitoring, with surveys continuing in 2021, is 
expected to continue for more than 80 percent of the Interior least 
tern population due to management commitments by the USACE and the 
States. However, we generally desire to follow a written planning 
document to provide for the effective implementation of section 4(g), 
and we intend to do so here. We will notify the public of the final PDM 
plan on our website, https://www.fws.gov/mississippiES/, after 
coordination with our partners and when it becomes available.
    (6) Comment: One peer reviewer expressed concern that the potential 
of increased frequency and duration of flooding due to climate change 
was not addressed in the PDM plan. This peer reviewer also believes 
that there should be a mechanism in the plan for the Service to 
intervene if there are continued or recurrent flooding events.
    Our Response: The purpose of PDM is to track the post-delisting 
status of the Interior least tern to ensure that it remains secure from 
risk of extinction

[[Page 2578]]

following removal from the List. While the draft PDM plan does not 
identify a specific mechanism to intervene following flood events, it 
identifies actions that may be taken should monitoring indicate a 
substantial decline in the Interior least tern's population numbers or 
distribution. These actions include meeting with conservation partners, 
extending the monitoring period, modifying monitoring practices, 
initiating a rangewide status assessment, or relisting the Interior 
least tern, if warranted. As stated above under Our Response to (5) 
Comment, we will continue to work with our conservation partners to 
develop and implement an effective, final PDM plan for the Interior 
least tern that includes an appropriate duration and purpose to detect 
trends.
    (7) Comment: One peer reviewer asserted that in parts of the 
species' range some degree of human intervention will be needed for 
continued success and that an assessment of habitat management should 
be part of the PDM plan.
    Our Response: The Interior least tern's adaptation to, and 
exploitation of, anthropogenic habitats over the past several decades 
indicate that the species is no longer considered conservation-reliant 
and is recovered. However, we assessed the adequacy of habitat 
management commitments relative to recovery of the tern in our proposed 
delisting rule (84 FR 56977; October 24, 2019) and this final rule, 
finding that conservation actions and management by multiple 
conservation partners, most principally the USACE (e.g., USACE 2013, 
entire; 2016, entire; 2017, entire), will continue following delisting. 
Many conservation programs and commitments incorporate components of 
adaptive management, which provide for periodic assessment of habitat 
management actions relative to effects on the Interior least tern (see 
Habitat Criteria, above, under Recovery Criteria). As noted in the 
draft PDM and the proposed delisting rule, management commitments by 
USACE alone currently encompass about 80 percent of the Interior least 
tern breeding population, including large portions of the Mississippi, 
Red, Arkansas, and Missouri Rivers.
    As stated above under Our Response to (5) Comment, we will continue 
to work with our conservation partners to develop and implement an 
effective, final PDM plan for the Interior least tern that includes an 
appropriate duration and purpose to detect trends.
    (8) Comment: One peer reviewer expressed concerns that the 
inclusion of the Arkansas River as part of the Mississippi River 
subpopulation in the PDM plan dilutes the importance of the Arkansas 
River. This reviewer suggested subdividing the four major 
subpopulations to ensure that recovery is truly rangewide.
    Our Response: This comment refers to a map under ``Methods'' in the 
draft PDM plan showing the wide distribution of the tern, as well as 
the multiple habitats used as nesting areas. In the referenced map, 
Interior least tern subpopulations were defined by Lott et al. (2013, 
entire) based upon observed least tern dispersal movements relative to 
distance between nesting colonies. Based upon this analysis, the Lower 
Mississippi, Arkansas, Cimarron, and Canadian Rivers constitute one of 
four relatively continuous subpopulations. The identification of 
subpopulations does not reduce the importance of any geographical 
portion of a species' range, particularly as movement and population 
numbers relate to metapopulation dynamics. Additionally, the USACE 
Southwestern Division (SWD) Districts, who monitors the Arkansas River 
along with portions of the Red and Canadian Rivers, has committed to 
continue this monitoring post-delisting as appropriations allow.
    (9) Comment: One peer reviewer expressed concern that the PDM plan 
does not assess productivity of Interior least terns.
    Our Response: Within the Interior least tern metapopulation, 
measurements of productivity within individual colonies may be masked 
by movements between colonies or even drainages, depending upon habitat 
conditions. Attempts have been made to assess tern productivity at 
various locations (e.g., some Missouri River colony clusters, Platte 
River, Mississippi River sites, Wabash industrial sites); however, 
annual tern counts show little relation to previous year measurements 
of nest success, fledgling ratios, or annual recruitment. Therefore, we 
did not include assessment of Interior least tern productivity in the 
draft PDM plan.
    As noted in the draft PDM plan, rangewide PDM of the Interior least 
tern relies upon continuation of existing monitoring programs 
throughout the birds' extensive range. Monitoring methods have been, 
and will continue to be, at the discretion of each program, provided 
that they meet the minimum survey requirements in the PDM plan to 
record the location of breeding colonies (two or more birds) and make 
counts of adults present at the time the colonies are surveyed. Any 
additional efforts are at the discretion of the local program.
    (10) Comment: One peer reviewer characterized the PDM plan as 
providing a 10,000 bird ``population target'' and indicated such an 
approach appears to be arbitrary. The peer reviewer suggested that the 
Service might identify a percentage decline, as opposed to a specific 
number, to initiate further monitoring, or that the population model 
developed by the Service and the USACE (TernPOP) might be used to 
generate a target number based on chance of long-term persistence.
    Our Response: The 10,000 birds referenced in the draft PDM plan is 
not meant to be a population target, but rather, a threshold to review 
significance, methods, and potential threats with States and other 
collaborators before numbers might fall below the recovery objective 
(7,000 birds). Tern counts are not static or consistent, and there has 
always been high variability (15 percent or more) between annual counts 
at local, regional, and rangewide population levels over the period of 
record (35 years). Even so, the rangewide counts, as well as some 
subpopulations and colonies, have shown a general increasing trend over 
this same period.
    As we noted in the proposed delisting rule (84 FR 56977; October 
24, 2019) under Future Conditions and Species Viability, we developed 
TernPOP as a habitat-driven, rangewide population model to consider 
scenarios of status and population dynamics at multiple scales, with 
and without management, and with different scenarios of habitat loss. 
TernPOP is not designed to generate any target number based on long-
term persistence. Local and regional Interior least tern numbers and 
success are generally driven by habitat. Nearly all scenarios of 
regional management or habitat loss had minimal effects on population 
growth rates calculated across a 30-year period at the spatial scales 
of subpopulation, population, and range.
    (11) Comment: One peer reviewer expressed that the PDM plan should 
identify an action plan to quickly respond to any decline in numbers or 
productivity of the Interior least tern. The quick action plan should 
assess the causes of decline and direct resources for recovery.
    Our Response: Because we have a 35-year record of increase for the 
tern, the objective of the draft PDM plan is to ensure that populations 
of the species do not decline once the Act's protections have been 
removed. As noted under Our Response to (10) Comment, above, we 
identified a conservative rangewide count number to initiate inquiry 
with Federal, State, and other collaborators into whether

[[Page 2579]]

any observed decline in tern counts is real or an annual variation, 
and/or to investigate any potential causes of decline.

State Comments

    Section 4(b)(5)(A)(ii) of the Act states that the Secretary must 
give actual notice of a proposed regulation under section 4(a) to the 
State agency in each State in which the species is believed to occur 
and invite the comments of such agency. Section 4(i) of the Act directs 
that the Secretary will submit to the State agency a written 
justification for his or her failure to adopt regulations consistent 
with the agency's comments or petition. We solicited comments from the 
18 States within the summer breeding range of the Interior least tern. 
The States of Oklahoma, Colorado, and New Mexico responded with 
concurrence for the delisting action; however, the States of Oklahoma 
and Colorado expressed concern that the duration of PDM was inadequate 
to determine trends in this long-lived species (see Our Response to 
Comment (5), above).

Other Public Comments

    (12) Comment: One commenter observed that, while the Interior least 
tern may warrant delisting due to its population increase along the 
Mississippi River, its numbers have continued to decline in most other 
river systems within its range.
    Our Response: Annual changes in relative abundance of colonies or 
subpopulations of a metapopulation may fluctuate widely on an annual 
basis. In the proposed delisting rule (84 FR 56977; October 24, 2019), 
we presented information that most Interior least tern subpopulations 
have been stable or increasing over the past two decades. While the 
Mississippi River has experienced the greatest increase in Interior 
least tern nesting population size, the analysis of 15 river system 
subpopulations with 20 or more years of monitoring data indicates that 
over that period of record, 10 experienced increases, 4 remained 
relatively stable, and only 1 (below Ft. Peck Dam) experienced a 
significant decline.
    (13) Comment: Several commenters noted that the Interior least tern 
and its habitats remain vulnerable to climate change; one commenter was 
concerned about sea level rise and another stated that the species 
should remain threatened due to flooding associated with climate 
change.
    Our Response: Because the Interior least tern nests within the 
Interior Basin remote from coastal areas, inundation by sea level rise 
is not a concern to its breeding range. We considered other potential 
effects of climate change in the proposed delisting rule (84 FR 56977; 
October 24, 2019) and this final rule under Effects of Climate Change, 
including the potential of increased flooding frequency. We conclude 
that the wide range of the Interior least tern (16 degrees of 
longitude; 18 degrees of latitude), its metapopulation dynamics, and 
its ability to relocate and exploit a wide variety of habitats reduces 
the magnitude of such threats. The response of the Interior least tern 
to any specific flood event may not be readily observed, and while such 
events may suppress local or regional reproduction and recruitment in 
some years, or shift reproduction and recruitment to other areas, major 
flood events also reset habitats and may result in increased numbers of 
terns in subsequent years. For example, Missouri River flood years are 
generally followed by improved nesting habitats supporting large 
increases in tern numbers and recruitment in subsequent years.

Summary of Changes From the Proposed Rule

    We considered all comments and information we received during the 
comment period for the proposed rule to delist the Interior least tern 
(84 FR 56977; October 24, 2019). We made minor editorial changes 
throughout the rule and added additional information to clarify our 
understanding of ``foreseeable future,'' which published in an August 
27, 2019, final rule (84 FR 45020) (see 50 CFR 424.11(d)). These recent 
revisions did not significantly modify the Service's interpretation of 
foreseeable future, but rather, we codified a framework that sets forth 
how we will determine what constitutes the foreseeable future based on 
our long-standing practice. We have added a statement under Population 
Trends regarding the role of increased survey effort and the 
geographical extent of the area surveyed in the observed population 
increase since listing. Lastly, we also added information about how we 
considered the potential consequences to the Interior least tern of the 
February 3, 2020 (85 FR 5915), proposed rule to define the scope of the 
MBTA under Existing Regulatory Mechanisms, above.

Determination of Interior Least Tern Status

    Section 4 of the Act (16 U.S.C. 1533) and its implementing 
regulations (50 CFR part 424) set forth the procedures for determining 
whether a species meets the definition of ``endangered species'' or 
``threatened species.'' The Act defines endangered species as a species 
that is ``in danger of extinction throughout all or a significant 
portion of its range,'' and a threatened species as a species that is 
``likely to become an endangered species within the foreseeable future 
throughout all or a significant portion of its range.'' For a more 
detailed discussion on the factors considered when determining whether 
a species meets the definition of an endangered species or a threatened 
species and our analysis on how we determine the foreseeable future in 
making these decisions, please see Summary of Factors Affecting the 
Species.

Status Throughout All of Its Range

    Since its 1985 listing under the Act, the Interior least tern has 
shown an ability to adapt to changing environmental conditions caused 
by both human and natural disturbances. The Interior least tern nesting 
population encompasses hundreds of colonies in 18 States throughout the 
Interior Basin, from Montana southward through North Dakota, South 
Dakota, Nebraska, Colorado, Iowa, Kansas, Missouri, Illinois, Indiana, 
and Kentucky to eastern New Mexico, Oklahoma, Arkansas, Tennessee, 
Texas, Louisiana, and Mississippi (see supplemental documents at 
https://www.regulations.gov under Docket No. FWS-R4-ES-2018-0082). 
Therefore, the Interior least tern is highly redundant and resistant to 
future catastrophic events. Its representation is ensured by its 
continued occurrence within all known historical habitats (i.e., Salt 
Plains, multiple river and stream orders) across a large latitudinal 
and longitudinal gradient and a wide variety of climatic conditions. 
Interior least tern resilience is demonstrated by metapopulation 
dynamics, by its ability to adapt to multiple natural and anthropogenic 
conditions, and by evidence of high genetic connectivity between 
drainage subpopulations. Because the Interior least tern has been 
considered to be increasing and self-sustaining since listing (35 
years), and consists of a relatively large number of individuals with 
demonstrated high redundancy, representation, and resilience, we expect 
it to remain viable into the future.
    We have carefully assessed the best scientific and commercial 
information available regarding the threats faced by the Interior least 
tern. Our analysis found an increase in the abundance, number of 
breeding sites, and range of the Interior least tern; resiliency to 
existing and potential threats; active habitat management and the 
implementation of beneficial

[[Page 2580]]

management practices; and changes in existing regulatory mechanisms 
that are protective of migratory bird habitats. Known threats at the 
time of listing--habitat loss and curtailment of range, and predation--
have been reduced or adequately managed, and we have analyzed possible 
new threats related to climate change and determined that they are not 
significant threats to the Interior least tern now or within the 
foreseeable future. Existing State and Federal regulatory mechanisms 
are adequate to protect the tern. The net effect of current and 
predictable future stressors to the species, after considering 
applicable conservation measures and the existing regulatory 
mechanisms, are not sufficient to cause the Interior least tern to be 
in danger of extinction now or likely to become so within the 
foreseeable future throughout its range. We find that the Interior 
least tern has recovered so that it no longer meets the definition of 
an endangered species or a threatened species under the Act throughout 
its range.

Status Throughout a Significant Portion of Its Range

    Under the Act and our implementing regulations, a species may 
warrant listing if it is in danger of extinction or likely to become so 
in the foreseeable future throughout all or a significant portion of 
its range. Having determined that the Interior least tern is not in 
danger of extinction or likely to become so in the foreseeable future 
throughout all of its range, we now consider whether it may be in 
danger of extinction or likely to become so in the foreseeable future 
in a significant portion of its range--that is, whether there is any 
portion of the species' range for which it is true that both (1) the 
portion is significant; and (2) the species is in danger of extinction 
now or likely to become so in the foreseeable future in that portion. 
Depending on the case, it might be more efficient for us to address the 
``significance'' question or the ``status'' question first. We can 
choose to address either question first. Regardless of which question 
we address first, if we reach a negative answer with respect to the 
first question that we address, we do not need to evaluate the other 
question for that portion of the species' range.
    In undertaking this analysis for the Interior least tern, we chose 
to address the status question first--we considered information 
pertaining to the geographic distribution of both the species and the 
threats that the species faces to identify any portions of the range 
where the species is endangered or threatened. We considered whether 
any of the threats acting on the Interior least tern are geographically 
concentrated in any portion of the species' range at a biologically 
meaningful scale.
    We examined the following threats: Habitat loss, curtailment of 
range, predation, and inadequacy of regulatory mechanisms, including 
cumulative effects. We found that while some colonies may be locally 
affected by future threats, these threats are not geographically 
concentrated. This finding is supported by a habitat driven, rangewide 
population model (TernPOP; Lott and Sheppard 2017a, b, entire), which 
considered 55 discrete scenarios of potential future habitat change 
(threats) or changes in management at local, regional, and rangewide 
scales, and covered the topics of (1) sandbar nesting habitat loss, (2) 
habitat degradation, (3) changes in predator management programs, and 
(4) deliberate efforts to create mid-channel nesting sandbars for the 
tern (see Future Conditions and Species Viability, above). We found no 
concentration of threats in any portion of the Interior least tern's 
range at a biologically meaningful scale. Thus, there are no portions 
of the species' range where the species has a different status from its 
rangewide status. Therefore, no portions of the species' range provides 
a basis for determining that the species is in danger of extinction or 
likely to become an endangered species in the foreseeable future 
throughout a significant portion of its range. This approach is 
consistent with the courts' holdings in Desert Survivors v. Department 
of the Interior, No. 16-cv-01165-JCS, 2018 WL 4053447 (N.D. Cal. Aug. 
24, 2018), and Center for Biological Diversity v. Jewell, 248 F. Supp. 
3d, 946, 959 (D. Ariz. 2017).

Conclusion and Determination of Status

    Our review of the best available scientific and commercial 
information indicates that the Interior least tern is not in danger of 
extinction nor likely to become an endangered species within the 
foreseeable future throughout all or a significant portion of its 
range. Therefore, we find that the Interior least tern does not meet 
the definition of an endangered species or a threatened species under 
the Act.

Effects of This Rule

    This rule revises 50 CFR 17.11(h) by removing the Interior least 
tern from the Federal List of Endangered and Threatened Wildlife. On 
the effective date of this rule (see DATES, above), the protections 
provided by the Act, particularly through sections 7 and 9, no longer 
apply to the Interior least tern. Federal agencies are no longer 
required to consult with the Service under section 7 of the Act in the 
event that activities they authorize, fund, or carry out may affect the 
Interior least tern. There is no critical habitat designated for the 
Interior least tern; therefore, this rule does not affect 50 CFR 17.95. 
Removal of the Interior least tern from the List of Endangered and 
Threatened Wildlife does not affect the protection given to all 
migratory bird species under the MBTA.

Post-Delisting Monitoring

    Section 4(g)(1) of the Act requires us to monitor for not less than 
5 years, the status of all species that are delisted due to recovery. 
Post-delisting monitoring (PDM) refers to activities undertaken to 
verify that a species delisted due to recovery remains secure from the 
risk of extinction after the protections of the Act no longer apply. 
The primary goal of PDM is to monitor the species to ensure that its 
status does not deteriorate, and if a decline is detected, to take 
measures to halt the decline so that proposing it as endangered or 
threatened is not again needed. If at any time during the monitoring 
period, data indicate that protective status under the Act should be 
reinstated, we can initiate listing procedures, including, if 
appropriate, emergency listing under section 4(b)(7) of the Act. 
Section 4(g) of the Act explicitly requires us to cooperate with the 
States in development and implementation of PDM programs, but we remain 
responsible for compliance with section 4(g) of the Act and, therefore, 
must remain actively engaged in all phases of PDM. We also seek active 
participation of other entities that are expected to assume 
responsibilities for the species' conservation post-delisting. At the 
conclusion of the monitoring period, we will review all available 
information to determine if relisting, the continuation of monitoring, 
or the termination of monitoring is appropriate.

Draft Post-Delisting Monitoring Plan Overview

    While section 4(g)(1) of the Act requires us to implement a system 
in cooperation with the States to effectively monitor the status of any 
species that have been recovered and removed from the List(s), it does 
not require the development of a formal PDM plan prior to removing the 
species from the List, or at any point. The Service and States have 
wide latitude in implementation of this provision. However, we 
generally desire to follow a written planning document to provide for 
the effective implementation of section 4(g), and we intend to do so 
here. To fulfill the requirement to

[[Page 2581]]

monitor for not less than 5 years, we developed a draft PDM plan for 
the Interior least tern and coordinated review of the plan with the 
State agencies, USACE Districts and Divisions, other Federal agencies, 
and various nongovernmental organizations. We published a notice of 
availability of a draft PDM plan with the proposed delisting rule (84 
FR 56977; October 24, 2019). However, given the comments we received on 
the duration of the draft PDM plan, we will continue to work with our 
conservation partners to develop and implement an effective, final PDM 
plan, with an appropriate duration, for Interior least tern. Existing 
monitoring programs over more than 80 percent of the species' range 
(e.g., USACE 2013, 2016, 2018) are committed to continue monitoring 
following delisting as we coordinate planning, and in the absence of a 
final PDM plan, periodic monitoring, with surveys in 2021, is expected 
to continue into the indefinite future due to management commitments by 
the USACE and the States, regardless of the tern's status under the 
Act. However, we generally desire to follow a written planning document 
to provide for the effective implementation of section 4(g), and we 
intend to do so here. We will notify the public of the final PDM plan 
on our website, https://www.fws.gov/mississippiES/, after coordination 
with our partners and when it becomes available. The current draft PDM 
plan is available at https://www.fws.gov/mississippiES/.

Required Determinations

National Environmental Policy Act

    We have determined that environmental assessments and environmental 
impact statements, as defined under the authority of the National 
Environmental Policy Act (NEPA; 42 U.S.C. 4321 et seq.), need not be 
prepared in connection with determining and implementing a species' 
listing status under the Endangered Species Act. We published a notice 
outlining our reasons for this determination in the Federal Register on 
October 25, 1983 (48 FR 49244).

Government-to-Government Relationship With Tribes

    In accordance with the President's memorandum of April 29, 1994 
(Government-to-Government Relations with Native American Tribal 
Governments; 59 FR 22951), Executive Order 13175 (Consultation and 
Coordination with Indian Tribal Governments), and the Department of the 
Interior's manual at 512 DM 2, we readily acknowledge our 
responsibility to communicate meaningfully with recognized Federal 
Tribes on a government-to-government basis. In accordance with 
Secretarial Order 3206 of June 5, 1997 (American Indian Tribal Rights, 
Federal-Tribal Trust Responsibilities, and the Endangered Species Act), 
we readily acknowledge our responsibilities to work directly with 
Tribes in developing programs for healthy ecosystems, to acknowledge 
that Tribal lands are not subject to the same controls as Federal 
public lands, to remain sensitive to Indian culture, and to make 
information available to Tribes.
    We do not believe that any Tribes will be affected by this rule. 
However, we contacted each of the Tribes within the range of the 
Interior least tern and requested their input on the proposed delisting 
rule and draft PDM. We did not receive any comments from them.

References Cited

    A complete list of references cited is available on http://www.regulations.gov under Docket Number FWS-R4-ES-2018-0082, or upon 
request from the Field Supervisor, Mississippi Ecological Services 
Field Office (see FOR FURTHER INFORMATION CONTACT).

Author

    The primary author of this rule is Paul Hartfield, Mississippi 
Ecological Services Field Office (see FOR FURTHER INFORMATION CONTACT).

List of Subjects in 50 CFR Part 17

    Endangered and threatened species, Exports, Imports, Reporting and 
recordkeeping requirements, Transportation.

Regulation Promulgation

    Accordingly, we amend part 17, subchapter B of chapter I, title 50 
of the Code of Federal Regulations, as set forth below:

PART 17--ENDANGERED AND THREATENED WILDLIFE AND PLANTS

0
1. The authority citation for part 17 continues to read as follows:

    Authority:  16 U.S.C. 1361-1407; 1531-1544; 4201-4245, unless 
otherwise noted.


Sec.  17.11  [Amended]

0
2. Amend Sec.  17.11(h) by removing the entry for ``Tern, least 
[Interior DPS]'' under ``Birds'' from the List of Endangered and 
Threatened Wildlife.

Signing Authority

    The Director, U.S. Fish and Wildlife Service, approved this 
document and authorized the undersigned to sign and submit the document 
to the Office of the Federal Register for publication electronically as 
an official document of the U.S. Fish and Wildlife Service. Aurelia 
Skipwith, Director, U.S. Fish and Wildlife Service, approved this 
document on November 19, 2020, for publication.

    Dated: November 19, 2020.
Madonna Baucum,
Regulations and Policy Chief, Division of Policy, Economics, Risk 
Management, and Analytics, Joint Administrative Operations, U.S. Fish 
and Wildlife Service.
[FR Doc. 2020-28192 Filed 1-12-21; 8:45 am]
BILLING CODE 4333-15-P