Endangered and Threatened Wildlife and Plants; Removal of the Interior Least Tern From the Federal List of Endangered and Threatened Wildlife, 56977-56991 [2019-23119]

Agencies

• Fish and Wildlife Service
• DEPARTMENT OF THE INTERIOR

[Federal Register Volume 84, Number 206 (Thursday, October 24, 2019)]
[Proposed Rules]
[Pages 56977-56991]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2019-23119]


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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[Docket No. FWS-R4-ES-2018-0082; FXES11130900000-178-FF0932000]
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: Proposed rule.

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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), propose to 
remove the inland population of the least tern (Interior least tern) 
(Sterna (now Sternula) antillarum), from the Federal List of Endangered 
and Threatened Wildlife. The Interior least tern is a bird that nests 
adjacent to major rivers of the Great Plains and Lower Mississippi 
Valley. This proposed action is based on a thorough review of the best 
available scientific and commercial data, which indicate that the 
Interior least tern has recovered and no longer meets the definition of 
an endangered or a threatened species under the Endangered Species Act 
of 1973, as amended (Act). Our review shows that threats identified for 
the species at the time of listing, i.e., habitat loss, curtailment of 
range, predation, and inadequacy of regulatory mechanisms, have been 
eliminated or reduced, and the Interior least tern has increased in 
abundance and range. We also announce the availability of a draft post-
delisting monitoring (PDM) plan for the Interior least tern. We seek 
information, data, and comments from the public regarding this proposed 
rule and the associated draft PDM plan.

DATES: We will accept comments received or postmarked on or before 
December 23, 2019. Comments submitted electronically using the Federal 
eRulemaking Portal (see ADDRESSES, below) must be received by 11:59 
p.m. Eastern Time on the closing date. We must receive requests for 
public hearings, in writing, at the address shown in FOR FURTHER 
INFORMATION CONTACT by December 9, 2019.

ADDRESSES: Written comments: You may submit comments on this proposed 
rule and the associated draft PDM plan by one of the following methods:
    (1) Electronically: Go to the Federal eRulemaking Portal: https://www.regulations.gov. In the Search box, enter FWS-R4-ES-2018-0082, 
which is the docket number for this rulemaking. Then, click on the 
Search button. On the resulting page, in the Search panel on the left 
side of the screen, under the Document Type heading, click on the 
Proposed Rule box to locate this document. You may submit a comment by 
clicking on ``Comment Now!''
    (2) By hard copy: Submit by U.S. mail or hand-delivery to: Public 
Comments Processing, Attn: FWS-R4-ES-2018-0082, U.S. Fish and Wildlife 
Service, MS: BPHC, 5275 Leesburg Pike, Falls Church, VA 22041-3803.
    We request that you send comments only by the methods described 
above. We will post all comments on https://www.regulations.gov. This 
generally means that we will post any personal information you provide 
us (see Public Comments, below, for more information).
    Document availability: The proposed rule, draft PDM plan, and 
supporting documents are available at https://www.regulations.gov under 
Docket No. FWS-R4-ES-2018-0082.

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, we are required to 
conduct a review of all listed species at least once every 5 years (5-
year review) to review their status and determine whether they should 
be classified differently or removed from listed status. In the Act, 
the term ``species'' includes ``any subspecies of fish or wildlife or 
plants, and any distinct population segment [DPS] of any species of 
vertebrate fish or wildlife which interbreeds when mature.'' Therefore, 
we use the term ``species'' to refer to the Interior population of the 
least tern in this proposed rule. In our 2013 5-year review for the 
Interior least tern, we recommended removing the Interior least tern 
from the List of Endangered and Threatened Wildlife (i.e., 
``delisting'' the species). However, to change the status of a listed 
species under the Act, we must complete the formal rulemaking process. 
Therefore, we are publishing this proposed rule in the Federal Register 
and seeking public comments on it. Within 1 year of the publication of 
this proposed rule, we will make a final determination on the proposal.
    What this document does. This document proposes to delist the 
Interior least tern (Sterna (now Sternula) antillarum).
    The basis for our action. Under the Act, we may delist a species if 
the best scientific and commercial data indicate

[[Page 56978]]

the species is neither an endangered species nor a threatened species 
for one or more of the following reasons:
    (1) The species is extinct;
    (2) The species has recovered and is no longer endangered or 
threatened; or
    (3) The original data used at the time the species was classified 
were in error. Here, we have determined that the Interior least tern 
may be considered for delisting based on recovery. Our review of the 
status of and listing factors for the Interior least tern indicated (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 
birds such as the Interior least tern. Accordingly, the Interior least 
tern no longer meets the definition of an endangered or threatened 
species under the Act.
    Peer review. We are requesting comments from independent 
specialists to ensure that we base our determination on scientifically 
sound data, assumptions, and analyses.

Information Requested

Public Comments

    We want any final rule resulting from this proposal to be as 
accurate and effective as possible. Therefore, we invite tribal and 
governmental agencies, the scientific community, industry, and other 
interested parties to submit data, comments, and new information 
concerning this proposed rule. The comments that will be most useful 
and likely to influence our decision are those that are supported by 
data or peer-reviewed studies and those that include citations to, and 
analyses of, applicable laws and regulations. Please make your comments 
as specific as possible and explain the basis for them. In addition, 
please include sufficient information with your comments to allow us to 
authenticate any scientific or commercial data you reference or 
provide. In particular, we are seeking comments on:
    (1) Biological data regarding the Interior least tern, including 
the locations of any additional populations, survey data, or other 
relevant information;
    (2) Relevant data concerning any threats (or lack thereof) to the 
Interior least tern;
    (3) Additional information regarding the range, distribution, life 
history, ecology, and habitat use of the Interior least tern;
    (4) Current or planned activities within the geographic range of 
the Interior least tern that may negatively impact or benefit the 
Interior least tern; and
    (5) The draft PDM plan and the methods and approach detailed in it, 
including, but not limited to: (a) The duration of the monitoring 
period; (b) the survey and monitoring approach; (c) the triggers 
identified to detect change; and (d) the length of time to extend PDM 
if change is detected.
    Please note that submissions merely stating support for or 
opposition to the action under consideration without providing 
supporting information, although noted, will not be considered in 
making a determination, as section 4(b)(1)(A) of the Act (16 U.S.C. 
1531 et seq.) directs that determinations as to whether any species is 
an endangered or threatened species must be made ``solely on the basis 
of the best scientific and commercial data available.''
    In developing a final determination on this proposed action, we 
will take into consideration all comments and any additional 
information we receive. Such information may lead to a final rule that 
differs from this proposal. All comments and recommendations, including 
names and addresses, will become part of the administrative record.
    You may submit your comments and materials concerning the proposed 
rule by one of the methods listed in ADDRESSES. We request that you 
send comments only by the methods described in ADDRESSES.
    We will post your entire comment--including your personal 
identifying information--on https://www.regulations.gov. If you provide 
personal identifying information in your comment, you may request at 
the top of your document that we withhold this information from public 
review. However, we cannot guarantee that we will be able to do so.
    Comments and materials we receive, as well as supporting 
documentation we used in preparing this proposed rule, will be 
available for public inspection on https://www.regulations.gov.

Public Hearing

    Section 4(b)(5)(E) of the Act provides for a public hearing on this 
proposal, if requested. We must receive requests for a public hearing, 
in writing, at the address shown in FOR FURTHER INFORMATION CONTACT by 
the date shown in DATES. We will schedule a public hearing on this 
proposal, if requested, and announce the date, time, and place of the 
hearing, as well as how to obtain reasonable accommodations, in the 
Federal Register at least 15 days before the hearing.

Peer Review

    In accordance with our policy published in the Federal Register on 
July 1, 1994 (59 FR 34270), and the OMB's Final Information Quality 
Bulletin for Peer Review, dated December 16, 2004, we will solicit the 
expert opinions of at least three appropriate and independent 
specialists regarding the science in this proposed rule and the draft 
PDM plan. The purpose of such review is to ensure that we base our 
decisions on scientifically sound data, assumptions, and analyses. The 
peer reviewers have expertise in the Interior least tern's biology, 
habitat, and physical or biological factors that will inform our 
determination. We will send peer reviewers copies of this proposed rule 
and the draft PDM plan immediately following publication of this 
proposed rule in the Federal Register. We will invite them to comment, 
during the public comment period, on the specific assumptions and 
conclusions regarding this proposed delisting rule and the associated 
draft PDM plan. We will summarize the opinions of these reviewers in 
the final decision documents, and we will consider their input and any 
additional information we receive as part of our process of making a 
final decision on this proposal and draft PDM plan. Such communication 
may lead to a final decision that differs from this proposal.

Previous Federal Actions

    On May 28, 1985, we published a final rule in the Federal Register 
(50 FR 21784) listing the Interior least tern as endangered, due to the 
low numbers and scattered distribution of the tern and to threats to 
the bird's breeding habitat. The listed population included only those 
least terns that breed and nest within the boundary of the continental 
United States on interior rivers and other water bodies. On October 19, 
1990, we released a recovery plan for the Interior population of the 
least tern (Service 1990). In 1991, we announced in the Federal 
Register (56 FR 56882; November 6, 1991) a 5-year review of all 
endangered and threatened species listed before January 1, 1991, under 
the Act, including the Interior least tern. No change in the bird's 
listing classification was found appropriate as a result of that 5-year 
review.
    We completed another 5-year review for the Interior least tern on 
October 24, 2013, and posted it on the Service's website. This 5-year 
review summarized all new information accumulated on the Interior least 
tern since 1991, and recommended delisting due to recovery.

[[Page 56979]]

This 5-year review is a supplemental document to the proposed rule and 
is provided at https://www.regulations.gov under Docket No. FWS-R4-ES-
2018-0082 or https://www.fws.gov/mississippiES/.
    For additional details on previous Federal actions, including 
recovery actions, see discussion under Recovery, below.

Species Information

    A thorough review of the taxonomy, life history, ecology, and 
overall viability of the Interior least tern was presented in the 5-
year review (Service 2013). Below, we present a summary of the 
biological and distributional information discussed in the 5-year 
review and new information published or obtained since.

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 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). Data indicate that 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 population 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). 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 
underutilized 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

[[Page 56980]]

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).

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, see p. 50 FR 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). 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; Downing 1980; Ducey 
1981) 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

[[Page 56981]]

(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 
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.
    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

    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 are not 
regulatory documents and are instead intended to: (1) Establish goals 
for long-term conservation of a listed species; (2) define criteria 
that are designed to indicate when the threats facing a species have 
been removed or reduced to such an extent that the species may no 
longer need the protections of the Act; and (3) provide guidance to our 
Federal, State, and other governmental and nongovernmental partners on 
methods to minimize threats to listed species. There are many paths to 
accomplishing recovery of a species, and recovery may be achieved 
without all criteria being fully met. For example, one or more criteria 
may have been exceeded while other criteria may not have been 
accomplished, yet the Service may judge that, overall, the threats have 
been minimized sufficiently, and the species is robust enough, to 
reclassify the species from endangered to threatened (i.e., to 
``downlist'' the species) or perhaps to delist the species. In other 
cases, recovery opportunities may have been recognized that were not 
known at the time the recovery plan was finalized. These opportunities 
may be used instead of methods identified in the recovery plan.
    Likewise, information on the species may be learned that was not 
known at the time the recovery plan was finalized. The new information 
may change the extent that criteria need to be met for recognizing 
recovery of the species. In short, recovery of a species is a dynamic 
process requiring adaptive management that may, or may not, fully 
follow 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 is to meet the standard of recovery that leads to 
delisting the Interior least tern. Recovery plans provide a road map 
for the public with site-specific management actions for private, 
Tribal, federal, and state cooperation in conserving listed species and 
their ecosystems. A recovery plan provides guidance on how best to help 
listed species achieve recovery. 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 summarized within the 5-year review and 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). 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

[[Page 56982]]

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 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 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 
2019a), particularly in comparison to other drainages that have 
experienced increases in tern populations. Based on the lack of 
increase, 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. Monitoring data 
show that 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 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 Kansas 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 2017, 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 to 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 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

[[Page 56983]]

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 
habitats have been incorporated into USACE river management programs as 
standard operating procedures (SOPs) or Best Management Practices 
(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, 2016, 2017) are protective of 
waters and habitats managed by USACE that support about 80 percent of 
the Interior least tern's range. 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 Shepard 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 29 years without protections achieved 
through such acquisition or easements. Although some Interior least 
tern nesting colonies occur on protected public lands such as wildlife 
refuges, they represent only a small portion (less than 2 percent) of 
the range-wide 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, 2016, 2017).
    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)). 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). This program, initiated in 1997, also targets management needs 
of endangered pallid sturgeon and whooping crane, and the threatened 
piping plover. 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, as well as 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 and 2011, by Duke Energy Corporation (Hayes 
and Pike 2011, entire). The Indiana

[[Page 56984]]

Nongame and Endangered Wildlife Program continues to coordinate 
conservation and monitoring efforts on industrial and river sites along 
the Wabash River by Duke Energy, Service, and other Indiana Department 
of Natural Resources personnel (Mills 2018, p. 14). Since the Interior 
least tern is protected by the State of Indiana, management and 
monitoring is expected to continue 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 conservation (sections 6, 
7(a)(1), and 10) or consultation (section 7(a)(2)) requirements of the 
Act. 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 should the tern be delisted; however, it is also likely that 
the terns 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 metapopulaion, 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 and is recovered. 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 range-wide, 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, 2016, 2017). 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. Therefore, we believe the recovery of the Interior least 
tern has been fully achieved.

Summary of Factors Affecting the Species

    Section 4 of the Act and its implementing regulations (50 CFR part 
424) set forth the procedures for listing species, reclassifying 
species, or removing species from listed status. We may determine that 
a species is an endangered or threatened species due to one or more of 
the five factors described in section 4(a)(1) of the Act: (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.
    A recovered species is one that no longer meets the Act's 
definition of endangered species or threatened species. Determining 
whether the status of a species has improved to the point that it can 
be delisted or downlisted requires consideration of the same five 
factors identified above. 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). We may delist a species according to 
50 CFR 424.11(d) if the best available scientific and commercial data 
indicate that the species is neither endangered nor threatened for the 
following reasons: (1) The species is extinct; (2) the species has 
recovered and is no longer endangered or threatened; and/or (3) the 
original scientific data used at the time the species was classified 
were in error. 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 any other 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 
May 28, 1985, listing rule (50 FR 21784) 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) (Service 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.

[[Page 56985]]

    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 addition 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 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 (Factor E), 
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) (Aron in 
litt. 2012). 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.

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 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 high flow events 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

[[Page 56986]]

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 discharge 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 Related to Effects of Climate Change

    Hof et al. (2011, p. 2990) noted that 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. 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, and industrial sites in the 
Wabash. 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 
(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 utilization, 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., sand 
storms, 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 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

[[Page 56987]]

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' redundancy, representation, and 
resiliency.
    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).
    Adequate representation ensures that the species' adaptive 
capabilities are conserved, specifically through its representation 
across all 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 tern will continue to be conserved by habitat management 
programs over more than 80 percent of its range (see Habitat Criteria 
under Recovery section, above).

[[Page 56988]]

Inadequacy of 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 of the Interior (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.
    When the Interior least tern was listed in 1985, the listing rule 
(50 FR 21784) noted that while the MBTA protected migratory birds from 
harm or harassment, it did not provide a mechanism to address habitat 
threats. It concluded, therefore, in the absence of protection under 
the Endangered Species 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 above, 
however, the effects of channel engineering on the species may have 
been more beneficial than detrimental, at least in 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 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. Recent 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.).
    Executive Order (E.O.) 13186 (Responsibilities of Federal Agencies 
to Protect Migratory Birds; 66 FR 3853), enacted in 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 (USACE 2019b and 2019c), 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, 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, 
above).
    Interior least terns are listed as endangered in the following 16 
of the 18 States where they occur: South Dakota, Nebraska, Colorado, 
Iowa, Illinois, Missouri, Kansas, Mississippi, Arkansas, Louisiana, 
Kentucky, Tennessee, Indiana, New Mexico, Montana, 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); 
conducting site-specific research (e.g., Mississippi); and 
participating in multi-agency planning, management, and monitoring 
programs (e.g., Missouri River Recovery Implementation Committee).
    Interior least tern protection under State laws may continue 
following Federal delisting. This proposed rule, if made final, might 
prompt some to several States to follow the final federal delisting 
determination and remove the Interior least tern from their endangered 
species lists, but in other States, the tern may continue to meet the 
definition of State endangered. Regardless of Federal laws, 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 
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

[[Page 56989]]

Recovery, 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.

Proposed Determination

    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, 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 (34 
years), and consists of a relatively large number of individuals with 
demonstrated high redundancy, representation, and resilience, we expect 
it to persist into the future.
    We have carefully assessed the best scientific and commercial 
information available regarding the threats faced by the Interior least 
tern in developing this proposed rule. 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 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 (Factor A) and predation 
(Factor C)--have been reduced or adequately managed, and we have 
analyzed possible new threats (Factor E) and determined that they are 
not significant threats to the Interior least tern. Existing State and 
Federal regulatory mechanisms (Factor D) are adequate to protect the 
tern from the reduced threats. 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 meet 
the definition of an endangered or threatened species. 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.

Determination of 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 (SPR). Where the best available information allows the 
Services to determine a status for the species rangewide, that 
determination should be given conclusive weight because a rangewide 
determination of status more accurately reflects the species' degree of 
imperilment and better promotes the purposes of the Act. Under this 
reading, we should first consider whether the species warrants listing 
``throughout all'' of its range and proceed to conduct a ``significant 
portion of its range'' analysis if, and only if, a species does not 
qualify for listing as either an endangered or a threatened species 
according to the ``throughout all'' language.
    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 an SPR. 
The range of a species can theoretically be divided into portions in an 
infinite number of ways, so we first screen the potential portions of 
the species' range to determine if there are any portions that warrant 
further consideration. To do the ``screening'' analysis, we ask whether 
there are portions of the species' range for which there is substantial 
information indicating that: (1) The portion may be significant; and, 
(2) the species may be, in that portion, either in danger of extinction 
or likely to become so in the foreseeable future. For a particular 
portion, if we cannot answer both questions in the affirmative, then 
that portion does not warrant further consideration and the species 
does not warrant listing because of its status in that portion of its 
range. We emphasize that answering these questions in the affirmative 
is not a determination that the species is in danger of extinction or 
likely to become so in the foreseeable future throughout a significant 
portion of its range--rather, it is a step in determining whether a 
more detailed analysis of the issue is required.
    If we answer these questions in the affirmative, we then conduct a 
more thorough analysis to determine whether the portion does indeed 
meet both of the SPR prongs: (1) The portion is significant and (2) the 
species is, in that portion, either in danger of extinction or likely 
to become so in the foreseeable future. Confirmation that a portion 
does indeed meet one of these prongs does not create a presumption, 
prejudgment, or other determination as to whether the species is an 
endangered species or threatened species. Rather, we must then 
undertake a more detailed analysis of the other prong to make that 
determination. Only if the portion does indeed meet both SPR prongs 
would the species warrant listing because of its status in a 
significant portion of its range.
    At both stages in this process--the stage of screening potential 
portions to identify any portions that warrant further consideration 
and the stage of undertaking the more detailed analysis of any portions 
that do warrant further consideration--it might be more efficient for 
us to address the ``significance'' question or the ``status'' question 
first. Our selection of which question to address first for a 
particular portion depends on the biology of the species, its range, 
and the threats it faces. 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 second question for 
that portion of the species' range.
    For the Interior least tern, we chose to evaluate the status 
question (i.e., identifying portions where the Interior least tern may 
be in danger of extinction or likely to become so in the foreseeable 
future) first. To conduct this screening, we considered whether the 
threats are geographically concentrated in any portion of the species' 
range at a biologically meaningful scale. If a species is not in danger 
of extinction or likely to become so in the foreseeable future 
throughout all of its range and the threats to the species are 
essentially uniform throughout its range, then the species would not 
have a greater level of imperilment in any portion of its range than it 
does throughout all of its

[[Page 56990]]

range and therefore no portions would qualify as an SPR.
    We examined the following threats: Habitat loss, curtailment of 
range, predation, and inadequacy of regulatory mechanisms, including 
cumulative effects. We found no concentration of threats in any portion 
of the Interior least terns range at a biologically meaningful scale. 
Since we found no portions of the species' range where threats are 
significantly concentrated or substantially greater than in other 
portions of its range, we did not identify any portions where the 
species may be in danger of extinction or likely to become so in the 
foreseeable future. Therefore, no portions warrant further 
consideration through a more detailed analysis, and the species is not 
in danger of extinction or likely to become so in the foreseeable 
future in any significant portion of its range. Our approach to 
analyzing SPR in this determination is consistent with the court's 
holding in Desert Survivors v. Department of the Interior, No. 16-cv-
01165-JCS, 2018 WL 4053447 (N.D. Cal. Aug. 24, 2018).
    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.

Conclusion

    We have determined that none of the existing or potential threats, 
either alone or in combination with others, is likely to cause the 
Interior least tern to be in danger of extinction throughout all or a 
significant portion of its range, nor is any likely to cause the 
species to become an endangered species within the foreseeable future 
throughout all or a significant portion of its range. On the basis of 
our evaluation, we conclude that, due to recovery, the Interior least 
tern is not an endangered or a threatened species. We therefore propose 
to remove the Interior least tern from the Federal List of Endangered 
and Threatened Wildlife at 50 CFR 17.11(h).

Effects of This Proposed Rule

    If we adopt this rule as proposed, the prohibitions and 
conservation measures provided by the Act would no longer apply to the 
Interior least tern. Federal agencies would no longer be required to 
consult with us under section 7 of the Act to ensure that any action 
authorized, funded, or carried out by them is not likely to jeopardize 
the Interior least tern's continued existence. The provisions of the 
MBTA will remain in place. The MBTA protects the bird and its parts, 
nests, and eggs from taking and trade; and Federal permits are required 
for certain actions like scientific collecting and relocation (see 
Inadequacy of Existing Regulatory Mechanisms, above).
    If adopted, this rule would not affect the Interior least tern's 
status as an endangered or threatened species under State laws or 
suspend any other legal protections provided by State law. States may 
have more restrictive laws protecting wildlife, and these will not be 
affected by this Federal action. However, this proposed rule, if made 
final, may prompt some States to remove protection for the Interior 
least tern under their State endangered species laws.

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. 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.
    Section 4(g) of the Act explicitly requires that we cooperate with 
the States in development and implementation of PDM programs. However, 
we remain ultimately responsible for compliance with section 4(g) 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 after delisting.
    We have prepared a draft PDM plan for the Interior least tern 
(Service 2017). The draft plan:
    (1) Summarizes the Interior least tern's status at the time of 
delisting;
    (2) Defines thresholds or triggers for potential monitoring 
outcomes and conclusions;
    (3) Lays out frequency and duration of monitoring;
    (4) Articulates monitoring methods, including sampling 
considerations;
    (5) Outlines data compilation and reporting procedures and 
responsibilities; and
    (6) Proposes a PDM implementation schedule, including timing and 
responsible parties.
    The draft PDM plan is availability for public review at https://www.regulations.gov under Docket Number FWS-R4-ES-2018-0082. Copies can 
also be obtained from the U.S. Fish and Wildlife Service, Mississippi 
Ecological Services Field Office (see FOR FURTHER INFORMATION CONTACT). 
We seek information, data, and comments from the public regarding the 
Interior least tern and the PDM plan.

Required Determinations

Clarity of the Proposed Rule

    We are required by Executive Orders 12866 and 12988 and by the 
Presidential Memorandum of June 1, 1998, to write all rules in plain 
language. This means that each rule we publish must:
    (a) Be logically organized;
    (b) Use the active voice to address readers directly;
    (c) Use clear language rather than jargon;
    (d) Be divided into short sections and sentences; and
    (e) Use lists and tables wherever possible.
    If you feel that we have not met these requirements, send us 
comments by one of the methods listed in ADDRESSES. To better help us 
revise the rule, your comments should be as specific as possible. For 
example, you should tell us the numbers of the sections or paragraphs 
that are unclearly written, which sections or sentences are too long, 
the sections where you feel lists or tables would be useful, etc.

National Environmental Policy Act

    We have determined that we do not need to prepare an environmental 
assessment or environmental impact statement, as defined in the 
National Environmental Policy Act (42 U.S.C. 4321 et seq.), in 
connection with regulations adopted pursuant to section 4(a) of 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).

[[Page 56991]]

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, 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. We have determined that 
there are lands of 20 different tribes within the range of the listed 
Interior least tern that may be affected by this proposal. We intend to 
contact each of these Tribes during the open comment period for this 
proposed rule so they may fully evaluate any potential impact of this 
proposed rule and the draft PDM plan.

References Cited

    A complete list of references cited is available on https://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 document is Paul Hartfield of the 
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.

Proposed Regulation Promulgation

    Accordingly, we propose to 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]

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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.

    Dated: August 8, 2019.
Margaret E. Everson,
Principal Deputy Director, U.S. Fish and Wildlife Service, Exercising 
the Authority of the Director for the U.S. Fish and Wildlife Service.
[FR Doc. 2019-23119 Filed 10-23-19; 8:45 am]
 BILLING CODE 4333-15-P