2564 Federal Register / Vol. 86, No. 8 / Wednesday, January 13, 2021 / Rules and Regulations 

thereby subjecting the called party to 

charges. 

* * * * * 

(k) * * * 

(2) * * * 

(iv) A telephone number that the 

provider identifies, based on reasonable 

analytics, as highly likely to be 

associated with a one-ring scam. 

* * * * * 

[FR Doc. 2020–27652 Filed 1–12–21; 8:45 am] 

BILLING CODE 6712–01–P 

DEPARTMENT OF TRANSPORTATION 

Pipeline and Hazardous Materials 

Safety Administration 

49 CFR Parts 106, 107, 171, 172, 173, 

174, 175, 176, 177, 178, 179, and 180 

[Docket No. PHMSA–2018–0082 (HM–260A)] 

RIN 2137–AF43 

Hazardous Materials: Editorial 

Corrections and Clarifications 

Correction 

In rule document 2020–23353 

appearing on pages 83366 through 

83403 in the issue of Monday, December 

21, 2020, make the following correction: 

(1) On page 83366, in the DATES

section, change ‘‘January 20, 2021’’ to 

read ‘‘January 21, 2021.’’ 

(2) On page 83366, in the second 

column, on line twenty-nine change 

‘‘January 20, 2021’’ to read ‘‘January 21, 

2021.’’ 

[FR Doc. C1–2020–23353 Filed 1–12–21; 8:45 am] 

BILLING CODE 1301–00–D 

DEPARTMENT OF THE INTERIOR 

Fish and Wildlife Service 

50 CFR Part 17 

[Docket No. FWS–R4–ES–2018–0082; 

FF09E22000 FXES11130900000 201] 

RIN 1018–BC11 

Endangered and Threatened Wildlife 

and Plants; Removal of the Interior 

Least Tern From the Federal List of 

Endangered and Threatened Wildlife 

AGENCY: Fish and Wildlife Service, 

Interior. 

ACTION: Final rule. 

SUMMARY: We, the U.S. Fish and 

Wildlife Service (Service), are removing 

the inland population of the least tern 

(Interior least tern) (Sterna (now 

Sternula) antillarum), from the Federal 

List of Endangered and Threatened 

Wildlife due to recovery. This 

determination is based on a thorough 

review of the best available scientific 

and commercial data, which indicates 

that the Interior least tern has recovered 

and the threats to the Interior least tern 

have been eliminated or reduced to the 

point that the species no longer meets 

the definition of an endangered species 

or threatened species under the 

Endangered Species Act of 1973, as 

amended (Act). Accordingly, the 

prohibitions and protections provided 

by the Act will no longer apply to the 

Interior least tern. 

DATES: This rule is effective February 

12, 2021. 

ADDRESSES: The proposed and final 

rules, supporting documents, and the 

comments received on the proposed 

rule are available on the internet at 

http://www.regulations.gov under 

Docket No. FWS–R4–ES–2018–0082, at 

https://www.fws.gov/mississippiES/, or 

at https://ecos.fws.gov. 

FOR FURTHER INFORMATION CONTACT: 

Stephen Ricks, Field Supervisor, U.S. 

Fish and Wildlife Service, Mississippi 

Ecological Services Field Office, 6578 

Dogwood View Parkway, Jackson, MS 

39213; telephone (601) 321–1122. 

Individuals who use a 

telecommunications device for the deaf 

(TDD), may call the Federal Relay 

Service at (800) 877–8339. 

SUPPLEMENTARY INFORMATION: 

Executive Summary 

Why we need to publish a rule. Under 

the Act, a species may be removed from 

the Federal List of Endangered and 

Threatened Wildlife (List) if it is 

determined that the species has 

recovered and no longer meets the 

definition of an endangered or 

threatened species. Removing a species 

from the List can only be completed by 

issuing a rule. 

What this document does. This rule 

removes the Interior least tern (Sterna 

(now Sternula) antillarum) from the List 

in title 50 of the Code of Federal 

Regulations (50 CFR 17.11(h)) based on 

its recovery. 

The basis for our action. Under the 

Act, we determine that a species is an 

endangered species or a threatened 

species based on any of five factors: (A) 

The present or threatened destruction, 

modification, or curtailment of its 

habitat or range; (B) overutilization for 

commercial, recreational, scientific, or 

educational purposes; (C) disease or 

predation; (D) the inadequacy of 

existing regulatory mechanisms; or (E) 

other natural or manmade factors 

affecting its continued existence. We 

must consider the same factors when 

removing a species from the List (i.e., 

‘‘delisting’’ a species). We may delist a 

species if we find, after conducting a 

status review based on the best 

scientific and commercial data 

available, that: (1) The species is extinct; 

(2) the species does not meet the 

definition of an endangered species or a 

threatened species (e.g., because it has 

recovered); or (3) the listed entity does 

not meet the statutory definition of a 

species (50 CFR 424.11(e)). We have 

determined that the Interior least tern is 

not in danger of extinction now nor 

likely to become so in the foreseeable 

future based on a comprehensive review 

of its status and listing factors. 

Accordingly, we have determined that 

the species may be delisted based on 

recovery as a result of: (1) A range 

extension; (2) an increase in abundance 

and number of breeding sites; (3) 

resiliency to existing and potential 

threats; (4) the implementation of 

beneficial management practices; and 

(5) changes in existing regulatory 

mechanisms that are more protective of 

migratory bird habitats. 

Peer review and public comment. We 

evaluated the species’ needs, current 

conditions, and future conditions to 

prepare our October 24, 2019, proposed 

rule (84 FR 56977). We sought and 

evaluated comments from independent 

specialists to ensure that our 

determination is based on scientifically 

sound data, assumptions, and analyses. 

We also invited these peer reviewers to 

comment on the draft post-delisting 

monitoring (PDM) plan. We considered 

all comments and information we 

received during the public comment 

period on the proposed delisting rule 

and the draft PDM plan when 

developing this final rule. 

Previous Federal Actions 

On October 24, 2019, we published a 

proposed rule to remove the Interior 

least tern from the Federal List of 

Endangered and Threatened Wildlife 

(84 FR 56977). Please refer to that 

proposed rule for a detailed description 

of previous Federal actions concerning 

this species. The proposed rule and 

supplemental documents are provided 

at http://www.regulations.gov under 

Docket No. FWS–R4–ES–2018–0082 or 

at https://www.fws.gov/mississippiES/. 

Species Information 

Taxonomy and Genetics 

Least terns within the Interior Basin 

of North America were described as 

Sterna antillarum athalassos, a 

subspecies of the eastern least tern (S. 

antillarum antillarum) (Burleigh and 

Federal Register / Vol. 86, No. 8 / Wednesday, January 13, 2021 / Rules and Regulations 2565 

Lowery 1942, pp. 173–177). In 2006, the 

American Ornithologist’s Union 

recognized least terns under a 

previously published genus (Sternula) 

based on mitochondrial DNA phylogeny 

(Bridge et al. 2005, p. 461). Interior least 

tern was one of three subspecies of New 

World (North and South America) least 

terns previously recognized by the 

American Ornithologists’ Union (1957, 

p. 239), including the eastern least tern 

and the California least tern (S. 

antillarum browni). However, due to 

taxonomic uncertainty surrounding 

least tern subspecies at the time of 

listing (50 FR 21784; May 28, 1985), we 

treated the Interior least tern as a 

population of eastern least tern. 

Since that time, genetic analyses of 

North American populations of least 

tern found no evidence of 

differentiation warranting subspecies 

recognition (e.g., Whittier 2001, p. 10; 

Draheim et al. 2010, pp. 813–815; 

Draheim et al. 2012, p. 146). Genetic 

exchange between eastern least terns 

and Interior least terns is occurring at a 

rate greater than three migrants per 

generation between populations 

(Whittier et al. 2006, p. 179). After 

reviewing the best available scientific 

information regarding the taxonomy of 

the Interior least tern, we continue to 

conclude that it is a distinct population 

segment of the eastern least tern 

(Sternula antillarum). 

Species Description 

Least terns are the smallest members 

of the family Laridae, measuring 21 to 

23 centimeters (cm) (8 to 9 inches (in)) 

long with a 56-cm (22-in) wingspan 

(Thompson et al. 1997, pp. 1–2). Sexes 

look alike, characterized in the breeding 

plumage by a black crown, white 

forehead, grayish back and dorsal wing 

surfaces, snowy white undersurfaces, 

orange legs, and a black tipped yellow 

bill. Immature birds have darker 

plumage, a dark bill, and dark eye 

stripes on their white heads. Least terns 

are distinguished from all other North 

American terns by their small size. 

Interior least terns can only be separated 

from eastern and California least terns 

by the geographic area used for nesting. 

Life Span 

Interior least terns are potentially 

long-lived, with records of recapture 

more than 20 years following banding 

(Thompson et al. 1997, p. 15); however, 

the average life span is probably less. 

Nesting Habitat and Behavior 

Least terns begin breeding and nesting 

in their second or third year and breed 

annually throughout their lives 

(Thompson et al. 1997, p. 15). Prior to 

nesting, young birds exhibit some level 

of prospecting behavior (exploratory 

dispersal) across the landscape (e.g., 

Boyd and Thompson 1985, p. 405; Lott 

2012, p. 12; Shigeta in litt. 2014, entire). 

Interior least terns generally nest on 

the ground, in open areas, and near 

appropriate feeding habitat (Lott and 

Wiley 2012, pp. 9–11). Nests are simple 

scrapes in the sand, and nesting sites are 

characterized by coarser and larger 

substrate materials, more debris, and 

shorter and less vegetation compared to 

surrounding areas (Smith and Renken 

1993, p. 501; Stucker 2012, p. 49). 

Typical least tern clutch size is reported 

as two to three eggs (Thompson et al. 

1997, p. 15); however, clutch size may 

vary by location and year (e.g., Szell and 

Woodrey 2003, p. 37; Jones 2012, p. 3). 

Natural nesting habitat features are 

maintained and influenced by 

magnitude and timing of riverine flood 

events (Sidle et al. 1992, p. 134; Renken 

and Smith 1995, pp. 194–195; Pavelka 

in litt. 2012, p. 2). The Interior least tern 

prefers vegetation-free sand or gravel 

islands for nesting, although sand 

banks, point bars, salt flats or plains, 

and beaches may also be used. Interior 

least terns prefer areas remote from trees 

or other vegetation that may hide or 

support predators (Lott and Wiley 2012, 

pp. 9–11). Least terns also nest on 

anthropogenic sites (originating from 

human activity) (Jackson and Jackson 

1985, p. 57; Lott 2006, p. 10) near water 

bodies that contain appropriate and 

abundant prey fishes. Anthropogenic 

sites used by the tern include industrial 

sites (Ciuzio et al. 2005, p. 102; Mills 

2012, p. 2), dredge spoil (Ciuzio et al. 

2005, p. 102), sand pits (Smith 2008, p. 

2), constructed habitats (Stucker 2012, 

pp. 59–66), and rooftops (Boland 2008, 

entire; Watterson 2009, entire). 

Lott and Wiley (2012, pp. 9–11) 

described five physical and biological 

conditions that are necessary for Interior 

least tern nest initiation and successful 

reproduction: 

(1) Nest sites that are not inundated 

(flooded) during egg laying and 

incubation; 

(2) Nesting sites that are not 

inundated until chicks can fly; 

(3) Nesting sites with less than 30 

percent ground vegetation; 

(4) Nesting sites that are more than 76 

meters (m) (250 feet (ft)) from large 

trees; and 

(5) Availability of prey fishes to 

support chick growth until fledging. 

Interior least terns are colonial 

nesters. Colony size may vary from a 

few breeding birds to more than 1,200 

(Jones 2012, p. 3). Populations in some 

river drainages may be limited by 

annual availability of nesting habitat 

(e.g., Missouri River; Stucker 2012, p. 

104), while potential nesting habitat is 

generally abundant and underused in 

other drainages (e.g., Mississippi River; 

U.S. Army Corps of Engineers (USACE) 

2008, pp. 10–13). Nesting site 

conditions (e.g., habitat suitability, flood 

cycles, prey fish abundance, predation 

pressure) can vary significantly from 

year to year in all drainages, resulting in 

wide fluctuations in bird numbers 

(Jones 2012, p. 14) and/or nesting 

success (Smith and Renken 1993, p. 41; 

Lott and Wiley 2012, p. 15). However, 

Interior least terns may re-nest, or 

relocate and re-nest, if nests or chicks 

are destroyed early in the season 

(Massey and Fancher 1989, pp. 353– 

354; Thompson et al. 1997, p. 15). 

Interior least tern chicks leave their 

nests within a few days of hatching 

(semiprecocial), but remain near the 

nests and are fed by their parents until 

fledging (Thompson et al. 1997, pp. 14– 

15). 

Food and Foraging Habitat 

Interior least terns are primarily 

piscivores (fish-eaters), and feed 

opportunistically on small fish species 

or the young of larger fish species. Prey 

species include native species such as 

shad (Dorosoma spp.), carps and 

minnows (Cyprinidae), freshwater drum 

(Aplodinotus grunniens), largemouth 

bass (Micropterus salmoides), white 

bass (Morone chrysops), sunfishes 

(Lepomis spp.), and top minnows 

(Fundulus spp.), as well as invasive 

species such as silver and bighead carp 

(Hypophthalmichthys spp.) (USACE 

2008, pp. 16, 26). On the Missouri River, 

prey species include emerald shiner 

(Notropis atherinoides), sand shiner 

(Notropis stramineus), spotfin shiner 

(Cyprinella spiloptera), and bigmouth 

buffalo (Ictiobus cyprinellus) (Stucker 

2012, p. 6). Least terns will also 

occasionally feed on aquatic or marine 

invertebrates (Thompson et al. 1997, pp. 

6–7). Riverine foraging habitats and fish 

abundance may be influenced by 

stochastic (random) hydrological 

conditions and events (i.e., flow, and 

flood timing and magnitude), and 

channel engineering (Schramm 2004, 

pp. 307, 321–323). 

In the Missouri River drainage, 

Interior least terns forage for fish in 

shallow water habitats and within 12 

kilometers (km) (7 miles (mi)) from 

colony sites (Stucker 2012, p. 24). In the 

Lower Mississippi River, foraging terns 

have been observed feeding in a variety 

of habitats within 3 km (2 mi) of colony 

sites (Jones 2012, pp. 5–6). 

2566 Federal Register / Vol. 86, No. 8 / Wednesday, January 13, 2021 / Rules and Regulations 

Migration and Winter Habitat 

Interior least tern fall migrations 

generally follow major river basins to 

their confluence with the Mississippi 

River and then south to the Gulf of 

Mexico; however, late summer 

observations of least terns more than 

150 km (93 mi) from major river 

drainages indicate that some birds 

migrate over land (Thompson et al. 

1997, p. 16). Interior least terns gather 

in flocks in August prior to migration. 

Once they reach the Gulf Coast, they 

cannot be distinguished from other least 

tern populations en route to, or within, 

their winter habitats (i.e., Gulf of 

Mexico, Caribbean islands, Central and 

South America); therefore, the limited 

information on migration and winter 

habitat is inclusive of other populations 

(i.e., Caribbean, Gulf Coast, East Coast). 

Least terns appear to migrate in small, 

loose groups along or near shore, 

feeding in shallows and resting onshore 

(Thompson et al. 1997, pp. 4–6). Very 

little is known of least tern winter 

habitats, other than that the birds are 

primarily observed along marine coasts, 

in bays and estuaries, and at the mouths 

of rivers (Thompson et al. 1997, p. 6). 

Breeding/Natal Site Fidelity and 

Dispersal 

Breeding-site fidelity for least terns 

varies in different populations and 

breeding areas. Return rates of banded 

adults to the sites where they were 

banded was 36 to 86 percent in 

California colonies; 42 percent on the 

Mississippi River; 28 percent on the 

central Platte River, Nebraska; and 81 

percent at Quivira National Wildlife 

Refuge in Kansas and on the Cimarron 

River in Oklahoma (Thompson et al. 

1997, p. 16). Fidelity to natal site is also 

variable and difficult to estimate 

because re-sightings or recaptures of 

terns banded as chicks have been 

limited. Estimates of natal site fidelity 

have varied from 5 percent on the 

Mississippi River, to 82 percent in 

Kansas and Oklahoma (Thompson et al. 

1997, p. 16). 

Site fidelity in least terns may be 

affected by physical habitat variables or 

the extent and type of predation 

(Atwood and Massey 1988, p. 394). As 

noted above, least terns are strong fliers 

and can relocate if conditions on natal 

or previous-year nesting grounds 

become unfavorable. A study of eastern 

least terns found an average 22 percent 

turnover rate in nesting colony sites, 

primarily due to changes in habitat 

condition or disturbance (Burger 1984, 

p. 66). 

Lott et al. (2013, pp. 3617–3618) 

found that 50 to 90 percent of reported 

recaptures occurred less than 26 km (16 

mi) from the original banding sites, 

while more than 90 percent dispersed 

less than 96 km (59 mi), indicating a 

high degree of adult site fidelity and 

natal site philopatry (remaining near 

their point of origin). However, long 

distance dispersal (up to 1,000 km; 621 

mi) has been documented (e.g., Renken 

and Smith 1995, pp. 196–198; Boyd and 

Sexson 2004, p. 88; Lott et al. 2013, pp. 

3617–3618), and may not be uncommon 

(Boyd and Thompson 1985, p. 405). 

Least tern nesting has also been 

documented in Brazil (Rodrigues et al. 

2010, entire) and Hawaii (Conant et al. 

1991, entire; Pyle et al. 2001, entire). 

During 2014, an Interior least tern 

banded in the Missouri River drainage 

was captured in Japan, along with 

another unbanded tern (Shigeta in litt. 

2014). 

Predation 

Interior least tern eggs, chicks, and 

adults are prey for a variety of mammal 

and bird predators. Reported predators 

include birds (e.g., crows, herons, owls, 

and hawks), mammals (e.g., fox, coyote, 

racoon, and skunk), and catfish, as well 

as domesticated and feral dogs and cats 

(Thompson et al. 1997, pp. 10–11). The 

cryptic coloration of eggs and chicks, 

the secretive behavior of chicks, and the 

mobbing behavior (attack flights on 

potential predators) of adults, all serve 

to protect eggs and chicks from 

predators (Thompson et al. 1997, p. 11). 

Location and size of nesting colonies 

also has a significant influence on 

degree of predation. Interior least tern 

reproductive success is higher on island 

colonies as compared to connected 

sandbar colonies, and when water levels 

maintain isolation of islands and 

nesting bars from mammalian predators 

(Smith and Renken 1993, p. 42; Szell 

and Woodrey 2003, p. 41). Additionally, 

significantly higher rates of predation 

were documented in larger colonies 

compared to smaller colonies (Burger 

1984, p. 65). 

Historical Distribution and Abundance 

The Service defined the historical 

breeding range of the Interior least tern 

to include the Colorado (in Texas), Red, 

Rio Grande, Arkansas, Missouri, Ohio, 

and Mississippi Rivers systems from 

Montana south to Texas, and from New 

Mexico east to Indiana (50 FR 21784; 

May 28, 1985). However, in order to 

avoid confusion with eastern least tern, 

the Service excluded the Mississippi 

River south of Baton Rouge, Louisiana, 

the Texas Coast, and a 50-mile zone 

inland from the coast of Texas from the 

protected range of Interior least tern (50 

FR 21784, May 28, 1985, p. 21789). 

The historical distribution and 

abundance of the Interior least tern 

within this range is poorly documented. 

Hardy (1957, entire) provided the first 

information on least tern distribution on 

large interior rivers, documenting 

records of occurrence and nesting in the 

Mississippi, Ohio, Missouri, Arkansas, 

and Red River drainages. Downing 

(1980, entire) published results from a 

rapid aerial/ground survey of a subset of 

these rivers, identifying additional 

nesting populations within the range 

noted above, and estimated the Interior 

least tern population at approximately 

1,250 adult birds. Ducey (1981, pp. 10– 

50) doubled the number of known 

nesting sites, including areas between 

the scattered observations reported in 

Hardy (1957, entire). Ducey also 

extended the northern distribution of 

the Interior least tern to include the 

Missouri River below Garrison Dam in 

North Dakota and Fort Peck Dam in 

Montana. These three publications 

(Hardy 1957, entire; Downing 1980, 

entire; Ducey 1981, entire) provide the 

primary historical sources of 

information about the Interior least 

tern’s geographic range, and were used 

to reach the estimate of 1,400 to 1,800 

adults rangewide in the listing rule (50 

FR 21784; May 28, 1985). 

Current Distribution and Abundance 

The current east to west distribution 

of summer nesting Interior least terns 

encompasses more than 18 degrees of 

longitude, or 1,440 km (900 mi), from 

the Ohio River, Indiana and Kentucky, 

west to the Upper Missouri River, 

Montana. The north to south 

distribution encompasses over 21 

degrees of latitude (more than 2,300 km 

(1,450 mi)) from Montana to southern 

Texas. Interior least terns currently nest 

along more than 4,600 km (2,858 mi) of 

river channels across the Great Plains 

and the Lower Mississippi Valley (Lott 

et al. 2013, p. 3623), with nesting 

colonies found in 18 States, including: 

Montana, North Dakota, South Dakota, 

Nebraska, Colorado, Iowa, Kansas, 

Missouri, Illinois, Indiana, Kentucky, 

New Mexico, Oklahoma, Arkansas, 

Tennessee, Texas, Louisiana, and 

Mississippi. As noted above, this does 

not include least tern colonies nesting 

along the coasts of Texas, Louisiana, 

and Mississippi. 

Rangewide surveys in 2005 estimated 

an approximate minimum adult 

population size of 17,500, with nesting 

occurring in more than 480 colonies 

spread across 18 States, which is likely 

an underestimate given imperfect 

detection of adults and survey coverage 

of potential habitat (Lott 2006, pp. 10– 

21, 50). Lott (2006, pp. 13–15) also 

Federal Register / Vol. 86, No. 8 / Wednesday, January 13, 2021 / Rules and Regulations 2567 

provided counts for 21 populations or 

population segments that were 

unknown at the time of listing, which 

collectively support more than 2,000 

terns. 

Population Trends 

The Interior least tern has 

demonstrated a positive population 

trend, increasing by almost an order of 

magnitude (or 10 times what it was 

prior) since it was listed in 1985. After 

it was listed, researchers increased 

survey effort and the geographical 

extent of the area surveyed, producing 

sufficient Interior least tern count data 

to analyze population trends for several 

river reaches that support persistent 

breeding colonies. Kirsch and Sidle 

(1999, p. 473) reported a rangewide 

population increase to over 8,800 adults 

in 1995, and found that 29 of 31 Interior 

least tern locations with multi-year 

monitoring data were either increasing 

or stable. Lott (2006, p. 50) reported an 

increase to over 17,500 adult birds in 

2005, forming 489 colonies in 68 

distinct geographic sites. While some 

proportion of the rangewide increase in 

adult bird counts and number of nesting 

colonies are likely attributable to 

increased survey efforts and improved 

survey techniques, both Kirsch and 

Sidle (1999, p. 473), and Lott and 

Sheppard (2017a, pp. 50–52) 

documented multiple drainage 

population increases using multi-year 

counts. 

Lott (2006, p. 92) conceptualized the 

Interior least tern functioning as a large 

metapopulation (a regional group of 

connected populations of a species), 

which might also include least terns on 

the Gulf Coast. Using available 

information on dispersal of least terns, 

Lott et al. (2013, pp. 3616–3617) defined 

16 discrete breeding populations of 

Interior least tern, with 4 major 

geographical breeding populations 

(population complexes) accounting for 

more than 95 percent of all adult birds 

and nesting sites throughout the range. 

Portions of these four population 

complexes have experienced multi-year 

monitoring to different degrees. While 

some local (colony, subpopulation) 

declines have been documented, the 

Interior least tern has experienced a 

dramatic increase in range and numbers 

since listing and development of the 

recovery plan (e.g., Kirsch and Sidle 

1999, p. 473; Lott 2006, pp. 10–49). 

There has been no reported extirpation 

of any population or subpopulation 

since the species was listed in 1985. 

Recovery Criteria 

Section 4(f) of the Act directs us to 

develop and implement recovery plans 

for the conservation and survival of 

endangered and threatened species 

unless we determine that such a plan 

will not promote the conservation of the 

species. Recovery plans must, to the 

maximum extent practicable, include 

‘‘objective, measurable criteria which, 

when met, would result in a 

determination, in accordance with the 

provisions [of section 4 of the Act], that 

the species be removed from the list.’’ 

Recovery plans provide a roadmap for 

us and our partners on methods of 

enhancing conservation and minimizing 

threats to listed species, as well as 

measurable criteria against which to 

evaluate progress towards recovery and 

assess the species’ likely future 

condition. However, they are not 

regulatory documents and do not 

substitute for the determinations and 

promulgation of regulations required 

under section 4(a)(1) of the Act. A 

decision to revise the status of a species, 

or to delist a species is ultimately based 

on an analysis of the best scientific and 

commercial data available to determine 

whether a species is no longer an 

endangered species or a threatened 

species, regardless of whether that 

information differs from the recovery 

plan. 

There are many paths to 

accomplishing recovery of a species, 

and recovery may be achieved without 

all of the criteria in a recovery plan 

being fully met. For example, one or 

more criteria may be exceeded while 

other criteria may not yet be 

accomplished. In that instance, we may 

determine that the threats are 

minimized sufficiently and the species 

is robust enough that it no longer meets 

the definition of an endangered species 

or a threatened species. In other cases, 

we may discover new recovery 

opportunities after having finalized the 

recovery plan. Parties seeking to 

conserve the species may use these 

opportunities instead of methods 

identified in the recovery plan. 

Likewise, we may learn new 

information about the species after we 

finalize the recovery plan. The new 

information may change the extent to 

which existing criteria are appropriate 

for identifying recovery of the species. 

The recovery of a species is a dynamic 

process requiring adaptive management 

that may, or may not, follow all of the 

guidance provided in a recovery plan. 

The Service approved the Interior 

Least Tern Recovery Plan on September 

19, 1990 (Service 1990, entire). The 

objective of the recovery plan was to 

establish standards for recovery that 

may lead to delisting the Interior least 

tern. Recovery criteria are the values by 

which it is determined that a recovery 

plan objective has been reached. 

Recovery criteria identified in the 

recovery plan were designed to assure 

the protection of essential habitat by 

removal of threats at that time and 

habitat enhancement, establish agreedupon management plans, and attain a 

rangewide population of 7,000 birds at 

the levels listed below (for five major 

river drainages throughout the Interior 

least tern’s range): 

(1) Adult birds in the Missouri River 

system will increase to 2,100, and 

remain stable for 10 years. 

(2) Current numbers of adult birds 

(2,200–2,500) on the Lower Mississippi 

River will remain stable for 10 years. 

(3) Adult birds in the Arkansas River 

system will increase to 1,600, and 

remain stable for 10 years. 

(4) Adult birds in the Red River 

system will increase to 300, and remain 

stable for 10 years. 

(5) Current numbers of adult birds 

(500) in the Rio Grande River system 

will remain stable for 10 years. 

Primary recovery tasks conducted to 

achieve the recovery objective and 

drainage population targets included: 

(1) Determining the distribution and 

population trends of the Interior least 

tern; 

(2) Determining habitat requirements 

and status; 

(3) Protecting, enhancing, and 

increasing Interior least tern 

populations; and 

(4) Preserving and enhancing the 

tern’s habitats. 

These are briefly reviewed below. 

Rangewide Population Criterion to 

Delist 

The Interior least tern rangewide 

numerical recovery criterion (7,000 

birds) has been met and has been 

exceeded since 1994 (see Service 2013, 

pp. 7–127). Using rangewide seasonal 

count data from 1984 (722 terns) 

through 1995 (8,859 terns), Kirsch and 

Sidle (1999, pp. 473–477) demonstrated 

achievement of the numerical recovery 

criterion and a positive population 

growth trend. They noted that most of 

the Interior least tern increase had 

occurred on the Lower Mississippi 

River, observed that population 

increases were not supported by 

fledgling success estimates available at 

that time, and hypothesized that Interior 

least tern increases were possibly due to 

immigration surges from a more 

abundant least tern population 

inhabiting the Gulf Coast (Kirsch and 

Sidle 1999, p. 478). 

Lott (2006, entire) organized, 

compiled, and reported a synchronized 

rangewide count for Interior least tern in 

2005, finding tern numbers had doubled 

2568 Federal Register / Vol. 86, No. 8 / Wednesday, January 13, 2021 / Rules and Regulations 

since 1995 (17,591 birds rangewide; 62 

percent occurring along the Lower 

Mississippi River), equaling or 

exceeding least tern population 

estimates along the U.S. Gulf Coast (Lott 

2006, p. 50). Since 2006, the majority of 

Interior least terns continue to be 

reported from the Lower Mississippi 

River (Service 2013, p. 11). As did 

Kirsch and Sidle (1999, p. 478), Lott 

(2006, p. 52) also hypothesized a wider 

least tern metapopulation, which 

included Gulf Coast and interior 

subpopulations, and the possibility of a 

shift of birds from the Gulf Coast to 

inland habitats due to the presence of 

better nesting conditions, particularly 

on the Lower Mississippi River. 

However, there are few data directly 

supporting the Kirsch and Sidle (1999, 

pp. 473–477) or the Lott (2006, p. 52) 

immigration hypotheses as a factor in 

the 20-year increase in Interior least tern 

counts. There has not been a complete 

or organized rangewide count since 

2005; however, some geographic 

segments continue to be annually 

monitored, including portions of the 

Missouri (USACE in litt. 2017, entire), 

Platte (Keldsen and Baasch 2016, 

entire), Red (Stinson in litt. 2017, 

entire), Arkansas (Cope in litt. 2017, 

entire; Nupp 2016, entire), and Wabash 

Rivers (Mills 2018, entire). These partial 

counts indicate that we continue to 

exceed the recovery goal of 7,000 birds 

(Service 2013, pp. 11–12). 

Numerical Population Targets 

In addition to the numerical 

population targets identified in the 

recovery plan for five major river 

drainages throughout the tern’s range 

(see above), sub-drainage targets were 

also identified for the Missouri and 

Arkansas River drainages (Service 1990, 

pp. 28–29). Drainage and sub-drainage 

numerical targets were based upon the 

opinions of technical experts and State 

and Federal resource agencies of the 

potential for population increase at the 

time (Service 1990, p. 28). The drainage 

system population size targets have 

been exceeded in three of the five 

targeted drainages (Lower Mississippi 

(more than 25 years), Red (more than 15 

years), and Arkansas Rivers (more than 

10 years) (see Service 2013, pp. 22–26). 

As to the Rio Grande drainage, it is now 

recognized that the subpopulations 

found within the drainage represent 

recent exploitation of anthropogenic 

habitats (i.e., salt flats and reservoirs) 

and are not historical habitats; thus, 

these areas were inappropriately 

designated as ‘‘essential’’ segments of 

the tern’s ecosystem in the recovery 

plan (Service 2013, pp. 26–27). 

Therefore, numerical targets originally 

set for the Rio Grande drainage are no 

longer considered necessary for this 

species’ recovery. 

As to the Missouri River drainage, the 

Interior least tern population size has 

remained relatively stable 

(approximately 1,600 birds) over the 29 

years since recovery criteria were 

identified (Service 2013, p. 11), and 

neither the drainage population target 

(2,100) nor many of the targets 

identified for Missouri River drainage 

segments have been consistently met 

(Service 2013, pp. 14–21). However, 

since the tern was listed, the Missouri 

River system has received a significant 

commitment of conservation attention 

and resources (USACE 2017a, pp. 1–17), 

particularly in comparison to other 

drainages that have experienced 

increases in tern populations. Based on 

the lack of increase in population, in 

light of the substantial commitment of 

resources, we conclude that that the 

Missouri River drainage is likely at the 

carrying capacity of the available habitat 

(Service 2013, pp. 14–21), and the 

recovery goal of 2,100 birds is not 

achievable. Periodic downward trends 

observed in a few Missouri drainage 

subpopulations have been reversed by 

habitat improvement following major 

floods (Pavelka 2012, p. 2), or offset by 

upward trends in other subpopulations 

(Pavelka 2012, pp. 7–8; Lott and 

Sheppard 2017a, pp. 49–53), indicating 

that the Missouri River drainage Interior 

least tern population is sustainable and 

recovered. 

In short, some drainage population 

targets identified in the 1990 recovery 

plan have not been fully met, as the Rio 

Grande was inappropriately considered 

‘‘essential’’ (see above) and the Missouri 

River drainage appears to be at carrying 

capacity and incapable of reaching the 

2,100 target identified in the recovery 

plan. However, the inability to meet 

these drainage and sub-drainage targets 

have been offset by large increases in 

the Interior least tern populations 

within the Arkansas, Red, and Lower 

Mississippi Rivers, and by the discovery 

of numerous subpopulation segments 

throughout the Interior Basin that were 

either unrecognized or not occupied at 

the time of listing and recovery plan 

development, increasing the number of 

known breeding colonies from a few 

dozen at listing to more than 480 (Lott 

2006, p. 10; also see Service 2013, pp. 

31–33). 

Habitat Criteria 

Recovery plan delisting criteria 

required the protection, enhancement, 

and restoration of essential Interior least 

tern breeding habitats (Service 1990, pp. 

28–29). Beyond the identification of 

specific river reaches as ‘‘essential,’’ 

habitat parameters were not defined, nor 

were specific objective and measurable 

criteria for their protection identified. 

The recovery plan outlined several tasks 

to protect and enhance Interior least 

tern habitats, including managing water 

flows, modifying construction activities, 

and protecting all areas identified as 

‘‘essential’’ across the species’ range 

through acquisition, easements, or 

agreements (Service 1990, pp. 29–50). 

Recovery tasks identified for 

managing water flows are primarily 

relevant to portions of the Missouri, 

Red, and Arkansas River drainages, 

which cumulatively encompass about 

20 percent of the Interior least tern 

breeding population. The majority of the 

remainder of the species’ range occurs 

along unimpounded sections of the 

Mississippi River not subject to flow 

management. Over the past two 

decades, protective flow management 

actions have been identified and 

incorporated by USACE Northwest 

Division into their Missouri River Bank 

Stabilization and Navigation Project and 

operations of the Missouri River 

Reservoir System, including seasonal 

reservoir flow management to reduce 

nesting mortalities, and for sandbar 

augmentation and modification, 

vegetation management, predation 

control, human restriction measures, 

and water-level management for 

reservoir nesting areas (USACE 2017a, 

pp. 139–143). In the Southern Plains, 

USACE Southwest Division civil works 

projects in the Arkansas, Canadian, and 

Red River systems within Arkansas, 

Oklahoma, and Texas use reservoir 

storage and operation to reduce 

flooding; minimize land bridging, 

predation, and human disturbance 

during Interior least tern nesting season; 

and enhance nesting habitats at other 

times of the year (USACE 2002, pp. 3– 

4; 2016, pp. 18–20). These water 

management practices have been 

adopted by the respective USACE 

Divisions and Districts as best 

management practices (BMPs) and with 

commitments to continue into the future 

regardless of the future status of the 

Interior least tern under the Act (USACE 

2016, pp. 2, 24; 2018, pp. 4–13–4–17). 

Recovery tasks for modifying 

construction activities within river 

channels have been successfully 

implemented across Interior least tern 

habitats that are managed under USACE 

programs in jurisdictional waters 

(categories of waters defined under the 

Clean Water Act (33 U.S.C. 1251 et seq.) 

that include navigable waters, interstate 

waters, tributaries, impoundments, etc.). 

Construction practices critical to 

maintaining and protecting nesting 

Federal Register / Vol. 86, No. 8 / Wednesday, January 13, 2021 / Rules and Regulations 2569 

habitats have been incorporated into 

USACE river management programs as 

standard operating procedures (SOPs) or 

BMPs, including construction timing 

and work zone buffers to avoid 

disturbance of nesting colonies, dike 

modifications to protect and maintain 

habitat values, and dredge material 

disposal methods beneficial to 

maintaining nesting sand bars and 

islands (e.g., USACE 2013, pp. 69–72; 

USACE 2016, p. 21). Other SOPs and 

BMPs incorporated into USACE 

programs promote ecosystem 

productivity important to tern foraging, 

including articulated concrete mat 

design, use of hardpoints in lieu of 

revetment, and strategic placement of 

woody debris within channels (e.g., 

USACE 2013, p. 71). These existing 

management strategies and programs 

(USACE 2013, entire; 2016, entire; 

2017a, entire) are protective of waters 

and habitats managed by USACE that 

support about 80 percent of the Interior 

least tern’s range and have been a major 

factor in the recovery of the species. All 

USACE programs currently provide for 

adaptive management into the future, 

independent of the Federal listing status 

of the Interior least tern (USACE 2013, 

p. 71; 2016, pp. 2, 24; 2018, pp. 4–13– 

4–17). 

New information developed over the 

past three decades relative to the 

ecology of Interior least tern and its 

habitats indicate that recovery tasks to 

protect ‘‘essential’’ habitats across the 

species’ range through acquisition or 

easements are neither cost-effective nor 

necessary. Riverine habitat for Interior 

least terns is not static, and clearly 

experiences dramatic local or regional 

annual (at times, daily) variation in 

location, quantity, and quality. 

Describing and quantifying habitat 

quality is difficult, given the wide 

variety of conditions the bird is known 

to exploit (e.g., rivers, reservoirs, 

rooftops). 

The Interior least tern adjusts to 

habitat variation and change over its 

range through metapopulation dynamics 

(Hanski and Gilpin 1991, entire; Lott et 

al. 2013, p. 3620; Lott and Sheppard 

2017, entire). A metapopulation consists 

of a network of populations with similar 

dynamics that are buffered against 

extinction by abandoning areas as 

habitats degrade, and dispersing and 

exploiting suitable habitats as they 

become available. Therefore, the 

importance of specific habitat segments 

to the species is likely to change with 

time. Within large metapopulations of 

mobile species, small subpopulations 

(or colonies within subpopulations) may 

occur in habitats where recruitment is 

inconsistent or may not exceed 

mortality (i.e., population sinks), but 

which are maintained by immigration 

from colonies where recruitment 

exceeds mortality (i.e., population 

sources). While exploitation of 

anthropogenic habitats by Interior least 

terns may indicate a lack of suitable 

habitat in an area, it may also indicate 

an overall population or subpopulation 

expansion. Sink colonies also play 

important roles in large 

metapopulations by providing 

opportunities for range expansion, and/ 

or redundancy from episodic stochastic 

impacts to preferred natural habitats. 

While some colony sites may be 

periodic or consistent population sinks, 

there is no evidence that they are 

detracting from the Interior least tern’s 

rangewide survival (e.g., Lott and 

Sheppard 2017a, p. 51), particularly in 

consideration of the substantial increase 

in the known number and size of tern 

colonies over the past two decades, and 

the expansion of the species’ 

distribution outside of its historical 

range (i.e., Illinois, New Mexico, central 

Texas, Colorado; see Service 2013, pp. 

31–33). 

Based upon this understanding of 

Interior least tern population dynamics 

and habitat use, the recovery task of 

protecting all areas identified in 1990 as 

‘‘essential’’ across the species’ range 

through acquisition or easements is not 

necessary for the conservation of the 

species. This conclusion is supported by 

the increase in the species’ range and 

abundance over the past 30 years 

without protections achieved through 

such acquisition or easements. Although 

some Interior least tern nesting colonies 

occur on protected public lands such as 

National Wildlife Refuges, they 

represent only a small portion (less than 

2 percent) of the rangewide population. 

Additionally, as noted above, existing 

management agreements, strategies, and 

programs within jurisdictional waters 

are protective of the habitats that 

support about 80 percent of the Interior 

least tern population (USACE 2013, 

entire; 2016, entire; 2017, entire). 

While the majority (80 percent) of 

Interior least tern nesting colonies are 

known from jurisdictional waters with a 

strong Federal connection with 

navigation systems or reservoirs, the 

remaining nesting colonies occur along 

rivers with a more limited Federal 

nexus, or on mining and industrial sites 

adjacent to or near rivers and reservoirs. 

On about 10 percent of these, Federal, 

State, and/or private conservation 

partnerships have developed and 

implemented conservation agreements 

and management programs beneficial to 

Interior least tern as well as other at-risk 

or endangered species. These programs 

generally post or restrict access, control 

predators, and conduct monitoring 

during nesting season, as well as 

conduct vegetation control and public 

education as opportunities present. 

In the Platte River drainage, the Tern 

and Plover Conservation Partnership 

was initiated in 1999, at the University 

of Nebraska, School of Natural 

Resources. This partnership consists of 

a group of State, industrial, Federal, and 

other cooperators having an interest in 

tern and plover conservation and 

management on and along the Platte, 

Loup, and Elkhorn Rivers, with 

emphasis on nesting areas associated 

with sand and gravel mines, lake shore 

housing developments, and dredging 

operations (University of NebraskaLincoln 2019, entire). Long-term 

management of Interior least tern 

habitats in the Platte River drainage is 

also assured by an adaptive 

management plan developed and 

implemented by a partnership of State 

and industrial water users in Nebraska, 

Colorado, and Wyoming under the 

Platte River Recovery Implementation 

Program (Platte River Recovery 

Implementation Program 2019, entire). 

This program, initiated in 1997, also 

targets management needs of the 

endangered pallid sturgeon 

(Scaphirhynchus albus) and whooping 

crane (Grus americana), and the 

threatened piping plover (Charadrius 

melodus). Since both programs target 

other listed species with similar habitat 

requirements, and the Interior least tern 

is State-listed as endangered, these 

conservation programs and efforts are 

expected to continue regardless of a 

change in the Federal status of this 

species. 

Interior least tern management in the 

Wabash River drainage began with the 

1986 discovery of a single nesting pair 

on Gibson Generating Station property, 

Gibson County, Indiana (Hayes and Pike 

2011, entire; Mills 2018, pp. 2–5). This 

colonization led to site monitoring, 

predator control, and other protective 

measures, including vegetation control, 

water management, and habitat 

management and creation, resulting in 

increasing numbers of terns and 

expansion of nesting colonies to 

multiple sites on public and private 

properties in the vicinity (Hayes and 

Pike 2011, entire). In 1999, management 

was formalized by development of a 

habitat conservation plan, which was 

renewed and revised in 2004, 2011, and 

2018, by Duke Energy Corporation 

(Hayes and Pike 2011, entire). The 

Indiana Nongame and Endangered 

Wildlife Program continues to 

coordinate conservation and monitoring 

efforts on industrial and river sites along 

2570 Federal Register / Vol. 86, No. 8 / Wednesday, January 13, 2021 / Rules and Regulations 

the Wabash River by Duke Energy, the 

Service, and other Indiana Department 

of Natural Resources personnel and 

contractors (Mills 2018, p. 14). Since the 

Interior least tern may continue to be 

protected by the State of Indiana, 

management and monitoring is expected 

to continue to some degree, regardless of 

a change in the Federal status of species. 

To various degrees, a number of 

additional small, localized, and often 

temporary breeding colonies of Interior 

least tern and their habitats have been 

managed, protected, and monitored at 

industrial, municipal, and reservoir 

sites under the Act’s conservation 

(sections 6, 7(a)(1), and 10) or 

consultation (section 7(a)(2)) 

requirements. Managed sites have 

included coal mines (e.g., Tanner and 

Hart 1998, entire), rooftops (e.g., Boylan 

2008, entire), and small reservoirs (e.g., 

Nelson 2010, entire). Such efforts may 

or may not continue when the tern is 

delisted; however, it is also likely that 

the tern will continue to exploit small 

areas of suitable habitats as they are 

available and encountered in its range. 

While such populations contribute some 

small benefit to the rangewide 

redundancy and representation of the 

tern (see discussion of Population 

Trends, above), they cumulatively 

represent less than 2 percent of the 

summer nesting population and their 

success or failure within individual 

sites has little impact on the rangewide 

conservation status of the Interior least 

tern. 

In summary, the expansion of the 

numbers and distribution of the Interior 

least tern, and its adaptation to and 

exploitation of anthropogenic habitats 

over the past several decades, indicate 

that the species is no longer 

conservation-reliant. Potential threats 

identified at the time of listing have 

been removed or ameliorated by 

conservation actions of multiple 

conservation partners, most principally 

the USACE, for more than 20 years. 

These actions have assisted in recovery 

of the species as reflected in the large 

number of individuals rangewide, stable 

to increasing drainage populations since 

listing, and a high number of selfsustaining colonies in 18 States. 

Furthermore, our partners in USACE 

Divisions and Districts within the range 

of the Interior least tern have 

cooperatively modified their programs 

to provide for the long-term 

management of nesting and foraging 

habitats for about 80 percent of the 

rangewide population of the species 

(USACE 2013, entire; 2016, entire; 2017, 

entire). Another 10 percent of the 

population is managed by State and 

private partnerships, which are 

expected to continue based upon State 

status and regulations. Regarding the 

remaining 10 percent of the population 

that nest in habitats with minimal or no 

management, while these areas 

contribute to redundancy and 

representation for the species, their 

success or failure within these sites is 

not essential to the continued existence 

of the Interior least tern. 

Summary of Factors Affecting the 

Species 

Section 4 of the Act (16 U.S.C. 1533) 

and its implementing regulations (50 

CFR part 424) set forth the procedures 

for determining whether a species is an 

‘‘endangered species’’ or a ‘‘threatened 

species.’’ The Act defines an 

‘‘endangered species’’ as a species that 

is in danger of extinction throughout all 

or a significant portion of its range, and 

a ‘‘threatened species’’ as a species that 

is likely to become an endangered 

species within the foreseeable future 

throughout all or a significant portion of 

its range. The Act requires that we 

determine whether any species is an 

‘‘endangered species’’ or a ‘‘threatened 

species’’ because of any of the following 

factors: 

(A) The present or threatened 

destruction, modification, or 

curtailment of its habitat or range; 

(B) Overutilization for commercial, 

recreational, scientific, or educational 

purposes; 

(C) Disease or predation; 

(D) The inadequacy of existing 

regulatory mechanisms; or 

(E) Other natural or manmade factors 

affecting its continued existence. 

These factors represent broad 

categories of natural or human-caused 

actions or conditions that could have an 

effect on a species’ continued existence. 

In evaluating these actions and 

conditions, we look for those that may 

have a negative effect on individuals of 

the species, as well as other actions or 

conditions that may ameliorate any 

negative effects or may have positive 

effects. 

We use the term ‘‘threat’’ to refer in 

general to actions or conditions that are 

known to or are reasonably likely to 

negatively affect individuals of a 

species. The term ‘‘threat’’ includes 

actions or conditions that have a direct 

impact on individuals (direct impacts), 

as well as those that affect individuals 

through alteration of their habitat or 

required resources (stressors). The term 

‘‘threat’’ may encompass—either 

together or separately—the source of the 

action or condition or the action or 

condition itself. 

However, the mere identification of 

any threat(s) does not necessarily mean 

that the species meets the statutory 

definition of an ‘‘endangered species’’ or 

a ‘‘threatened species.’’ In determining 

whether a species meets either 

definition, we must evaluate all 

identified threats by considering the 

expected response by the species, and 

the effects of the threats—in light of 

those actions and conditions that will 

ameliorate the threats—on an 

individual, population, and species 

level. We evaluate each threat and its 

expected effects on the species, then 

analyze the cumulative effect of all of 

the threats on the species as a whole. 

We also consider the cumulative effect 

of the threats in light of those actions 

and conditions that will have positive 

effects on the species—such as any 

existing regulatory mechanisms or 

conservation efforts. The Secretary of 

the Interior (Secretary) determines 

whether the species meets the definition 

of an ‘‘endangered species’’ or a 

‘‘threatened species’’ only after 

conducting this cumulative analysis and 

describing the expected effect on the 

species now and in the foreseeable 

future. 

We must consider these same five 

factors in delisting a species. We may 

delist a species according to 50 CFR 

424.11(e) if the best available scientific 

and commercial data indicate that: (1) 

The species is extinct; (2) the species 

does not meet the definition of an 

endangered species or a threatened 

species; or (3) the listed entity does not 

meet the statutory definition of a 

species. 

A recovered species is one that no 

longer meets the Act’s definition of 

endangered species or threatened 

species. Determining whether a species 

is recovered requires consideration of 

the same five categories of threats 

specified in section 4(a)(1) of the Act. 

For species that are already listed as 

endangered or threatened, this analysis 

of threats is an evaluation of both the 

threats currently facing the species and 

the threats that are reasonably likely to 

affect the species in the foreseeable 

future following delisting or 

downlisting (i.e., reclassification from 

endangered to threatened) and the 

removal or reduction of the Act’s 

protections. 

The Act does not define the term 

‘‘foreseeable future,’’ which appears in 

the statutory definition of ‘‘threatened 

species.’’ Our implementing regulations 

at 50 CFR 424.11(d) set forth a 

framework for evaluating the foreseeable 

future on a case-by-case basis. The term 

foreseeable future extends only so far 

into the future as we can reasonably 

determine that both the future threats 

and the species’ responses to those 

Federal Register / Vol. 86, No. 8 / Wednesday, January 13, 2021 / Rules and Regulations 2571 

threats are likely. In other words, the 

foreseeable future is the period of time 

in which we can make reliable 

predictions. ‘‘Reliable’’ does not mean 

‘‘certain’’; it means sufficient to provide 

a reasonable degree of confidence in the 

prediction. Thus, a prediction is reliable 

if it is reasonable to depend on it when 

making decisions. 

It is not always possible or necessary 

to define foreseeable future as a 

particular number of years. Analysis of 

the foreseeable future uses the best 

scientific and commercial data available 

and should consider the timeframes 

applicable to the relevant threats and to 

the species’ likely responses to those 

threats in view of its life-history 

characteristics. Data that are typically 

relevant to assessing the species’ 

biological response include speciesspecific factors such as lifespan, 

reproductive rates or productivity, 

certain behaviors, and other 

demographic factors. 

In considering the foreseeable future 

as it relates to the status of the Interior 

least tern, we consider the factors 

affecting the species and historical 

abundance trends. Our period of record 

for monitoring the species and its 

associated habitat is over three decades, 

which, when combined with our 

knowledge of factors affecting the 

species, allows us to reasonably predict 

future conditions. We think it is 

reasonable to define the foreseeable 

future for the Interior least tern to be 30 

years based on analysis of these factors 

and as presented in more detail under 

Future Conditions and Species Viability, 

below. 

When the Interior least tern was listed 

as endangered in 1985, the identified 

threats (factors) influencing its status 

were the modification and loss of 

habitat and curtailment of range (Factor 

A), predation and disturbance of local 

colonies (Factor C), and the inadequacy 

of State or Federal mechanisms to 

protect its habitat at that time (Factor D). 

The following analysis, based on an 

assessment of the Interior least tern, 

evaluates these previously identified 

threats, any other threats currently 

facing the species, and those threats that 

are reasonably likely to affect the 

Interior least tern in the foreseeable 

future following the delisting and the 

removal of the Act’s protections. 

Habitat Loss and Curtailment of Range 

The primary threats identified for the 

Interior least tern in the 1985 final 

listing rule were associated with the 

destruction and modification of habitat 

due to channel engineering practices on 

large rivers of the Interior Basin (i.e., 

damming, channelization, and channel 

stabilization) (50 FR 21784, May 28, 

1985, pp. 21789–21790; Service 1990, 

pp. 22–23). Reservoirs had inundated 

hundreds of miles of historical or 

potential tern riverine habitat in many 

Mississippi River Basin drainages, and 

reduced sediment input into channels 

below dams had caused channel 

degradation, constriction, and loss of 

potential nesting habitats. 

Channelization, channel training 

structures (dikes), and bank stabilization 

in the Missouri, Mississippi, and Ohio 

Rivers prevented natural geomorphic 

response to loss of sediments, resulting 

in deepened and narrowed channels, 

and loss or terrestrialization (vegetation 

encroachment) of potential nesting 

sandbars and islands. Reservoir releases 

for hydropower, navigation, and flood 

control also were found to adversely 

affect Interior least tern populations 

surviving below these same dams 

(Service 1990, p. 22). These trends of 

habitat degradation were also expected 

to continue throughout most of the 

tern’s fragmented range (Smith and 

Stuckey 1988, entire). 

New information on the species’ 

response to the threats identified at the 

time of listing indicate that 

anthropogenic changes in some river 

channels supporting the Interior least 

tern have also benefited the Interior 

least tern in ways that may have 

compensated for historical impacts to its 

habitat. For example, in the Lower 

Mississippi River (where tern numbers 

have increased by an order of 

magnitude, and which currently 

supports more than 60 percent of the 

Interior least tern nesting population), 

channel engineering, including the 

construction of channel training dikes, 

resulted in higher sandbars as well as 

earlier and shorter spring and summer 

high water events in this portion of the 

range (Schramm 2004, pp. 306, 322; 

USACE 2013, p. 60). Such changes have 

reduced egg and chick flood-related 

mortality events, extended the nesting 

season, and increased re-nesting 

opportunities, all of which may explain 

the Interior least tern population 

increase in the Lower Mississippi River 

over the past four decades. 

Anthropogenic habitats are also now 

known to provide significant 

opportunities for Interior least tern 

nesting and recruitment. High flows in 

the Platte River have historically peaked 

after most nesting has been initiated 

within the river channel, flooding nests 

and hatchlings, and limiting re-nesting 

opportunities (Farnsworth et al. 2017, p. 

3587). Models now suggest least tern 

nesting success would only have 

occurred during 32 percent of years, an 

inadequate success rate to have 

maintained the species within the Platte 

River. It is now hypothesized that offchannel mining habitats were, and 

continue to be, critical to the success of 

the Interior least tern in the central and 

lower Platte River (Farnsworth et al. 

2017, p. 3588). Similar observations 

have been proposed for some reaches of 

the Missouri River (e.g., Jorgensen 2009, 

entire). In Texas and Colorado, foraging 

and nesting habitats created by dam 

construction have provided for Interior 

least tern colonization of arid regions 

historically unsuitable for the species 

(Service 2013, pp. 26–27). 

Although river channel engineering, 

including reservoirs, channelization, 

channel training structures, and bank 

stabilization, continues to alter the 

Interior least tern’s habitats, as outlined 

above, these habitat modifications have 

also created additional habitat 

opportunities for this species. The 

Interior least tern’s known range has 

increased significantly; the reported 

numbers of nesting Interior least terns 

have expanded by almost an order of 

magnitude from fewer than 2,000 in 

1985, to approximately 18,000 in 2005 

(Lott 2006, p. 10), and currently more 

than 480 Interior least tern colonies are 

known to occur in four major drainages 

with 16 primary subpopulations (Lott et 

al. 2013, pp. 3616–3617). Most of these 

subpopulations have been stable or 

increasing over the past two decades 

(Lott et al. 2013, p. 3620; Lott and 

Sheppard 2017a, pp. 51–52). Thus, the 

negative impacts of river channel 

engineering on the tern appear to have 

been initially overestimated. 

Loss of some historical Interior least 

tern summer nesting habitat likely 

occurred on a local or regional scale 

prior to listing; however, we have found 

no evidence that nesting habitat loss is 

currently limiting the Interior least tern 

on a rangewide scale. The Interior least 

tern continues to nest in all habitat 

types and drainages identified in 1985, 

and there is no evidence of significant 

regional decline or extirpation from any 

drainage since listing (Service 2013, p. 

10). As previously noted, the Interior 

least tern uses a variety of 

anthropogenic habitats such as 

navigation systems, reservoirs, sand 

mines, and so forth, allowing the 

Interior least tern to not only survive, 

but also to thrive in some drainages, and 

even expand its range into areas without 

historical records. 

While future conditions within some 

portion of the Interior least tern’s range 

may deteriorate due to natural or 

anthropogenic changes (for example, 

climate change may increase the 

likelihood of heavy rainfall events) or 

human demands (e.g., water extraction 

2572 Federal Register / Vol. 86, No. 8 / Wednesday, January 13, 2021 / Rules and Regulations 

or removal in the western plains), the 

wide range of the Interior least tern and 

its ability to relocate to areas with better 

conditions reduce the magnitude of any 

threat (see Effects of Climate Change, 

below). The Interior least tern is also 

well adapted to adjust to variability and 

changes in local habitat availability, 

quality, and quantity through 

metapopulation dynamics (see Habitat 

Criteria, above, for detail on 

metapopulation dynamics), enhanced 

by the species’ longevity, dispersal 

capability, and ability to re-nest (e.g., 

Lott et al. 2013, p. 3620; Lott and 

Sheppard 2017b, entire). 

Predation 

Interior least tern eggs, chicks, and 

adult individuals are susceptible to a 

wide variety of avian and terrestrial 

predators. During the 25-year 

monitoring period on the Missouri 

River, the greatest cause of egg loss has 

been predation (3 percent) (USACE 

2017b, spreadsheet line 302). On the 

Mississippi River, predation was the 

second highest cause of Interior least 

tern egg, chick, and adult mortality 

(Smith and Renken 1993, pp. 41–42). 

Interior least terns are adapted to 

avoid predation because: (1) Their eggs 

and chicks are cryptically colored to 

avoid detection; (2) chicks exhibit 

‘‘freeze’’ behavior when threatened; and 

(3) adults cooperate in alarm calls and 

attack flights on potential predators to 

the colonies (Thompson et al. 1997, p. 

11). Terns may also abandon and 

relocate colonies due to predation 

pressure (Atwood and Massey 1988, p. 

394). 

The level and effect of predation can 

be locally high and significant in some 

colonies and in some years; however, 

the Interior least tern’s adaptation to 

high levels of predation is demonstrated 

by the exponential growth of rangewide 

breeding numbers since listing in 1985. 

Interior least tern are long-lived, and 

current population trends indicate that 

sporadic local breeding failure due to 

predation or other causes is natural, and 

unlikely to be significant to the longterm stability of the rangewide 

population. 

Existing Regulatory Mechanisms 

The Interior least tern is covered by 

the Migratory Bird Treaty Act (MBTA; 

16 U.S.C. 703 et seq.). The MBTA makes 

it unlawful, at any time and by any 

means or in any manner, to pursue, 

hunt, take, capture, kill, attempt to take, 

capture, or kill, possess, offer for sale, 

sell, offer to barter, barter, offer to 

purchase, purchase, deliver for 

shipment, ship, export, import, cause to 

be shipped, exported, or imported, 

deliver for transportation, transport or 

cause to be transported, carry or cause 

to be carried, or receive for shipment, 

transportation, carriage, or export, any 

migratory bird, any part, nest, or eggs of 

any such bird, or any product, whether 

or not manufactured, which consists, or 

is composed in whole or part, of any 

such bird or any part, nest, or egg 

thereof (16 U.S.C. 703(a)). 16 U.S.C. 

704(a) states that the Secretary is 

authorized and directed to determine 

when, to what extent, if at all, and by 

what means, the take of migratory birds 

should be allowed, such as for 

educational, scientific, and recreational 

purposes, and to adopt suitable 

regulations permitting and governing 

the take. In adopting regulations, the 

Secretary is to consider such factors as 

distribution and abundance to ensure 

that any take is compatible with the 

protection of the species. 

Since the publication of the proposed 

rule to delist the Interior least tern (84 

FR 56977; October 24, 2019), the Service 

published a proposed rule to adopt a 

regulation that defines the scope of the 

MBTA as it applies to conduct resulting 

in the injury or death of migratory birds 

protected by the MBTA (85 FR 5915; 

February 3, 2020). This proposed 

regulation, if made final, will define the 

scope of the MBTA’s prohibitions to 

reach only actions directed at migratory 

birds, their nests, or their eggs, and take 

that is incidental to otherwise lawful 

activities would no longer be 

prohibited. Therefore, Federal agencies, 

industries, or private parties that have 

avoided or mitigated for incidental take 

to migratory birds due to MBTA 

prohibitions will no longer be required 

to do so. The MBTA will continue to 

protect migratory birds, their parts, 

nests, and eggs from intentional take 

and trade. We have reviewed this 

information and have evaluated the 

potential effects of these proposed 

changes on the Interior least tern. 

Incidental take is not currently a 

primary threat to the rangewide status of 

the Interior least tern, but there is the 

potential that with removal of the 

protections of the Act and the proposed 

regulation that defines the scope of the 

MBTA, incidental take may increase in 

some nesting areas. However, as noted 

herein under Habitat Criteria, above, 

USACE Divisions and Districts within 

the range of the Interior least tern have 

cooperatively modified their programs 

to minimize take of Interior least terns, 

and to provide for the long-term 

management of the nesting and foraging 

habitats across about 80 percent of the 

range of the species (USACE 2013, 

entire; 2016, entire; 2017, entire). 

USACE has also committed to continue 

consideration and management of the 

Interior least tern and its habitats 

following delisting, because maintaining 

viable populations of Interior least tern 

is in their interest, and that of all 

Federal agencies. More than 10 percent 

of the Interior least tern population 

consists of small to moderately sized 

colonies that are managed on Federal or 

State conservation lands, or under State 

and private partnerships, many of 

which are expected to continue 

management based upon environmental 

management objectives or State status 

and regulations. The Service, therefore, 

finds that should the proposed 

regulation that defines the scope of the 

MBTA be adopted, BMPs and SOPs to 

avoid incidental take of the tern will 

continue to be implemented across more 

than 90 percent of the species’ range. 

The remaining portion of the Interior 

least tern population consists of 

numerous, small, scattered, often 

ephemeral colonies nesting in habitats 

with minimal or no management. Such 

colonies without management 

commitments may be impacted by the 

proposed regulation that defines the 

scope of the MBTA. While these areas 

contribute in some small degree to 

redundancy and representation of the 

species, their success or failure within 

specific sites is not essential to the 

continued existence of the Interior least 

tern. 

In summary, incidental take is not 

currently a primary threat to the 

rangewide status of the Interior least 

tern, but there is the potential that with 

removal of the protections of the Act 

and the proposed regulation that defines 

the scope of the MBTA, incidental take 

may increase on some nesting areas. 

Any adoption of proposed changes to 

reduce the scope of the take provisions 

of the MBTA is not likely to affect 

management commitments currently in 

place, which are expected to continue 

following delisting of the Interior least 

tern, as BMPs and SOPs to avoid 

incidental take of the tern will continue 

to be implemented across more than 90 

percent of the species’ range. We also 

believe that Federal and State agencies, 

as well as private industries and 

individuals, recognize that it is in the 

public interest to minimize the impacts 

of lawful activities to Interior least tern 

and other migratory birds, and the 

Service shall continue to work with 

them to do so. 

When the Interior least tern was listed 

in 1985, the listing rule (50 FR 21784; 

May 28, 1985) noted that while the 

MBTA protected migratory birds from 

harm or harassment, it did not provide 

a mechanism to address habitat threats. 

Federal Register / Vol. 86, No. 8 / Wednesday, January 13, 2021 / Rules and Regulations 2573 

It concluded, therefore, in the absence 

of protection under the Act, the MBTA 

and other existing regulatory 

mechanisms were inadequate to prevent 

deterioration to habitats of the Interior 

least tern due to channel engineering. 

As noted previously, however, the 

effects of channel engineering on the 

species may have been more beneficial 

than detrimental, at least in some 

portions of the range (see Habitat Loss 

and Curtailment of Range, above). 

The protection, restoration, 

conservation, and management of 

ecological resources within the Interior 

least tern’s range have been broadly 

enhanced through Executive Orders and 

Federal regulations since the species 

was listed. These include provisions 

emphasizing the protection and 

restoration of ecosystem function and 

quality in compliance with existing 

Federal environmental statutes and 

regulations (e.g., under the National 

Environmental Policy Act (NEPA; 42 

U.S.C. 4321 et seq.), Clean Water Act 

(CWA), and MBTA) and endorsing 

Federal efforts to advance 

environmental goals. Water resources 

authorizations have also enhanced 

opportunities for USACE and other 

Federal agency involvement in studies 

and projects to specifically address 

objectives related to the restoration of 

ecological resources (e.g., section 1135 

of the Water Resources Development 

Act of 1986, as amended, 33 U.S.C. 2201 

et seq.) since the Interior least tern was 

listed. 

Executive Order (E.O.) 13186 

(Responsibilities of Federal Agencies to 

Protect Migratory Birds; 66 FR 3853, 

January 17, 2001) requires all Federal 

agencies to use their authorities and 

conduct their actions to promote the 

conservation of migratory bird 

populations. Actions authorized by E.O. 

13186 include: (1) Avoiding and 

minimizing adverse impacts to 

migratory birds; (2) habitat restoration 

and enhancement, and preventing 

pollution or detrimental alteration of 

migratory bird environments; (3) 

designing habitat and population 

conservation principles, measures, and 

practices into agency plans and 

planning processes; (4) promoting 

research and information exchange, 

including inventorying and monitoring; 

and (5) ensuring full consideration 

under NEPA of migratory birds such as 

the Interior least tern. These concepts 

have been incorporated by the USACE 

into its Environmental Operating 

Principles (Bridges et al. 2018, entire; 

USACE 2019, entire), and are being 

implemented within the jurisdictional 

waters inhabited by the Interior least 

tern. In the absence of the Act’s 

protections, E.O. 13186 and USACE 

operating principles and programs will 

continue to provide for protection and 

management of the Interior least tern 

and its habitats (see Habitat Criteria, 

above). 

The Civil Works Ecosystem 

Restoration Policy of 1999 (CWERP) 

(USACE ER 1165–2–501) identifies 

ecosystem restoration as one of the 

primary missions of the USACE Civil 

Works program. This policy requires a 

comprehensive examination of the 

problems contributing to ecosystem 

degradation, and the development of 

alternative means for their solution, 

with the intent of partially or fully 

reestablishing the attributes of a 

naturalistic, functioning, and selfregulating 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 nondiscretionary requirements of section 

7(a)(2) of the Act (in the Missouri, Red, 

Arkansas, and middle Mississippi 

Rivers), as well as discretionary 

components of section 7(a)(1) of the Act, 

E.O. 13186, and CWERP (in the Lower 

Mississippi River). As a result, many 

conservation measures have become 

standard operating practices (see 

Recovery Criteria, above). 

Interior least terns are listed as 

endangered in 16 of the 18 States where 

they occur: Arkansas, Colorado, Illinois, 

Indiana, Iowa, Kansas, Kentucky, 

Louisiana, Mississippi, Missouri, 

Montana, Nebraska, New Mexico, South 

Dakota, Tennessee, and Texas. Many of 

the States noted above actively manage 

Interior least terns, including seasonal 

posting to prevent disturbance of 

nesting areas (e.g., Kentucky, Kansas); 

facilitating cooperative partnerships to 

protect and manage the bird (e.g., 

Nebraska, Indiana); developing State 

management plans for the Interior least 

tern (e.g., South Dakota; Aron 2005, 

entire); conducting site-specific research 

(e.g., Mississippi); and participating in 

multi-agency planning, management, 

and monitoring programs (e.g., Missouri 

River Recovery Implementation 

Committee). 

The removal of the species from 

Federal protection might prompt some 

States to remove the Interior least tern 

from their endangered species lists. 

Regardless of Federal status, most State 

laws protect native wildlife (including 

the Interior least tern) from take and 

require State permits, in addition to 

Federal permits, to collect, harm, or 

harass migratory bird species, such as 

the Interior least tern. 

Activities that may adversely affect 

the Interior least tern and/or its habitats 

will also continue to be subject to 

numerous regulatory mechanisms, 

including the MBTA, CWA, Fish and 

Wildlife Coordination Act (FWCA; 16 

U.S.C. 661 et seq.), and NEPA. Federal 

actions to conserve and enhance Interior 

least tern habitats are now authorized by 

Executive Orders and Federal 

regulations enacted since the Interior 

least tern was listed in 1985. 

Additionally, post-delisting habitat 

management commitments by USACE 

encompass about 80 percent of the 

Interior least tern population (see 

Recovery Criteria, above). Therefore, we 

conclude that the existing regulatory 

mechanisms are adequate to protect the 

Interior least tern and address stressors 

to this species absent protections under 

the Act. 

Effects of Climate Change 

The distributions of many terrestrial 

organisms, including birds, are shifting 

in latitude or elevation in response to 

climate warming (Chen et al. 2011, pp. 

1024–1025). Although population 

declines, apparently in response to 

climate change effects, have been 

reported for long distance migrant bird 

species in both Europe and North 

America, the negative effects of climate 

change at one life or migratory stage 

may be compensated at another stage, 

e.g., by increased survival or 

reproduction on winter or breeding 

grounds (Knudson et al. 2011, p. 9). 

The ability of migratory birds to cope 

with rapid climate change effects 

depends upon the rate of their adaptive 

response to the changes (Knudson et al. 

2011, p. 12). Phenotypic plasticity (i.e., 

the ability to shift dates of migration, 

breeding, fledgling, etc.) may allow 

rapid adaptation to climate change 

effects in some species (Charmantier et 

al. 2008, entire). While there is little 

information available on Interior least 

tern phenology (life cycle events and 

how they are influenced by climate 

variation), their adaptations to habitats 

controlled by stochastic events, along 

with high mobility and use of 

anthropogenic habitats, indicate that 

they will be resilient to predicted effects 

of climate changes. 

Most climate change models predict 

increased extreme weather events (i.e., 

floods and droughts) throughout the 

Interior least tern’s breeding range 

(Lubchenco and Karl 2012, pp. 33–36). 

In the absence of clear knowledge of 

Interior least tern wintering 

2574 Federal Register / Vol. 86, No. 8 / Wednesday, January 13, 2021 / Rules and Regulations 

distributions, potential effects of climate 

change on the bird when it is away from 

its breeding range are unknown. The 

Interior least tern is well adapted to 

cope with extreme hydrologic changes, 

and its habitat and productivity are 

closely tied with stochastic weather 

events. For example, while extreme 

floods may result in annual recruitment 

loss, such events are also the primary 

factor in creating, scouring, and 

maintaining high-quality sandbars 

where Interior least terns nest (Sidle et 

al. 1992, p. 134). On the other hand, 

extreme drought events that connect 

nesting islands to the mainland and 

result in increased predation of some 

Interior least tern colonies may be offset 

by higher abundance of available 

nesting areas, increased dispersal of 

reproductive efforts, and higher local 

recruitment rates of some colonies 

during low flow periods. Rooftop 

nesting birds are susceptible to 

catastrophic recruitment failure due to 

high summer temperatures (see 

Watterson 2009, pp. 23–24; Nupp and 

Petrick 2010, pp. 5–7), and colonies on 

natural habitats may also become 

negatively affected by increasing 

summer temperatures. However, Interior 

least terns are dispersed along a wide 

latitudinal and longitudinal gradient of 

climate conditions and are unlikely to 

experience rangewide catastrophic 

recruitment failure due to high summer 

temperatures. Therefore, while Interior 

least tern colonies may be locally or 

regionally affected by changes in 

frequency and duration of extreme flood 

events and droughts, or high 

temperatures, the dispersal of the 

Interior least tern over a wide 

geographical area encompassing a 

variety of latitudinal and longitudinal 

gradients, its long life, and its ability to 

move long distances indicate the tern’s 

resilience to future patterns of predicted 

effects of climate change (Lott et al. 

2013, p. 3623). 

Habitat Loss and Fragmentation and the 

Effects of Climate Change 

Habitat destruction and fragmentation 

may reduce the likelihood of species 

surviving the effects of climate change, 

in part because smaller habitat patches 

sustain smaller populations (Hof et al. 

2011, p. 2990). Habitat fragmentation 

can also impede the dispersal ability of 

species (Hof et al. 2011, pp. 2989–2990). 

While the Interior least tern has possibly 

been affected by loss of significant 

reaches of riverine habitat such as the 

lower Missouri River and lower Red 

River, it has also increased its 

longitudinal range by exploiting 

anthropogenic habitats such as 

reservoirs in central Texas, Colorado, 

and the Rio Grande, industrial sites in 

the Wabash River, and coal mines in 

Texas. Additionally, known population 

size has also increased by an order of 

magnitude since the range became 

fragmented, and genetic studies have 

demonstrated connectivity via gene flow 

within Interior least tern populations 

and between other least tern 

populations (i.e., California least tern 

and eastern least tern; Whittier et al. 

2006, p. 179). 

Invasive salt cedar and willow 

growth, decreases in annual rainfall, 

and overuse and depletion of aquifers, 

coupled with increased human water 

demands, are occurring in the Southern 

and Northern Plains rivers, possibly to 

the future detriment of Interior least tern 

habitat and forage availability in those 

drainages. However, increases in 

impervious surfaces (e.g., artificial 

structures or compacted soils associated 

with human developments) may offset 

the negative effects of climate change in 

some watersheds, while human 

demands such as urban or industrial 

use, and irrigation, could either offset or 

exacerbate climate change effects in 

others (Caldwell et al. 2012, p. 2854). 

Based on current data, the wide 

longitudinal and latitudinal distribution 

of the Interior least tern will likely offset 

any potential localized or regional 

reduction in habitat quantity or quality, 

at least in part, by new opportunities in 

other portions of its range. 

Decline of Fish Prey 

Starvation of California least tern 

chicks has been reported due to the 

detrimental effects of El Nin ̃ 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 sublethal amounts of arsenic, mercury, 

chlorinated hydrocarbon, selenium, and 

polychlorinated biphenyl (PCBs) have 

been documented in individuals 

(Fannin and Esmoil 1993, pp. 153–157; 

Ruelle 1993, pp. 162–170; Allen et al. 

1998, pp. 358–364); however, no 

incidences of death or decreased fitness 

of Interior least terns due to 

contaminants have been reported to 

date. 

ORV impacts have been documented 

in most drainages where Interior least 

terns nest (Red, Mississippi, Arkansas, 

Ohio, and Missouri River drainages). 

However, ORV access to nesting areas 

occurs only occasionally because it is 

usually limited to situations where low 

flow conditions allow such access. 

While other threats (i.e., sandstorms, 

hail storms, heat, cold, sand spurs, fire 

ants, fireworks, airboats, etc.) may 

increase in frequency and severity in 

some portions of the Interior least tern’s 

range, most are site-specific and 

sporadic, or otherwise limited in scope. 

Interior least tern mortality occurs 

locally throughout the range due to a 

variety of natural or manmade factors. 

However, the wide distribution of the 

species, its current high numbers, its 

long life span, and its ability to relocate 

and re-nest make the Interior least tern 

resilient to occasional or periodic local 

sources of mortality, as well as potential 

effects of climate change. The increase 

in range and population size since 1985 

indicates that sources of mortality to 

localized colonies are compensated by 

these traits of resiliency, as well as by 

the potential of high recruitment rates in 

Federal Register / Vol. 86, No. 8 / Wednesday, January 13, 2021 / Rules and Regulations 2575 

other Interior least tern colonies or 

populations. 

Cumulative Effects 

Our analysis has identified no 

rangewide threats or stressors with 

significant effects to all breeding 

colonies or subpopulations. Monitoring 

data show some breeding colonies or 

subpopulation segments may decline or 

relocate due to localized stressors (e.g., 

predation, disturbance), regional 

stressors (e.g., droughts, floods), or their 

cumulative effects. Variations in colony 

locations, size, or subpopulation 

densities, however, are a characteristic 

of metapopulation dynamics, and have 

not been shown to threaten the 

rangewide status of the Interior least 

tern over an extended area. 

Additionally, the increases documented 

in the abundance and distribution of the 

Interior least tern, since it was listed in 

1985, do not support a conclusion that 

any of these stressors cumulatively pose 

a threat to the Interior least tern. 

Future Conditions and Species Viability 

Species viability, or its ability to 

survive long term, is related to its ability 

to withstand catastrophic population 

and species-level events (redundancy), 

to adapt to changing environmental 

conditions (representation), and to 

withstand disturbances of varying 

magnitude and duration (resiliency). 

The viability of a species is also 

dependent on the likelihood of new 

stressors or continued threats now and 

in the future that act to reduce a species’ 

viability. 

Redundancy of populations is needed 

to provide a margin of safety for a 

species to withstand catastrophic 

events. Current information and 

observed trends since the species was 

listed in 1985 indicate that redundancy 

of the Interior least tern is currently 

ensured by the existence of hundreds of 

breeding colonies in multiple drainages 

across a wide latitudinal and 

longitudinal range (see Current 

Distribution and Abundance, above), 

and within a variety of natural and 

anthropogenic habitats (see Nesting 

Habitat and Behavior, above). 

Representation is the ability of a 

species to adapt to both near-term and 

long-term changes in its physical (e.g., 

climate conditions, habitat conditions, 

and habitat structure) and biological 

(e.g., pathogens, competitors, and 

predators) environments. We can gauge 

representation by examining the breadth 

of genetic, phenotypic, and ecological 

diversity found within a species and its 

ability to disperse and colonize new 

areas. For the ILT, we evaluated 

representation across a breadth of 

historical ecological settings, and 

through preservation of the genetic 

diversity of the species. The Interior 

least tern was historically known from, 

and continues to occur in, two main 

natural habitat types: Large river 

sandbars and salt plains. While the salt 

plains populations were and continue to 

be historically localized in small 

portions of the Southern Plains, the 

sandbar populations occurred across a 

large latitudinal and longitudinal 

gradient, encompassing multiple river 

and stream orders, and a wide variety of 

climatic conditions. Little evidence of 

genetic structure has been found within 

the Interior least tern population 

(Draheim et al. 2010, p. 813), indicating 

high genetic connectivity between 

drainage subpopulations. There also 

appears to be high genetic connectivity 

between California, Interior, and eastern 

least terns (Draheim et al. 2010, p. 816). 

For these reasons, the Interior least tern 

appears to have adequate genetic and 

ecological representation to allow for 

adaptability to environmental changes. 

Resiliency allows a species to recover 

from periodic or occasional disturbance. 

Resilience of individual and mated terns 

is demonstrated by their ability to 

relocate and re-nest when habitat 

conditions deteriorate, or when 

disturbance by humans or predators 

becomes severe. Interior least tern 

metapopulation dynamics allow 

subpopulations and colonies to respond 

to changing habitat conditions, 

including their ability to exploit a 

variety of anthropogenic habitats that 

were not historically available (Lott et 

al. 2013, p. 3623). This resilience is 

augmented by the long life span and 

strong flight abilities of Interior least 

terns, and by the prospecting behavior 

(exploratory dispersal) of young birds 

across the landscape (Boyd and 

Thompson 1985, p. 405; Lott 2012, p. 

12; Shigeta in litt. 2014, entire). 

In addition to this review of 

redundancy, representation, and 

resiliency, which indicates a high 

likelihood of future viability for the 

Interior least tern, the Service worked 

with multiple partners to develop a 

habitat-driven, rangewide population 

model for the tern in order to consider 

status and population dynamics with 

and without continued management at 

local, regional, and rangewide scales 

(Iglay et al. 2012, entire; Lott and 

Sheppard 2017a, b, entire). The model, 

known as TernPOP (Lott and Sheppard 

2017a, b, entire), applied simulation 

analyses that were designed to explore 

stakeholder-defined scenarios of 

potential future habitat change or 

changes in management. Fifty-five 

discrete scenarios spanned the 

geographic range of the Interior least 

tern and covered the topics of (1) 

sandbar nesting habitat loss, (2) habitat 

degradation, (3) changes in predator 

management programs, and (4) 

deliberate efforts to create mid-channel 

nesting sandbars for the tern. All 55 

scenarios were evaluated relative to a 

‘‘No Action’’ scenario. Thirty replicates 

of the model were run for 30 years, and 

population growth (or decline) rates 

were calculated for each replicate (and 

then averaged across replicates) at the 

spatial scales of scenario area, 

subpopulation, drainage population, 

and the entire listed population of the 

Interior least tern. Nearly all scenarios 

of regional management or habitat loss, 

even some viewed as implausible in the 

foreseeable future (e.g., loss of 50 

percent of all sandbars on the Lower 

Mississippi River), had minimal effects 

on population growth rates calculated 

across the 30-year period at the spatial 

scales of subpopulation, population, 

and range (Lott and Sheppard 2017b, 

pp. 42–61). In most cases, severe habitat 

degradation in even relatively large 

areas was insufficient to change the 

baseline population increases observed 

during ‘‘No Action’’ scenarios to 

population declines, beyond very local 

areas. Therefore, quantitative evaluation 

of population model outputs are similar 

to and support prior qualitative 

observations that Interior least tern 

populations are resilient to many 

potential changes in habitat conditions 

across their large river network (Lott et 

al. 2013, pp. 3622–3623; Lott and 

Sheppard 2017b, pp. 59–62). 

Based upon the analysis presented 

above, the Interior least tern cannot be 

considered to be conservation-reliant, 

because it has shown to be able to adapt 

to and exploit substantial habitat 

changes throughout its range. Although 

some (10 percent) local colonies and 

peripheral population segments of the 

Interior least tern may require 

management for long-term persistence, 

their success or failure within 

individual sites is not essential to the 

continued existence of the Interior least 

tern. Viability of the Interior least tern 

is assured by its resilience, 

representation, and redundancy 

throughout the remainder of its range. 

The Interior least tern will continue to 

be conserved by habitat management 

programs in more than 80 percent of its 

range (see Habitat Criteria under 

Recovery Criteria section, above). 

Summary of Comments and 

Recommendations 

In our proposed rule published on 

October 24, 2019 (84 FR 56977), we 

requested that all interested parties 

2576 Federal Register / Vol. 86, No. 8 / Wednesday, January 13, 2021 / Rules and Regulations 

submit written comments on the 

proposal by December 23, 2019. We also 

requested public comments on the draft 

post-delisting monitoring (PDM) plan. 

We contacted appropriate Federal and 

State agencies, scientific experts and 

organizations, and other interested 

parties and invited them to comment on 

the proposal. A newspaper notice 

inviting general public comment across 

the range of the species was published 

in USA Today on October 28, 2019. We 

did not receive any requests for a public 

hearing. 

During the comment period, we 

received 25 letters or statements 

addressing the proposed action. These 

included comments from 2 peer 

reviewers, 4 State agencies in three 

States, 1 Federal agency, 1 

nongovernmental organization, and 17 

individuals. All comments are posted at 

http://www.regulations.gov under 

Docket No. FWS–R4–ES–2018–0082. 

In accordance with our policy, 

‘‘Notice of Interagency Cooperative 

Policy for Peer Review in Endangered 

Species Act Activities,’’ which was 

published on July 1, 1994 (59 FR 34270) 

and our August 22, 2016, Director’s 

Memorandum ‘‘Peer Review Process,’’, 

we solicited expert opinions from seven 

knowledgeable individuals with 

scientific expertise that included 

familiarity with this species, the 

geographic region in which it occurs, 

and conservation biology principles. We 

received responses from two peer 

reviewers. 

The peer reviewers expressed support 

for the proposed delisting and generally 

agreed with our analysis in the 

proposed rule. Both expressed concerns 

with our PDM plan, particularly the 5- 

year time period. Peer reviewer 

comments are addressed in the 

following summary and incorporated 

into the final rule as appropriate. 

We reviewed all comments for 

substantive issues and new information 

regarding the Interior least tern. 

Substantive comments we received 

during the comment period are 

addressed below and, where 

appropriate, are incorporated directly 

into this final rule. The majority of 

comments were related to the draft PDM 

plan and not the decision to delist the 

Interior least tern. 

Peer Review Comments 

(1) Comment: Both peer reviewers and 

a nongovernmental organization 

commented that the Interior least tern 

population increase and the 

achievement of the recovery goal are 

partially attributable to improved and 

increased survey efforts. One of the peer 

reviewers suggested that the Interior 

least tern abundance data used at the 

time of listing were in error, and that 

should be considered as a reason for 

delisting. 

Our Response: The reported increase 

in rangewide numbers since the Interior 

least tern was listed is partially 

attributable to increased survey efforts 

over a wider geographical range and, in 

some areas, improved survey 

techniques. This conclusion was stated 

in our 2013 5-year review of the Interior 

least tern (Service 2013) and in several 

places in our October 24, 2019, 

proposed delisting rule (84 FR 56977; 

see Population Trends under Species 

Information (p. 84 FR 56981) and 

Numerical Population Targets under 

Recovery (p. 84 FR 56982)). In addition, 

we also acknowledged the hypothesis 

that some proportion of the increase in 

rangewide least tern counts within the 

Interior Basin may be attributable to 

immigration of least terns from the Gulf 

Coast. We have retained these 

statements in those discussions in this 

final rule, and we have added an 

additional clarifying statement under 

Population Trends. 

When the Interior least tern was listed 

as endangered (50 FR 21784; May 28, 

1985), we acknowledged the difficulty 

in assessing population size of a species 

with a widely scattered distribution and 

poorly known historical trends. At that 

time, the best available information, 

including multiple surveys conducted 

over the previous decade, indicated a 

significant decline in the range of the 

Interior least tern, low population 

numbers, low reproductive success, and 

significant threats to remnant breeding 

habitats. This conclusion was endorsed, 

and listing was supported by 13 State 

wildlife or conservation agencies within 

the range of the species. While the 

Interior least tern may have been more 

abundant and widespread than 

recognized at the time the species was 

listed, the best available scientific and 

commercial information supported our 

decision to list this species as 

endangered under the Act, and there is 

no evidence that the original data used 

at that time were in error. 

(2) Comment: One peer reviewer and 

a nongovernmental organization 

commented that the Service used 

limited and flawed information 

(Jorgensen 2009, entire; Farnsworth et 

al. 2017, entire) to minimize the 

importance of the Missouri and Platte 

Rivers in the recovery of the Interior 

least tern. They stated that the Service 

overlooked that both studies were 

conceptually and analytically 

problematic, and that editorials 

identifying key shortcomings were 

subsequently peer-reviewed and 

published in the same journals (Caitlan 

et al. 2010, entire; Alexander et al. 2018, 

entire). They expressed concern that the 

use of this information reverses the 

Service’s decades-long position that 

naturally flowing and dynamic river 

systems are critically important to the 

Interior least tern, other listed species, 

and the ecosystems as a whole. 

Our Response: In our proposed 

delisting rule (84 FR 56977; October 24, 

2019) and this final rule, we have cited 

Jorgensen (2009, entire) and Farnsworth 

et al. (2017, entire), under Habitat Loss 

and Curtailment of Range, as examples 

that some anthropogenic activities are 

known to provide significant 

opportunities for Interior least tern 

nesting and recruitment, contributing to 

the population and range expansion of 

the species even within highly modified 

river systems. Neither of these 

commenters discounted the importance 

of anthropogenic habitats to tern 

recruitment in either the Platte or 

Missouri River. 

Farnsworth et al. (2017, entire) used 

historical hydrological and channel 

geometry data from a specific reach of 

the Platte River to suggest that the 

timing of seasonal flooding of low 

sandbars was not conducive to Interior 

least tern and piping plover recruitment 

success. This study also noted that 

anthropogenic habitats created by sand 

and gravel mines adjacent to the Platte 

River have been important in 

maintaining stable populations of these 

two birds within this system. Jorgensen 

(2009, entire) conducted a similar 

analysis for a short reach of the Missouri 

River in Sioux City, Iowa, concluding 

that off-site recruitment was important 

to tern and plover presence within this 

reach of the river. Caitlan et al. (2010, 

entire) and Alexander et al. (2018, 

entire) stated that the Jorgensen and 

Farnsworth et al. studies, respectively, 

were flawed and diminished the 

importance of natural river habitats to 

the ecology of the birds. 

When developing the proposed 

delisting rule, we were aware of the 

Caitlan et al. (2010, entire) and 

Alexander et al. (2018, entire) published 

editorials critiquing the Jorgensen and 

Farnsworth et al. studies. We were also 

aware that these critiques had been 

directly addressed by responses from 

the original authors clarifying semantic 

misinterpretations and including 

additional supporting information 

(Jorgensen 2010, entire; Farnsworth et 

al. 2018, entire). Both responses were 

accepted as closure of the identified 

issues within the same journals that the 

original articles and editorials were 

published. 

Federal Register / Vol. 86, No. 8 / Wednesday, January 13, 2021 / Rules and Regulations 2577 

We have not used this information 

(Jorgensen 2009, entire; Farnsworth et 

al. 2017, entire) to discount or diminish 

the importance of natural riverine 

habitats to the tern or the ecosystem, but 

rather as supporting evidence of the 

resiliency of the Interior least tern 

relative to its ability to adapt to and 

exploit some anthropogenic changes to 

its habitats. Natural and anthropogenic 

habitats in both the Platte and Missouri 

Rivers continue to be important 

components of the greater Interior least 

tern metapopulation. 

(3) Comment: In their critique of the 

use of Farnsworth et al. (2017, entire) 

and Jorgensen (2009, entire), one peer 

reviewer and a nongovernmental 

organization stated that the Service did 

not consider the role of metapopulation 

dynamics in the use of anthropogenic 

habitats by Interior least terns in the 

Platte River. They noted that off-river 

anthropogenic habitats such as sand and 

gravel mines may not be sustainable and 

evolving mining practices may reduce 

the amount and quality of such habitats 

in the future. 

Our Response: Under Habitat Criteria 

and elsewhere in the proposed delisting 

rule (84 FR 56977; October 24, 2019) 

and this final rule, the Service discusses 

the role and importance of 

metapopulation dynamics in the current 

and future distribution and resilience of 

the Interior least tern. We find the 

information presented in the referenced 

studies is important to understanding 

the role of past and future habitat 

conditions in the Platte and Missouri 

Rivers to the metapopulation dynamics 

of the Interior least tern. 

Metapopulation dynamics allow 

species to exploit habitats that may 

change rapidly in abundance and/or 

quality and aid the re-establishment of 

extirpated populations. Both natural 

and anthropogenic least tern nesting 

habitats can be transitional in 

availability or quality. Some breeding 

colonies or subpopulation segments 

have declined or relocated due to 

localized stressors (e.g., predation, 

disturbance), regional stressors (e.g., 

droughts, floods), habitat changes (e.g., 

vegetation encroachment, reservoir 

management, mine closures), or their 

cumulative effects (Kirsch and Sidle 

1999, p. 475; Service 2013, pp. 13–27). 

Resulting variations in tern colony 

locations, sizes, or subpopulation 

densities are a characteristic of 

metapopulation dynamics, and such 

declines have been offset by increases in 

other colonies or population segments 

(Lott and Sheppard 2017a, pp. 50–52). 

While future changes in mining 

practices within the Platte River 

drainage may affect their use by Interior 

least terns, metapopulation dynamics 

allow the birds to find and use other 

suitable habitats within or outside of the 

drainage for nesting. 

(4) Comment: One peer reviewer and 

a nongovernmental organization 

commented that the Service failed to 

reference or acknowledge changes to the 

Migratory Bird Treaty Act (MBTA) 

directed by the M-Opinion and 

encouraged the Service to evaluate the 

consequences relative to the Interior 

least tern. 

Our Response: After the publication 

of our October 24, 2019, proposed 

delisting rule, the Service published a 

proposed rule to adopt a regulation that 

defines the scope of the MBTA as it 

applies to conduct resulting in the 

injury or death of migratory birds 

protected by the MBTA (85 FR 5915; 

February 3, 2020). This proposed 

regulation, if made final, will define the 

scope of the MBTA’s prohibitions to 

reach only actions directed at migratory 

birds, their nests, or their eggs, and take 

that is incidental to otherwise lawful 

activities would no longer be 

prohibited. This position is consistent 

with the Solicitor’s Opinion M–37050, 

The Migratory Bird Treaty Act Does Not 

Prohibit Incidental Take, issued 

December 22, 2017. We have reviewed 

this information and have evaluated the 

potential effects of these proposed 

changes on the Interior least tern. Our 

analysis is presented above under 

Existing Regulatory Mechanisms. In 

summary, incidental take is not 

currently a primary threat to the 

rangewide status of the Interior least 

tern, but there is the potential that with 

removal of the protections of the Act 

and these proposed regulatory changes 

defining the scope of the MBTA, 

incidental take may increase in some 

nesting areas. However, as described 

above, should the proposed changes be 

adopted, BMPs and SOPs to avoid 

incidental take of the tern will continue 

to be implemented across more than 90 

percent of the species’ range (e.g., 

USACE 2013, entire; 2016, entire; 2017, 

entire; see Habitat Criteria, above). 

Therefore, the adoption of proposed 

regulatory changes to limit the scope of 

the take provisions of the MBTA are not 

likely to affect management 

commitments currently in place, which 

are expected to continue following 

delisting of the Interior least tern. 

(5) Comment: Both peer reviewers, 

along with the States of Oklahoma and 

Colorado, a nongovernmental 

conservation agency, and several other 

public commenters stated that the 

duration of PDM plan is inadequate and 

recommended modifying the duration to 

include monitoring every third year for 

a period of 15 years. They noted that the 

Interior least tern may have a lifespan of 

15 to 20 years; therefore, limiting PDM 

to 5 years may not be sufficient to track 

population fluctuations after delisting. 

Our Response: Following delisting, 

the Act requires us to effectively 

implement a monitoring system for a 

minimum of 5 years in cooperation with 

the States that are within the range of 

the Interior least tern. To fulfill the PDM 

requirement, we developed a draft PDM 

plan for the Interior least tern and 

coordinated review of the plan with the 

State agencies, USACE Districts and 

Divisions, other Federal agencies, and 

various nongovernmental organizations. 

We acknowledge that sustaining PDM 

efforts can be challenging and subject to 

competing priorities for available 

resources. Nonetheless, we designed the 

draft PDM plan that was realistic given 

limited resources. However, given the 

comments we received on the duration 

of the draft PDM plan, we will continue 

to work with our conservation partners 

to ensure development and 

implementation of an effective, final 

PDM plan, with an appropriate 

duration, for the Interior least tern. 

While section 4(g)(1) of the Act 

requires us to implement a system in 

cooperation with the States to 

effectively monitor the status of any 

species that have been recovered and 

removed from the List(s), it does not 

require the development of a formal 

PDM plan prior to removing the species 

from the List, or at any point. The 

Service and States have wide latitude in 

implementation of this provision. In the 

absence of a final PDM plan, 

monitoring, with surveys continuing in 

2021, is expected to continue for more 

than 80 percent of the Interior least tern 

population due to management 

commitments by the USACE and the 

States. However, we generally desire to 

follow a written planning document to 

provide for the effective implementation 

of section 4(g), and we intend to do so 

here. We will notify the public of the 

final PDM plan on our website, https:// 

www.fws.gov/mississippiES/, after 

coordination with our partners and 

when it becomes available. 

(6) Comment: One peer reviewer 

expressed concern that the potential of 

increased frequency and duration of 

flooding due to climate change was not 

addressed in the PDM plan. This peer 

reviewer also believes that there should 

be a mechanism in the plan for the 

Service to intervene if there are 

continued or recurrent flooding events. 

Our Response: The purpose of PDM is 

to track the post-delisting status of the 

Interior least tern to ensure that it 

remains secure from risk of extinction 

2578 Federal Register / Vol. 86, No. 8 / Wednesday, January 13, 2021 / Rules and Regulations 

following removal from the List. While 

the draft PDM plan does not identify a 

specific mechanism to intervene 

following flood events, it identifies 

actions that may be taken should 

monitoring indicate a substantial 

decline in the Interior least tern’s 

population numbers or distribution. 

These actions include meeting with 

conservation partners, extending the 

monitoring period, modifying 

monitoring practices, initiating a 

rangewide status assessment, or relisting 

the Interior least tern, if warranted. As 

stated above under Our Response to (5) 

Comment, we will continue to work 

with our conservation partners to 

develop and implement an effective, 

final PDM plan for the Interior least tern 

that includes an appropriate duration 

and purpose to detect trends. 

(7) Comment: One peer reviewer 

asserted that in parts of the species’ 

range some degree of human 

intervention will be needed for 

continued success and that an 

assessment of habitat management 

should be part of the PDM plan. 

Our Response: The Interior least tern’s 

adaptation to, and exploitation of, 

anthropogenic habitats over the past 

several decades indicate that the species 

is no longer considered conservationreliant and is recovered. However, we 

assessed the adequacy of habitat 

management commitments relative to 

recovery of the tern in our proposed 

delisting rule (84 FR 56977; October 24, 

2019) and this final rule, finding that 

conservation actions and management 

by multiple conservation partners, most 

principally the USACE (e.g., USACE 

2013, entire; 2016, entire; 2017, entire), 

will continue following delisting. Many 

conservation programs and 

commitments incorporate components 

of adaptive management, which provide 

for periodic assessment of habitat 

management actions relative to effects 

on the Interior least tern (see Habitat 

Criteria, above, under Recovery 

Criteria). As noted in the draft PDM and 

the proposed delisting rule, 

management commitments by USACE 

alone currently encompass about 80 

percent of the Interior least tern 

breeding population, including large 

portions of the Mississippi, Red, 

Arkansas, and Missouri Rivers. 

As stated above under Our Response 

to (5) Comment, we will continue to 

work with our conservation partners to 

develop and implement an effective, 

final PDM plan for the Interior least tern 

that includes an appropriate duration 

and purpose to detect trends. 

(8) Comment: One peer reviewer 

expressed concerns that the inclusion of 

the Arkansas River as part of the 

Mississippi River subpopulation in the 

PDM plan dilutes the importance of the 

Arkansas River. This reviewer suggested 

subdividing the four major 

subpopulations to ensure that recovery 

is truly rangewide. 

Our Response: This comment refers to 

a map under ‘‘Methods’’ in the draft 

PDM plan showing the wide 

distribution of the tern, as well as the 

multiple habitats used as nesting areas. 

In the referenced map, Interior least tern 

subpopulations were defined by Lott et 

al. (2013, entire) based upon observed 

least tern dispersal movements relative 

to distance between nesting colonies. 

Based upon this analysis, the Lower 

Mississippi, Arkansas, Cimarron, and 

Canadian Rivers constitute one of four 

relatively continuous subpopulations. 

The identification of subpopulations 

does not reduce the importance of any 

geographical portion of a species’ range, 

particularly as movement and 

population numbers relate to 

metapopulation dynamics. 

Additionally, the USACE Southwestern 

Division (SWD) Districts, who monitors 

the Arkansas River along with portions 

of the Red and Canadian Rivers, has 

committed to continue this monitoring 

post-delisting as appropriations allow. 

(9) Comment: One peer reviewer 

expressed concern that the PDM plan 

does not assess productivity of Interior 

least terns. 

Our Response: Within the Interior 

least tern metapopulation, 

measurements of productivity within 

individual colonies may be masked by 

movements between colonies or even 

drainages, depending upon habitat 

conditions. Attempts have been made to 

assess tern productivity at various 

locations (e.g., some Missouri River 

colony clusters, Platte River, Mississippi 

River sites, Wabash industrial sites); 

however, annual tern counts show little 

relation to previous year measurements 

of nest success, fledgling ratios, or 

annual recruitment. Therefore, we did 

not include assessment of Interior least 

tern productivity in the draft PDM plan. 

As noted in the draft PDM plan, 

rangewide PDM of the Interior least tern 

relies upon continuation of existing 

monitoring programs throughout the 

birds’ extensive range. Monitoring 

methods have been, and will continue 

to be, at the discretion of each program, 

provided that they meet the minimum 

survey requirements in the PDM plan to 

record the location of breeding colonies 

(two or more birds) and make counts of 

adults present at the time the colonies 

are surveyed. Any additional efforts are 

at the discretion of the local program. 

(10) Comment: One peer reviewer 

characterized the PDM plan as 

providing a 10,000 bird ‘‘population 

target’’ and indicated such an approach 

appears to be arbitrary. The peer 

reviewer suggested that the Service 

might identify a percentage decline, as 

opposed to a specific number, to initiate 

further monitoring, or that the 

population model developed by the 

Service and the USACE (TernPOP) 

might be used to generate a target 

number based on chance of long-term 

persistence. 

Our Response: The 10,000 birds 

referenced in the draft PDM plan is not 

meant to be a population target, but 

rather, a threshold to review 

significance, methods, and potential 

threats with States and other 

collaborators before numbers might fall 

below the recovery objective (7,000 

birds). Tern counts are not static or 

consistent, and there has always been 

high variability (15 percent or more) 

between annual counts at local, 

regional, and rangewide population 

levels over the period of record (35 

years). Even so, the rangewide counts, 

as well as some subpopulations and 

colonies, have shown a general 

increasing trend over this same period. 

As we noted in the proposed delisting 

rule (84 FR 56977; October 24, 2019) 

under Future Conditions and Species 

Viability, we developed TernPOP as a 

habitat-driven, rangewide population 

model to consider scenarios of status 

and population dynamics at multiple 

scales, with and without management, 

and with different scenarios of habitat 

loss. TernPOP is not designed to 

generate any target number based on 

long-term persistence. Local and 

regional Interior least tern numbers and 

success are generally driven by habitat. 

Nearly all scenarios of regional 

management or habitat loss had 

minimal effects on population growth 

rates calculated across a 30-year period 

at the spatial scales of subpopulation, 

population, and range. 

(11) Comment: One peer reviewer 

expressed that the PDM plan should 

identify an action plan to quickly 

respond to any decline in numbers or 

productivity of the Interior least tern. 

The quick action plan should assess the 

causes of decline and direct resources 

for recovery. 

Our Response: Because we have a 35- 

year record of increase for the tern, the 

objective of the draft PDM plan is to 

ensure that populations of the species 

do not decline once the Act’s 

protections have been removed. As 

noted under Our Response to (10) 

Comment, above, we identified a 

conservative rangewide count number 

to initiate inquiry with Federal, State, 

and other collaborators into whether 

Federal Register / Vol. 86, No. 8 / Wednesday, January 13, 2021 / Rules and Regulations 2579 

any observed decline in tern counts is 

real or an annual variation, and/or to 

investigate any potential causes of 

decline. 

State Comments 

Section 4(b)(5)(A)(ii) of the Act states 

that the Secretary must give actual 

notice of a proposed regulation under 

section 4(a) to the State agency in each 

State in which the species is believed to 

occur and invite the comments of such 

agency. Section 4(i) of the Act directs 

that the Secretary will submit to the 

State agency a written justification for 

his or her failure to adopt regulations 

consistent with the agency’s comments 

or petition. We solicited comments from 

the 18 States within the summer 

breeding range of the Interior least tern. 

The States of Oklahoma, Colorado, and 

New Mexico responded with 

concurrence for the delisting action; 

however, the States of Oklahoma and 

Colorado expressed concern that the 

duration of PDM was inadequate to 

determine trends in this long-lived 

species (see Our Response to Comment 

(5), above). 

Other Public Comments 

(12) Comment: One commenter 

observed that, while the Interior least 

tern may warrant delisting due to its 

population increase along the 

Mississippi River, its numbers have 

continued to decline in most other river 

systems within its range. 

Our Response: Annual changes in 

relative abundance of colonies or 

subpopulations of a metapopulation 

may fluctuate widely on an annual 

basis. In the proposed delisting rule (84 

FR 56977; October 24, 2019), we 

presented information that most Interior 

least tern subpopulations have been 

stable or increasing over the past two 

decades. While the Mississippi River 

has experienced the greatest increase in 

Interior least tern nesting population 

size, the analysis of 15 river system 

subpopulations with 20 or more years of 

monitoring data indicates that over that 

period of record, 10 experienced 

increases, 4 remained relatively stable, 

and only 1 (below Ft. Peck Dam) 

experienced a significant decline. 

(13) Comment: Several commenters 

noted that the Interior least tern and its 

habitats remain vulnerable to climate 

change; one commenter was concerned 

about sea level rise and another stated 

that the species should remain 

threatened due to flooding associated 

with climate change. 

Our Response: Because the Interior 

least tern nests within the Interior Basin 

remote from coastal areas, inundation 

by sea level rise is not a concern to its 

breeding range. We considered other 

potential effects of climate change in the 

proposed delisting rule (84 FR 56977; 

October 24, 2019) and this final rule 

under Effects of Climate Change, 

including the potential of increased 

flooding frequency. We conclude that 

the wide range of the Interior least tern 

(16 degrees of longitude; 18 degrees of 

latitude), its metapopulation dynamics, 

and its ability to relocate and exploit a 

wide variety of habitats reduces the 

magnitude of such threats. The response 

of the Interior least tern to any specific 

flood event may not be readily observed, 

and while such events may suppress 

local or regional reproduction and 

recruitment in some years, or shift 

reproduction and recruitment to other 

areas, major flood events also reset 

habitats and may result in increased 

numbers of terns in subsequent years. 

For example, Missouri River flood years 

are generally followed by improved 

nesting habitats supporting large 

increases in tern numbers and 

recruitment in subsequent years. 

Summary of Changes From the 

Proposed Rule 

We considered all comments and 

information we received during the 

comment period for the proposed rule to 

delist the Interior least tern (84 FR 

56977; October 24, 2019). We made 

minor editorial changes throughout the 

rule and added additional information 

to clarify our understanding of 

‘‘foreseeable future,’’ which published 

in an August 27, 2019, final rule (84 FR 

45020) (see 50 CFR 424.11(d)). These 

recent revisions did not significantly 

modify the Service’s interpretation of 

foreseeable future, but rather, we 

codified a framework that sets forth how 

we will determine what constitutes the 

foreseeable future based on our longstanding practice. We have added a 

statement under Population Trends 

regarding the role of increased survey 

effort and the geographical extent of the 

area surveyed in the observed 

population increase since listing. Lastly, 

we also added information about how 

we considered the potential 

consequences to the Interior least tern of 

the February 3, 2020 (85 FR 5915), 

proposed rule to define the scope of the 

MBTA under Existing Regulatory 

Mechanisms, above. 

Determination of Interior Least Tern 

Status 

Section 4 of the Act (16 U.S.C. 1533) 

and its implementing regulations (50 

CFR part 424) set forth the procedures 

for determining whether a species meets 

the definition of ‘‘endangered species’’ 

or ‘‘threatened species.’’ The Act defines 

endangered species as a species that is 

‘‘in danger of extinction throughout all 

or a significant portion of its range,’’ and 

a threatened species as a species that is 

‘‘likely to become an endangered 

species within the foreseeable future 

throughout all or a significant portion of 

its range.’’ For a more detailed 

discussion on the factors considered 

when determining whether a species 

meets the definition of an endangered 

species or a threatened species and our 

analysis on how we determine the 

foreseeable future in making these 

decisions, please see Summary of 

Factors Affecting the Species. 

Status Throughout All of Its Range 

Since its 1985 listing under the Act, 

the Interior least tern has shown an 

ability to adapt to changing 

environmental conditions caused by 

both human and natural disturbances. 

The Interior least tern nesting 

population encompasses hundreds of 

colonies in 18 States throughout the 

Interior Basin, from Montana southward 

through North Dakota, South Dakota, 

Nebraska, Colorado, Iowa, Kansas, 

Missouri, Illinois, Indiana, and 

Kentucky to eastern New Mexico, 

Oklahoma, Arkansas, Tennessee, Texas, 

Louisiana, and Mississippi (see 

supplemental documents at https://

www.regulations.gov under Docket No. 

FWS–R4–ES–2018–0082). Therefore, the 

Interior least tern is highly redundant 

and resistant to future catastrophic 

events. Its representation is ensured by 

its continued occurrence within all 

known historical habitats (i.e., Salt 

Plains, multiple river and stream orders) 

across a large latitudinal and 

longitudinal gradient and a wide variety 

of climatic conditions. Interior least tern 

resilience is demonstrated by 

metapopulation dynamics, by its ability 

to adapt to multiple natural and 

anthropogenic conditions, and by 

evidence of high genetic connectivity 

between drainage subpopulations. 

Because the Interior least tern has been 

considered to be increasing and selfsustaining since listing (35 years), and 

consists of a relatively large number of 

individuals with demonstrated high 

redundancy, representation, and 

resilience, we expect it to remain viable 

into the future. 

We have carefully assessed the best 

scientific and commercial information 

available regarding the threats faced by 

the Interior least tern. Our analysis 

found an increase in the abundance, 

number of breeding sites, and range of 

the Interior least tern; resiliency to 

existing and potential threats; active 

habitat management and the 

implementation of beneficial 

2580 Federal Register / Vol. 86, No. 8 / Wednesday, January 13, 2021 / Rules and Regulations 

management practices; and changes in 

existing regulatory mechanisms that are 

protective of migratory bird habitats. 

Known threats at the time of listing— 

habitat loss and curtailment of range, 

and predation—have been reduced or 

adequately managed, and we have 

analyzed possible new threats related to 

climate change and determined that 

they are not significant threats to the 

Interior least tern now or within the 

foreseeable future. Existing State and 

Federal regulatory mechanisms are 

adequate to protect the tern. The net 

effect of current and predictable future 

stressors to the species, after 

considering applicable conservation 

measures and the existing regulatory 

mechanisms, are not sufficient to cause 

the Interior least tern to be in danger of 

extinction now or likely to become so 

within the foreseeable future throughout 

its range. We find that the Interior least 

tern has recovered so that it no longer 

meets the definition of an endangered 

species or a threatened species under 

the Act throughout its range. 

Status Throughout a Significant Portion 

of Its Range 

Under the Act and our implementing 

regulations, a species may warrant 

listing if it is in danger of extinction or 

likely to become so in the foreseeable 

future throughout all or a significant 

portion of its range. Having determined 

that the Interior least tern is not in 

danger of extinction or likely to become 

so in the foreseeable future throughout 

all of its range, we now consider 

whether it may be in danger of 

extinction or likely to become so in the 

foreseeable future in a significant 

portion of its range—that is, whether 

there is any portion of the species’ range 

for which it is true that both (1) the 

portion is significant; and (2) the species 

is in danger of extinction now or likely 

to become so in the foreseeable future in 

that portion. Depending on the case, it 

might be more efficient for us to address 

the ‘‘significance’’ question or the 

‘‘status’’ question first. We can choose to 

address either question first. Regardless 

of which question we address first, if we 

reach a negative answer with respect to 

the first question that we address, we do 

not need to evaluate the other question 

for that portion of the species’ range. 

In undertaking this analysis for the 

Interior least tern, we chose to address 

the status question first—we considered 

information pertaining to the geographic 

distribution of both the species and the 

threats that the species faces to identify 

any portions of the range where the 

species is endangered or threatened. We 

considered whether any of the threats 

acting on the Interior least tern are 

geographically concentrated in any 

portion of the species’ range at a 

biologically meaningful scale. 

We examined the following threats: 

Habitat loss, curtailment of range, 

predation, and inadequacy of regulatory 

mechanisms, including cumulative 

effects. We found that while some 

colonies may be locally affected by 

future threats, these threats are not 

geographically concentrated. This 

finding is supported by a habitat driven, 

rangewide population model (TernPOP; 

Lott and Sheppard 2017a, b, entire), 

which considered 55 discrete scenarios 

of potential future habitat change 

(threats) or changes in management at 

local, regional, and rangewide scales, 

and covered the topics of (1) sandbar 

nesting habitat loss, (2) habitat 

degradation, (3) changes in predator 

management programs, and (4) 

deliberate efforts to create mid-channel 

nesting sandbars for the tern (see Future 

Conditions and Species Viability, 

above). We found no concentration of 

threats in any portion of the Interior 

least tern’s range at a biologically 

meaningful scale. Thus, there are no 

portions of the species’ range where the 

species has a different status from its 

rangewide status. Therefore, no portions 

of the species’ range provides a basis for 

determining that the species is in danger 

of extinction or likely to become an 

endangered species in the foreseeable 

future throughout a significant portion 

of its range. This approach is consistent 

with the courts’ holdings in Desert 

Survivors v. Department of the Interior, 

No. 16-cv-01165–JCS, 2018 WL 4053447 

(N.D. Cal. Aug. 24, 2018), and Center for 

Biological Diversity v. Jewell, 248 F. 

Supp. 3d, 946, 959 (D. Ariz. 2017). 

Conclusion and Determination of Status 

Our review of the best available 

scientific and commercial information 

indicates that the Interior least tern is 

not in danger of extinction nor likely to 

become an endangered species within 

the foreseeable future throughout all or 

a significant portion of its range. 

Therefore, we find that the Interior least 

tern does not meet the definition of an 

endangered species or a threatened 

species under the Act. 

Effects of This Rule 

This rule revises 50 CFR 17.11(h) by 

removing the Interior least tern from the 

Federal List of Endangered and 

Threatened Wildlife. On the effective 

date of this rule (see DATES, above), the 

protections provided by the Act, 

particularly through sections 7 and 9, no 

longer apply to the Interior least tern. 

Federal agencies are no longer required 

to consult with the Service under 

section 7 of the Act in the event that 

activities they authorize, fund, or carry 

out may affect the Interior least tern. 

There is no critical habitat designated 

for the Interior least tern; therefore, this 

rule does not affect 50 CFR 17.95. 

Removal of the Interior least tern from 

the List of Endangered and Threatened 

Wildlife does not affect the protection 

given to all migratory bird species under 

the MBTA. 

Post-Delisting Monitoring 

Section 4(g)(1) of the Act requires us 

to monitor for not less than 5 years, the 

status of all species that are delisted due 

to recovery. Post-delisting monitoring 

(PDM) refers to activities undertaken to 

verify that a species delisted due to 

recovery remains secure from the risk of 

extinction after the protections of the 

Act no longer apply. The primary goal 

of PDM is to monitor the species to 

ensure that its status does not 

deteriorate, and if a decline is detected, 

to take measures to halt the decline so 

that proposing it as endangered or 

threatened is not again needed. If at any 

time during the monitoring period, data 

indicate that protective status under the 

Act should be reinstated, we can initiate 

listing procedures, including, if 

appropriate, emergency listing under 

section 4(b)(7) of the Act. Section 4(g) of 

the Act explicitly requires us to 

cooperate with the States in 

development and implementation of 

PDM programs, but we remain 

responsible for compliance with section 

4(g) of the Act and, therefore, must 

remain actively engaged in all phases of 

PDM. We also seek active participation 

of other entities that are expected to 

assume responsibilities for the species’ 

conservation post-delisting. At the 

conclusion of the monitoring period, we 

will review all available information to 

determine if relisting, the continuation 

of monitoring, or the termination of 

monitoring is appropriate. 

Draft Post-Delisting Monitoring Plan 

Overview 

While section 4(g)(1) of the Act 

requires us to implement a system in 

cooperation with the States to 

effectively monitor the status of any 

species that have been recovered and 

removed from the List(s), it does not 

require the development of a formal 

PDM plan prior to removing the species 

from the List, or at any point. The 

Service and States have wide latitude in 

implementation of this provision. 

However, we generally desire to follow 

a written planning document to provide 

for the effective implementation of 

section 4(g), and we intend to do so 

here. To fulfill the requirement to 

Federal Register / Vol. 86, No. 8 / Wednesday, January 13, 2021 / Rules and Regulations 2581 

monitor for not less than 5 years, we 

developed a draft PDM plan for the 

Interior least tern and coordinated 

review of the plan with the State 

agencies, USACE Districts and 

Divisions, other Federal agencies, and 

various nongovernmental organizations. 

We published a notice of availability of 

a draft PDM plan with the proposed 

delisting rule (84 FR 56977; October 24, 

2019). However, given the comments we 

received on the duration of the draft 

PDM plan, we will continue to work 

with our conservation partners to 

develop and implement an effective, 

final PDM plan, with an appropriate 

duration, for Interior least tern. Existing 

monitoring programs over more than 80 

percent of the species’ range (e.g., 

USACE 2013, 2016, 2018) are 

committed to continue monitoring 

following delisting as we coordinate 

planning, and in the absence of a final 

PDM plan, periodic monitoring, with 

surveys in 2021, is expected to continue 

into the indefinite future due to 

management commitments by the 

USACE and the States, regardless of the 

tern’s status under the Act. However, we 

generally desire to follow a written 

planning document to provide for the 

effective implementation of section 4(g), 

and we intend to do so here. We will 

notify the public of the final PDM plan 

on our website, https://www.fws.gov/ 

mississippiES/, after coordination with 

our partners and when it becomes 

available. The current draft PDM plan is 

available at https://www.fws.gov/ 

mississippiES/. 

Required Determinations 

National Environmental Policy Act 

We have determined that 

environmental assessments and 

environmental impact statements, as 

defined under the authority of the 

National Environmental Policy Act 

(NEPA; 42 U.S.C. 4321 et seq.), need not 

be prepared in connection with 

determining and implementing a 

species’ listing status under the 

Endangered Species Act. We published 

a notice outlining our reasons for this 

determination in the Federal Register 

on October 25, 1983 (48 FR 49244). 

Government-to-Government 

Relationship With Tribes 

In accordance with the President’s 

memorandum of April 29, 1994 

(Government-to-Government Relations 

with Native American Tribal 

Governments; 59 FR 22951), Executive 

Order 13175 (Consultation and 

Coordination with Indian Tribal 

Governments), and the Department of 

the Interior’s manual at 512 DM 2, we 

readily acknowledge our responsibility 

to communicate meaningfully with 

recognized Federal Tribes on a 

government-to-government basis. In 

accordance with Secretarial Order 3206 

of June 5, 1997 (American Indian Tribal 

Rights, Federal-Tribal Trust 

Responsibilities, and the Endangered 

Species Act), we readily acknowledge 

our responsibilities to work directly 

with Tribes in developing programs for 

healthy ecosystems, to acknowledge that 

Tribal lands are not subject to the same 

controls as Federal public lands, to 

remain sensitive to Indian culture, and 

to make information available to Tribes. 

We do not believe that any Tribes will 

be affected by this rule. However, we 

contacted each of the Tribes within the 

range of the Interior least tern and 

requested their input on the proposed 

delisting rule and draft PDM. We did 

not receive any comments from them. 

References Cited 

A complete list of references cited is 

available on http://www.regulations.gov 

under Docket Number FWS–R4–ES– 

2018–0082, or upon request from the 

Field Supervisor, Mississippi Ecological 

Services Field Office (see FOR FURTHER

INFORMATION CONTACT). 

Author 

The primary author of this rule is Paul 

Hartfield, Mississippi Ecological 

Services Field Office (see FOR FURTHER

INFORMATION CONTACT). 

List of Subjects in 50 CFR Part 17 

Endangered and threatened species, 

Exports, Imports, Reporting and 

recordkeeping requirements, 

Transportation. 

Regulation Promulgation 

Accordingly, we amend part 17, 

subchapter B of chapter I, title 50 of the 

Code of Federal Regulations, as set forth 

below: 

PART 17—ENDANGERED AND 

THREATENED WILDLIFE AND PLANTS 

■ 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. 

§ 17.11 [Amended] 

■ 2. Amend § 17.11(h) by removing the 

entry for ‘‘Tern, least [Interior DPS]’’ 

under ‘‘Birds’’ from the List of 

Endangered and Threatened Wildlife. 

Signing Authority 

The Director, U.S. Fish and Wildlife 

Service, approved this document and 

authorized the undersigned to sign and 

submit the document to the Office of the 

Federal Register for publication 

electronically as an official document of 

the U.S. Fish and Wildlife Service. 

Aurelia Skipwith, Director, U.S. Fish 

and Wildlife Service, approved this 

document on November 19, 2020, for 

publication. 

Dated: November 19, 2020. 

Madonna Baucum, 

Regulations and Policy Chief, Division of 

Policy, Economics, Risk Management, and 

Analytics, Joint Administrative Operations, 

U.S. Fish and Wildlife Service. 

[FR Doc. 2020–28192 Filed 1–12–21; 8:45 am] 

BILLING CODE 4333–15–P