Endangered and Threatened Wildlife and Plants; Removing the Black-Capped Vireo From the Federal List of Endangered and Threatened Wildlife, 16228-16242 [2018-07350]

Agencies

• Fish and Wildlife Service
• DEPARTMENT OF THE INTERIOR

[Federal Register Volume 83, Number 73 (Monday, April 16, 2018)]
[Rules and Regulations]
[Pages 16228-16242]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2018-07350]


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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[Docket No. FWS-R2-ES-2016-0110; FXES11130900000 178 FF09E42000]
RIN 1018-BB79


Endangered and Threatened Wildlife and Plants; Removing the 
Black-Capped Vireo From the Federal List of Endangered and Threatened 
Wildlife

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Final rule.

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SUMMARY: Under the authority of the Endangered Species Act of 1973 
(Act), as amended, we, the U.S. Fish and Wildlife Service (Service), 
remove the black-capped vireo (Vireo atricapilla, listed as Vireo 
atricapillus) 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 information, 
which indicates that the threats to this species have been reduced or 
managed to the point that the species has recovered and no longer meets 
the definition of endangered or threatened under the Act.

DATES: This rule is effective May 16, 2018.

ADDRESSES: This final rule is available on the internet at https://www.regulations.gov under Docket No. FWS-R2-ES-2016-0110 and at https://www.fws.gov/southwest/es/arlingtontexas/. Comments and materials we 
received, as well as supporting documentation we used in preparing this 
rule, are available for public inspection at https://www.regulations.gov. Comments, materials, and documentation that we 
considered in this rulemaking will be available by appointment, during 
normal business hours, at: U.S. Fish and Wildlife Service, Arlington 
Ecological Services Field Office, 2005 NE Green Oaks Blvd., Arlington, 
TX 76006; telephone 817-277-1100; facsimile 817-277-1129; 
[email protected].

FOR FURTHER INFORMATION CONTACT: Debra Bills, Field Supervisor, U.S. 
Fish and Wildlife Service, Arlington Ecological Services Field Office, 
2005 NE Green Oaks Blvd., Suite 140, Arlington, TX 76006; telephone 
817-277-1100; or facsimile 817-277-1129. Persons 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 Endangered Species Act, a 
species may be removed (delisted) from the Federal List of Endangered 
and Threatened Wildlife if it is determined it has recovered and is no 
longer endangered or threatened. Delisting can only be completed by 
issuing a rule.
    This rule removes the black-capped vireo (Vireo atricapilla, listed 
as Vireo atricapillus) from the Federal List of Endangered and 
Threatened Wildlife.
    The basis for our action. Under the Endangered Species Act, we 
determine that a species is an endangered or 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 in 
delisting a species. We may delist a species if the best scientific and 
commercial data indicate the species is neither endangered nor 
threatened for one or more of the following reasons: (1) The species is 
extinct; (2) the species has recovered and is no longer threatened or 
endangered; or (3) the original scientific data used at the time the 
species was classified were in error. We have determined that the 
primary threats to the black-capped vireo have been reduced or managed 
to the point that the species is recovered.
    Peer review and public comment. We completed a Species Status 
Assessment (SSA) to evaluate the species' needs, current conditions, 
and future conditions to support our proposed rule. We sought comments 
from independent specialists to ensure that our determination is based 
on scientifically sound data, assumptions, and analyses. We invited 
these peer reviewers to comment on the SSA report. We considered all 
comments and information we received during the comment period on the 
proposed rule to delist the black-capped vireo when finalizing our SSA 
report and this final rule.

Previous Federal Actions

    Please refer to the proposed delisting rule for the black-capped 
vireo (81 FR 90762, December 15, 2016) for a detailed description of 
previous Federal actions concerning this species.

Background

    Please refer to the proposed delisting rule for the black-capped 
vireo (81 FR 90762, December 15, 2016) for a summary of species 
information.
    Our December 15, 2016, proposed rule was based largely on the SSA 
report, which characterized the species' overall viability in the 
future. Please see ADDRESSES, above, for information on how to obtain a 
copy of the SSA report.

Summary of Biological Status and Threats

Species Description and Needs

    The black-capped vireo is a migratory songbird that breeds and 
nests in south-central Oklahoma, Texas, and the northern states of 
Mexico (Coahuila, Nuevo Le[oacute]n, Tamaulipas), and winters along 
Mexico's western coastal states. In general, black-capped vireo 
breeding habitat is shrublands and open woodlands.
    The resource needs of the black-capped vireo are described in the 
SSA report for individuals, populations, and for the species rangewide. 
Life-history needs are generally categorized as breeding, feeding, and 
sheltering; for migratory species, this may also include habitat for 
migration and wintering. Individual black-capped vireos need a suitable 
breeding habitat patch of at least 1.5 hectares (ha) (3.7 acres (ac)) 
of shrublands with between 35 and 55 percent shrub cover that consists 
largely of deciduous shrubs, often oaks in mesic areas, and with a low 
proportion of junipers. Within breeding habitat patches, shrub mottes 
(groups of shrubs) with deciduous foliage from ground level to 3 meters 
(m) (0 to 9.8 feet (ft)) in height are needed for nest concealment and 
foraging.
    Populations of black-capped vireos are described based on the 
number of adult males the breeding habitat can support. Those sites 
(defined as geographical areas with suitable breeding habitat) capable 
of supporting at least 30 adult males are considered ``manageable 
populations.'' Those sites with suitable breeding habitat capable of 
supporting 100 or more adult males are considered ``likely resilient 
populations,'' that have the ability to withstand disturbances of 
varying magnitude and duration. Brown-headed cowbird (Molothrus ater) 
brood parasitism rates below 40 percent (Tazik

[[Page 16229]]

and Cornelius 1993, p. 46; Wilsey et al. 2014, p. 568) are necessary to 
sustain and expand vireo populations.
    Information on use of habitat during migration is sparse. In 
general, black-capped vireos require airspace for movement and woody 
vegetation for stopovers extending from the northernmost portion of the 
breeding grounds to the extent of the known wintering grounds.
    The winter range of the black-capped vireo occurs entirely on the 
slopes of Mexico's Pacific coast. Arid and semi-arid scrub and 
secondary growth habitat, generally 0.6 to 3.0 m (2 to 10 ft) in 
height, is needed for feeding and sheltering.
    Across its range, the black-capped vireo needs suitable breeding 
habitat to support manageable and likely resilient populations that are 
geographically distributed to allow gene flow and dispersal, low brown-
headed cowbird brood parasitism rates to allow sufficient productivity, 
sufficient airspace and stopover sites for migration, and wintering 
areas of arid and semi-arid scrub and secondary growth habitat along 
the Pacific slopes of western Mexico. During the breeding season, 
habitat requirements appear to be more specialized than during 
wintering and migration. Given the potential for black-capped vireos to 
use a wide range of habitat types during migration and wintering, much 
of the subsequent analysis is focused on breeding habitat.

Species' Current Conditions

    There are no available rangewide population estimates of breeding 
black-capped vireos. However, reported occurrences (sightings) of 
black-capped vireos are available for comparing abundance and 
distribution across timeframes (but see section 4.1, ``Assumptions,'' 
in the SSA report (Service 2016) regarding inherent differences in 
survey effort and the differences between reported occurrences and 
population estimates). At the time of listing in 1987, there were 
approximately 350 reported black-capped vireo occurrences. From 2009 to 
2014, there were 5,244 adult males reported, a 17.5 percent increase 
from the prior review period in 2000 to 2005.
    At the time of listing in 1987, the known population occurred in 4 
Oklahoma counties, 21 Texas counties and 1 Mexican state. The 
consistency of survey effort has varied throughout the years; however, 
it represents the best information available to evaluate abundance and 
distribution rangewide. The known breeding distribution now occurs in 5 
Oklahoma counties, 40 Texas counties, and 3 states in Mexico.
    Information from 2009 to 2014 indicates there are 14 known 
populations with 100 males or more (defined as a likely resilient 
population) throughout the breeding range, 9 of which occur on managed 
lands (under Federal, State, or municipal ownership, or under 
conservation easement) in the United States. An additional 20 
manageable populations (30 or more adult males, but fewer than 100), 10 
of which occur on managed lands, are distributed throughout the range 
in the United States.
    Information gathered from annual black-capped vireo monitoring at 
four publicly managed areas containing the largest known black-capped 
vireo populations represents some of the best data available on the 
species' population trends. These four regularly surveyed areas (Fort 
Hood Military Installation, Fort Sill Military Installation, Kerr 
Wildlife Management Area, and Wichita Mountains Wildlife Refuge) show 
stable or increasing population estimates since 2005. From 2000 to 2005 
these populations represented 64 percent of the known population. From 
2009 to 2014, these four major populations accounted for 40 percent of 
the known rangewide breeding population. The difference in percentage 
suggests the black-capped vireo's distribution is wider than was 
understood in 2000 to 2005. These same data also indicate that 
additional unknown populations likely exist on private lands throughout 
the breeding range. The largest increase in known abundance is an 
additional large population documented in Val Verde County, Texas. The 
four regularly surveyed areas and the Val Verde site were estimated to 
consist of 14,418 adult males in 2013-2014.
    The levels of gene flow between extant populations indicate 
adequate genetic diversity (Vazquez-Miranda et al. 2015, p. 9; Zink et 
al. 2010, entire). This is true despite some variation in studies with 
respect to genetic diversity, gene flow, and population structuring 
(e.g., Barr et al. 2008; Zink et al. 2010; Athrey et al. 2012).
    Little is known about the habits of black-capped vireos during 
migration. Most evidence suggests that there is a southerly, central 
Mexican migratory route following the Sierra Madre Oriental (Marshall 
et al. 1985, p. 4; Farquhar and Gonzalez 2005, entire).
    Vireos banded on the breeding grounds in the United States that 
return in following years suggest adequate availability of resources 
during wintering and migration. Survival rates (estimated from return 
rates) for black-capped vireos at Fort Hood are comparable to the rates 
of other passerines (Ricklefs 1973; Martin 1995; Kostecke and Cimprich 
2008, p. 254).
    Information on migration and wintering of black-capped vireos in 
Mexico is limited to a few studies that document the extent of the 
wintering range and estimate habitat areas. Winter habitat utilized is 
more general and diverse than that of the breeding grounds. While 
specific requirements of winter habitat are unknown, tropical dry 
forests (areas where arid and semi-arid winter habitats occur) exist in 
areas normally inaccessible to development. Habitat modelling has 
suggested wintering areas in Mexico occur across 103,000 to 141,000 
square kilometers (km\2\) (39,769 to 54,440 square miles (mi\2\)) and 
extend farther than previous records have identified, including the 
states of Guerrero and Chiapas (Vega Rivera et al. 2010, p. 101; Powell 
2013, pp. 34-38). Of this area, approximately 7.1 percent (1,000,000 ha 
(2,471,053 ac)) occurs on protected natural areas (national parks, 
reserves, etc.) (Vega Rivera et al. 2010, pp. 98-102). Additionally, 
there are approximately 1,492,400 ha (3,687,801 ac) of lands designated 
as ``important bird areas'' within the estimated winter range (Vega 
Rivera et al. 2011, p. 103). This designation as ``important bird 
areas'' provides some protection to the species. The level of 
protection varies by area (Vega Rivera et al. 2011, p. 103).
    The U.S. portion of the black-capped vireo's range is comprised of 
a diversity of landownerships, from private lands to several forms of 
public ownership. Various conservation actions and programs have been 
developed and implemented in an effort to conserve the species. These 
conservation actions implemented on publicly managed and private lands 
throughout the species' current range have reversed black-capped vireo 
declines within several populations. Ongoing active management on 
publicly managed lands and those under conservation easements has 
resulted in 40 populations in Oklahoma and Texas, varying in size from 
a single adult male to an estimated 7,478 adult males. Of these, 9 are 
considered likely resilient populations and another 10 are considered 
manageable populations. Although information on breeding vireos in 
Mexico is limited, the vireo is currently afforded protected status 
(SEMARNAT 2015, p. 79), known threats appear to be of less magnitude 
than those in the United States, and densities of known populations 
have been documented up to six times as high as populations in

[[Page 16230]]

the United States (Farquhar and Gonzalez 2005, p. 25; Wilkins et al. 
2006, p. 28).
    The contribution of prescribed fire and wildfire to the development 
of suitable breeding habitats in Oklahoma and the eastern portion of 
the species' Texas range is well documented (USFWS 1991, p. 22; 
Campbell 1995, p. 29; Grzybowski 1995, p. 5). In the western portion of 
the species' breeding range in Texas and in Mexico, fire is not as 
essential in maintaining habitat suitability. The use of prescribed 
fire as a habitat management tool is increasing or remains constant 
across most of the United States (Melvin 2015, p. 10). More than 3,156 
ha (7,800 ac) in Oklahoma and more than 48,562 ha (120,000 ac) in Texas 
have been burned annually (2004-2014) with prescribed fire. In 
addition, large amounts of additional acreage is burned each year by 
unplanned wildfire: Oklahoma's annual average is approximately 63,940 
ha (158,000 ac) and Texas' annual average is approximately 322,939 ha 
(798,000 ac)) (NIFC 2014). Although the majority of these burns were on 
Federal lands outside of the black-capped vireo's range, there has been 
an overall increase in the use of prescribed fire as a cost effective 
tool for range and wildlife management.
    Reduction of brood parasitism by brown-headed cowbirds through 
management programs increases black-capped vireo breeding success 
(Eckrich et al. 1999, pp. 153-154; Kostecke et al. 2005, p. 57; Wilkins 
et al. 2006, p. 84; Campomizzi et al. 2013, pp. 714-715). Brown-headed 
cowbird brood parasitism rates below 40 percent are vital to sustaining 
and expanding black-capped vireo populations. The continuation of 
brown-headed cowbird trapping on Federal and private properties and 
expansion of this practice to other properties would help reduce brood 
parasitism rates and improve black-capped vireo breeding success. In an 
effort to manage the brown-headed cowbird populations in Texas, the 
Texas Parks and Wildlife Department has implemented a cowbird trapping 
program, which provides participating landowners a training and 
certification process.
    When the proposed rule was completed, there were eight Service-
approved Habitat Conservation Plans addressing the ``incidental take'' 
of black-capped vireos for project-related impacts since the species 
was listed, all of which are in Texas. In total, approximately 7,843.2 
ha (19,381 ac) of black-capped vireo habitat may be impacted, either 
directly or indirectly, resulting from activities authorized through 
HCPs. To mitigate black-capped vireo habitat loss, the permittees must 
preserve and provide funding for approximately 8,239.4 ha (20,360 ac) 
of habitat restoration and management for off-site black-capped vireo 
habitats as conservation actions under these HCPs. Since the publishing 
of the December 15, 2016, proposed rule (81 FR 90762), an additional 
HCP was completed in June of 2017 for a wind energy project in 
McCulloch County, Texas. This project documented a previously unknown 
locality of more than 150 male black-capped vireos, and provides a 
permanently protected preserve for vireos on over 500 acres.

Recovery Planning and 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 identify site-
specific management actions that will achieve recovery of the species 
and objective, measurable criteria that set a trigger for review of the 
species' status. Methods for monitoring recovery progress may also be 
included in recovery plans.
    Recovery plans are not regulatory documents; instead they are 
intended to establish goals for long-term conservation of listed 
species and define criteria that are designed to indicate when the 
threats facing a species have been removed or reduced to such an extent 
that the species may no longer need the protections of the Act. There 
are many paths to accomplishing recovery of a species, and recovery may 
be achieved without all criteria being fully met. Recovery of a species 
is a dynamic process requiring adaptive management that may, or may 
not, fully follow the guidance provided in a recovery plan.
    The black-capped vireo recovery plan was approved by the Service on 
September 30, 1991 (USFWS 1991). Specific details of recovery for 
delisting the species was indeterminable 27 years ago; therefore, an 
interim objective of reclassification from endangered to threatened 
status was used to develop recovery criteria (USFWS 1991, p. 36). The 
recovery plan includes the following reclassification criteria:
    (1) All existing populations are protected and maintained.
    (2) At least one viable breeding population exists in each of the 
following six locations: Oklahoma, Mexico, and four of six Texas 
regions.
    (3) Sufficient and sustainable area and habitat on the winter range 
exist to support the breeding populations outlined in (1) and (2).
    (4) All of the above have been maintained for at least 5 
consecutive years and available data indicate that they will continue 
to be maintained.
    When the recovery plan was approved in 1991, a viable population 
was estimated, using population viability analysis, to be at least 500 
pairs of breeding black-capped vireos. The recovery plan was intended 
to protect and enhance the populations known at that time, while 
evaluating the possibility of recovery and developing the necessary 
delisting criteria if recovery is found to be feasible. The rangewide 
population was unknown, but the Oklahoma population was thought to be 
fewer than 300 individual birds.
    Comparing the current status of the species to the reclassification 
criteria provides some information about the health of the populations. 
Regarding the first criterion, we would not expect that all known 
populations described in the recovery plan would exist in the same 
locations today because suitable habitat becomes unsuitable over time 
while other unsuitable areas become suitable (e.g. following shrub 
encroachment or fire). Regardless, many of the populations identified 
in the recovery plan continue to thrive, and approximately 67% of known 
populations of greater than 30 birds are under some form of protection. 
From 2009 to 2014, the total black-capped vireo counts and estimates in 
each of the recovery areas, with the exception of Mexico where we have 
limited information, exceeds 500 males, with four recovery areas 
numbering in the thousands (Service 2016, p. 85). Multiple populations 
are present in each of the recovery areas and at least one breeding 
population with more than 500 males is known from three of the four 
Texas recovery areas and from Oklahoma (Service 2016, p. 77-79), 
indicating that criterion (2) has largely been met. Regarding Criterion 
(3), we can evaluate the numbers of birds banded on the breeding 
grounds that return in following years as an indicator of the 
availability of resources on the wintering grounds. In general, black-
capped vireo return rates suggest sufficient resources are available 
during migration and wintering (Service 2016, pp. 88-89). Finally, 
regarding criterion (4), it appears that those criteria were met at the 
time of the 2007 5-yr review and continue to be met today.
    During the 2007 5-year review of the status of the species, it was 
determined

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that the 1991 recovery plan was outdated and did not reflect the best 
available information on the biology of the species and its needs 
(USFWS 2007, p. 5). Therefore, rather than use the existing outdated 
recovery criteria, the Service assessed the species' viability, as 
summarized in the SSA report (Service 2016; see ADDRESSES, above, for 
information on how to obtain a copy of the SSA report) to inform the 
process of making the determination that the black-capped vireo has 
recovered.

Summary of Factors Affecting the Species

    Section 4 of the Act and its implementing regulations (50 CFR part 
424) set forth the procedures for listing species, reclassifying 
species, or removing species from listed status. A species may be 
determined to be an endangered or threatened species due to one or more 
of the five factors described in section 4(a)(1) of the Act: (A) The 
present or threatened destruction, modification, or curtailment of its 
habitat or range; (B) overutilization for commercial, recreational, 
scientific, or educational purposes; (C) disease or predation; (D) the 
inadequacy of existing regulatory mechanisms; or (E) other natural or 
manmade factors affecting its continued existence. A species may be 
reclassified or delisted on the same basis. Consideration of these 
factors was incorporated in the SSA report (Service 2016; see 
ADDRESSES, above, for information on how to obtain a copy of the SSA 
report) as ``causes and effects,'' and projected in future scenarios to 
evaluate viability of the black-capped vireo. The effects of 
conservation measures currently in place were also assessed as part of 
the current condition of the species in the SSA report, and those 
effects were projected in future scenarios.

Causes and Effects

    When the black-capped vireo was listed in 1987, the known threats 
influencing its status were the loss of suitable breeding habitat 
(Factor A) and brood parasitism by brown-headed cowbirds (Factor E). 
These continue to be the primary factors affecting the species' 
viability. The loss of breeding habitat in the United States has been 
linked to changes in vegetation due to fire suppression (vegetational 
succession), grazing and browsing from livestock and native and 
nonnative ungulates, and the conversion of breeding habitat to other 
land uses. In addition, we considered the effects of climate change on 
available breeding and wintering habitat and other potential habitat 
impacts in the winter range in order to assess the status of the 
species throughout its range.

Habitat Loss (Factor A)

    Black-capped vireo breeding habitat is most likely to occur on 
lands categorized in the U.S. Department of Agriculture (USDA) 
Agricultural Census data by landowners as ``rangeland.'' Therefore, 
trends in lands categorized as rangeland is a useful indirect measure 
for estimating the effects of land use changes on the black-capped 
vireo. There has been a general increasing trend since 1987 for 
occurrence of rangeland within the black-capped vireo's U.S. breeding 
range, based on available Agricultural Census data. That is, there has 
been an increase in the amount of lands reported as rangeland. Since 
2002, Oklahoma has reported a 36 percent increase and Texas has 
reported a 4.4 percent increase in rangeland (USDA 2002a, 2002b, 2012a, 
and 2012b).
    The prevalence of goats in Texas in counties where the black capped 
vireo was known to occur was specifically considered a threat to the 
black-capped vireo in 1987. Goat browsing can eliminate shrub foliage 
necessary for black-capped vireo nest concealment. Since that time, 
goats within the U.S. range of the vireo have dramatically decreased, 
largely attributed to the repeal of the National Wool Act of 1954 (7 
U.S.C. 1781 et seq.; repealed by Pub. L. 103-130 (dated November 1, 
1993), with an effective date of December 31, 1995, under section 3(a) 
of Pub. L. 103-130). From 1987 to 2012, reported numbers of goats 
decreased by 46.8 percent in counties where black-capped vireos are 
known to occur (USDC 1987a, 1987b; USDA 2012a, 2012b).
    Cattle, white-tailed deer, and nonnative ungulates are also known 
to impact black-capped vireo habitat by browsing and eliminating shrub 
foliage necessary for nest concealment; however, this impact is to a 
lesser extent than the impacts of goats (Graber 1961, p. 316; Shaw et 
al. 1989, p. 29; Guilfoyle 2002, p. 8; Wilkins et al. 2006, pp. 52-54). 
Cattle numbers have also decreased across the black-capped vireo's 
range from 1987 to 2012 by 37.2 percent (USDC 1987a, 1987b; USDA 2012a, 
2012b). While livestock numbers have decreased, rangeland acres have 
increased. Wilcox et al. (2012) attribute this apparent discrepancy to 
reductions in stocking density. This overall decline in livestock 
density has been driven by changing land ownership and the increase in 
wildlife conservation (Wilcox et al. 2012). White-tailed deer densities 
in the species' range in Texas have increased by 18.3 percent from 2005 
to 2014 (TPWD 2015, p. 27), leading to increased deer browsing, but 
this increase is considerably less than the decreases in goats and 
cattle. In Mexico, a primary economic activity is livestock ranching 
within the breeding range (Morrison et al. 2014, p. 37), although trend 
data are not available. In some areas of Mexico, livestock appears to 
be at low densities (Morrison et al. 2014, p. 37) and may be separated 
from breeding vireos by elevation and, therefore, may not be in direct 
contact with habitat (Farquhar and Gonzalez 2005, p. 30).
    Vegetational succession, or the change in plant species composition 
over time, continues to affect the black-capped vireo habitat in the 
eastern portion of the range in Texas and in Oklahoma. Habitat that is 
considered to be early successional in the eastern portion of the range 
is created naturally or artificially by disturbance, usually by fire. 
In the absence of wildfire or prescribed fire, early successional 
habitats in the eastern portion of the range grow into wooded habitat 
that provides unsuitable structure for vireo nesting. In the western 
portion of the range in Texas and Mexico, suitable black-capped vireo 
habitat does not typically grow into wooded habitat, and succession 
management is less important (Hayden et al. 2001, p. 32; Farquhar and 
Gonzalez 2005, p. 32; McFarland et al. 2012, p. 5).
    Overall, the reduction in numbers of goats and cattle compensates 
for unanticipated increases in deer browsing and contributes to a net 
increase in available breeding habitat. Likewise, the increasing amount 
of reported rangeland acres since listing have likely improved habitat 
conditions within the breeding range. In the eastern portion of the 
range, breeding habitat is considered early successional habitat and 
associated with disturbance such as fire. Because land managers in the 
eastern portion of the range are increasingly using fire as a 
management tool, available breeding habitat has likely increased in 
this portion of the range. In the western portion of the range, such 
disturbance is not necessary to maintain suitable habitat, and much of 
the available breeding habitat is more stable in the long term.

Winter Range (Factor A)

    Black-capped vireos are more general in habitat selection for 
wintering, and can use scrub, disturbed habitats, secondary growth 
habitats, and tropical dry forests as well as shrubs. Although threats 
to the species on its wintering grounds were not identified at the time 
of listing (1987) or during the 2007 5-

[[Page 16232]]

year review, they were considered as part of the species status 
assessment process to determine whether winter habitat availability 
could be a limiting factor. Dry forests in Mexico are a conservation 
concern (Miles et al. 2006, p. 502) and have historically been modified 
for agricultural and other purposes (Powell 2013, p. 100). The majority 
of impacts (greater than 55 percent) to tropical dry forests occurred 
prior to the listing of the black-capped vireo (Powell 2013, pp. 101-
102). Habitat loss still occurs (Powell 2013, pp. 101-102), but the 
extent of habitat specifically important to wintering vireos is 
unknown, but likely diverse, considering the variety of habitats used. 
Habitat models have suggested the winter range may be as large as 
141,000 km\2\ (54,440 mi\2\) in size (Vega Rivera et al. 2010, p. 101). 
Much of this habitat occurs on canyons and slopes and may be 
inaccessible to most anthropogenic impacts.

Brood Parasitism (Factor E)

    Brown-headed cowbirds are brood parasites; females remove an egg 
from a host species nest, lay their own egg to be raised by the adult 
hosts, and the result usually causes the death of the remaining host 
nestlings (Rothstein 2004, p. 375). Brood parasitism by brown-headed 
cowbirds has been documented to affect more than 90 percent of black-
capped vireo nests in some Texas study areas (Grzybowski 1991, p. 4). 
Control of cowbirds through trapping has been shown to significantly 
reduce brood parasitism and increase population productivity of vireos 
(Eckrich et al. 1999, pp. 153-154; Kostecke et al. 2005, p. 28). An 
evaluation of Breeding Bird Survey data shows brown-headed cowbird 
detections have been decreasing in Texas and Oklahoma since 1967, 
specifically in ecoregions where black-capped vireos are known to occur 
(Sauer et al. 2014, entire).
    Furthermore, available data suggest geographic differences in the 
impact cowbirds have on breeding vireos. Cowbird abundance and brood 
parasitism appears to be less prevalent on the western portion of the 
black-capped vireo's range and in Mexico (Bryan and Stuart 1990, p. 5; 
Farquhar and Maresh 1996, p. 2; Farquhar and Gonzalez 2005, p. 30; 
Smith et al. 2012, p. 281; Morrison et al. 2014, p. 18).
    Although cowbird abundance appears to be declining and the effects 
of brood parasitism are reduced in portions of the vireo's range, 
cowbird control continues to be necessary to maintain the current 
number of black-capped vireo populations and individuals in the eastern 
portion of the range in Texas and in Oklahoma. Since the completion of 
the SSA report, a study was published on the effects of brood 
parasitism and local populations, which provided additional information 
indicating some sites with low brood parasitism rates have insufficient 
reproduction to balance mortality and rely on immigration of 
individuals from other areas to avoid extirpation (Walker et al. 2016). 
There are many other factors apart from cowbird brood parasitism that 
may influence resiliency of localities; however, cowbird management 
still remains the most effective means of improving reproductive 
success at numerous localities. We have updated the SSA report to 
reflect this study, and we address the study's implications below, 
under Summary of Comments and Recommendations.

Climate Change (Factor E)

    The effects of climate change are a concern in ecosystems that are 
sensitive to warming temperatures and decreased precipitation, such as 
arid and semi-arid habitats where the black-capped vireo resides. In 
Texas, climate change models generally predict a 3 to 4 degree 
Fahrenheit (1.6 to 2.2 degree Celsius) increase in temperature between 
2010 and 2050 (Nielsen-Gammon 2011, p. 2.23; Banner et al. 2010, p. 8, 
Alder and Hostetler 2013, entire). Predictions on precipitation trends 
over Texas are not as clear (Nielsen-Gammon 2011, p. 2.28), but the 
models indicate that Texas weather will likely become drier (Banner et 
al. 2010, p. 8, Alder and Hostetler 2013, entire; Runkle et al. 2017, 
entire).
    Although the impact from the effects of climate change on shrubland 
habitat required by the black-capped vireo for breeding is uncertain, 
shrub encroachment into grasslands in North America, primarily due to 
fire suppression and livestock grazing, is well documented (Van Auken 
2000, entire; Briggs et al. 2005, entire; Knapp et al. 2007, p. 616). 
Projected warming temperatures and dry conditions will likely influence 
future shrubland dominance (Van Auken 2000, p. 206). Evidence suggests 
that within the far west portion of the black-capped vireo's range, the 
effects of climate change and fire suppression would result in a 
shrubland-dominated landscape (White et al. 2011, p. 541). In this 
scenario, the availability of shrub habitat would be the least 
affected, and potentially more prevalent on the landscape, which may 
increase the available amount of suitable breeding habitat. Following 
the publication of the December 15, 2016, proposed rule (81 FR 90762), 
an additional study was published on the effects of extreme drought on 
a black-capped vireo location in Texas (Col[oacute]n et al. 2017). This 
study provides evidence that extreme conditions of drought may reduce 
reproductive success, increase cowbird brood parasitism, and influence 
choice of vegetation substrate. The effects appear to be regional, 
since another well-studied Texas population did not suffer these 
effects; impacts to the affected population appear to be limited to the 
specific drought year, that is, the affected population appears to have 
recovered the following year. We have updated the SSA report to reflect 
this information, and we address its relevance to this rule below, 
under Summary of Comments and Recommendations.

Species Future Conditions and Viability

    We evaluated overall viability of the black-capped vireo in the SSA 
report (Service 2016; revised 2017 based on information provided during 
the comment period and included in the docket for the final rule; see 
ADDRESSES, above, for information on how to obtain a copy of the SSA 
report) in the context of resiliency, redundancy, and representation. 
Species viability, or the ability to sustain populations long term, is 
related to the species' ability to withstand catastrophic events 
(redundancy), the ability to adapt to changing environmental conditions 
(representation), and the ability of populations to withstand 
disturbances of varying magnitude and duration (resiliency). The 
viability of a species is also dependent on the likelihood of new 
stressors (processes or events with a negative impact on the species) 
or continued threats (a stressor and its source) now and in the future 
that act to reduce a species' redundancy, representation, and 
resiliency and the species overall ability to withstand such stressors.
    In the SSA report, we forecast the viability of known populations 
of black-capped vireos over the next 50 years. We chose 50 years to 
reflect specific climate change models that are relevant to the black-
capped vireo and its habitat. The 50 year timeframe also reflects our 
ability to project land management decisions. We developed multiple 
future conditions scenarios for the known manageable and likely 
resilient populations based on both continued management (i.e., 
continuing the current conditions of habitat and cowbird management) 
and decreased management. For the decreased management scenarios, 
populations on private lands were considered to have

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no management in the future, while habitat and cowbird management on 
publicly managed lands was projected to diminish in scale or frequency 
that would not continue to provide for the needs of the species. The 
decreased management scenario projected the future conditions of the 
species without the continued protections of the Act. All of the 
scenarios are considered to be within the realm of reasonable 
possibility. Even in the worst case scenario, at least 26 of the 34 
known manageable and likely resilient populations have a moderate to 
high (i.e., greater than 50 percent) likelihood of persisting over the 
next 50 years, indicating adequate resiliency of those populations and 
redundancy across the species' range. Likewise, those populations 
projected in the worst case scenario are distributed throughout the 
range as multiple populations within each of the different areas of 
representation, indicating adequate redundancy within each of the 
representative areas (as described below).
    We evaluated several studies with respect to representation in the 
black-capped vireo, mostly involving genetic diversity. Although there 
is discrepancy between studies, there is evidence that adequate gene 
flow for healthy genetic diversity exists across known breeding 
populations. Additionally, there is a diversity of habitat types 
utilized within both the breeding and wintering ranges. For these 
reasons, the black-capped vireo appears to have adequate representation 
both genetically and ecologically to allow for adaptability to 
environmental changes.
    Resiliency, in terms of habitat capable of supporting greater than 
100 adult males, for the eastern portion of the black-capped vireo's 
breeding range is dependent on vegetation and cowbird management. In 
the western portion of the range, population resiliency is higher, 
because management is not required to maintain suitable breeding 
habitat and threats related to cowbirds are less severe. Since 2005, 
resiliency, in terms of population size, has increased in regularly 
monitored populations, and under future scenarios, the number of likely 
resilient populations either increases or remains close to current 
levels (Service 2016); therefore, we expect that trend in increasing 
resiliency to continue into the future.
    The recovery of the black-capped vireo is due, in part, to 
conservation actions, in the form of habitat and cowbird management in 
parts of the species' breeding range. Many localities of vireo habitat, 
especially in the eastern portion of the breeding range, will require 
continued management activities to persist. In considering its 
management needs, the forecast of future conditions includes scenarios 
based on the needs of the species, stressors, identification of 
additional populations, and restoration efforts. Our forecasts that 
produce stable or increasing resiliency and redundancy reflect the 
differences in the current and projected future conditions of the 
species compared to the status assessment that was conducted to support 
the 1987 listing decision.
    The future persistence of the species in some places will require 
active management of threats. Prescribed fire as a management tool is a 
cost effective way to restore prairies and shrublands and to reduce 
impacts of invasive juniper, and is often used to benefit game species 
(e.g., deer, wild turkey). Such management actions may directly and 
indirectly benefit black-capped vireos when they occur within the 
breeding range. The Service has obtained commitments from our key 
Federal, State, and private conservation partners (included in the 
docket with this final rule), who are largely responsible for the 
recovery of the species, to continue to manage black-capped vireo 
populations on publicly managed lands and to promote management actions 
across the breeding range of the species. For example, the Integrated 
Natural Resource Management Plans for Fort Hood and Fort Sill will 
continue management actions that directly benefit black-capped vireos. 
Likewise, prescribed fire is being used as a management tool for a 
variety of species at most publicly managed areas within the current 
breeding range of the black-capped vireo, and those management actions 
will continue regardless of the listing status of black-capped vireos. 
Black-capped vireo populations existing on properties under management 
through public ownership (Federal, State, municipal) or easement are 
generally projected to persist under short- and long-term conditions. 
Even under diminished management specific to black-capped vireos, many 
of these locations are expected to be better suited than unmanaged 
lands to provide resources for the black-capped vireo, often due to the 
conservation mission of the property (e.g., state parks).

Summary of Updates to SSA Report and Post-Delisting Monitoring Plan

    As discussed in this rule, two recent studies have been published 
relevant to the status of the black-capped vireo. We have updated the 
SSA report (included in the docket with this final rule) to reflect 
this information. Additionally, we corrected errors in Table 14 of the 
SSA report. This table summed the forecasted scenarios of Table 13, 
which was correct.
    Based on comments received, we have clarified the role of 
management for the species as it pertains to ``conservation reliance'' 
and worked with our Federal, State and private partners to develop the 
post-delisting monitoring (PDM) plan and commitments to managing the 
species on lands under their authority. Specifically, in the SSA 
report, as well as the December 15, 2016, proposed rule (81 FR 90762), 
the impact of brown-headed cowbird brood parasitism on certain 
locations was expressed in terms of sustainability and expansion of 
populations. Additionally, the species was identified as 
``conservation-reliant'' due to successful recovery actions, largely 
cowbird management, being implemented. The Service concludes that 
cowbird management was a major factor leading to the recovery of the 
species. Thus, the importance of cowbird management was discussed in 
the SSA report and proposed rule. Particularly, the black-capped vireo 
population in Oklahoma and localities in the eastern portion of the 
Texas range may be reliant on cowbird management periodically, or 
perpetually, to ensure minimal losses of current population numbers. In 
this regard, we believe the species may be ``conservation reliant,'' 
due to efforts necessary to retain healthy shrublands and reduce brown-
headed cowbird brood parasitism under certain conditions in portions of 
the range. However, the proposal to remove the species from the Federal 
List of Endangered and Threatened Wildlife was not made on the 
condition of continued management. The future scenarios forecast in the 
SSA report included a ``worst case'' scenario in which all management 
for the species would cease. In the worst case scenario, we acknowledge 
that the species' resiliency, redundancy, and representation over the 
next 50 years would likely decline, but would not meet the definition 
of endangered or threatened. We therefore proposed to delist the 
species.
    Based on the comprehensive information collected for the SSA 
report, there is inherent uncertainty in forecasting future threats and 
population status scenarios over a 50-year timeframe. To address this 
uncertainty and ensure that the black-capped vireo continues to 
prosper, the SSA report and proposed rule noted the importance of 
continued management of known populations of the species. To

[[Page 16234]]

further this recommendation, the Service has obtained mutual 
commitments with many of our partners in the form of cooperative 
management agreements or other strategies to continue to manage known 
populations of the black-capped vireo and implement the PDM plan (see 
draft PDM plan: 83 FR 11162; March 14, 2018). These cooperative 
management agreements are included the docket with this final rule and 
in the PDM plan, and provide assurances that post-delisting monitoring 
will detect trends in the black-capped vireo's status and threats. 
Please see ADDRESSES, above, for information on how to obtain a copy of 
the PDM plan.

Summary of Comments and Recommendations

    In the proposed rule published on December 15, 2016 (81 FR 90762), 
we requested that all interested parties submit written comments on the 
proposal by February 13, 2017. We also contacted appropriate Federal 
and State agencies, scientific experts and organizations, and other 
interested parties and invited them to comment on the proposal. 
Newspaper notices inviting general public comment were published in the 
San Angelo Standard-Times, Alpine Avalanche, Lawton Oklahoma 
Constitution, and the Austin American Statesman. We did not receive any 
requests for a public hearing. All substantive information provided 
during comment periods has either been incorporated directly into this 
final determination or is addressed below.

State and Peer Reviewer 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 failure to adopt regulations consistent with the 
agency's comments or petition. We solicited and received comments from 
both the Oklahoma Department of Wildlife Conservation (ODWC) and the 
Texas Parks and Wildlife Department (TPWD). Both agencies supported the 
delisting of the black-capped vireo, acknowledged the significant 
progress on private lands that have improved range conditions, and 
offered to continue to assist in post-delisting monitoring and other 
partnership opportunities.
    TPWD expressed concern about the lack of information from Mexico, 
and suggested that the species continues to be threatened in that 
country by development and some forms of incompatible agriculture. 
However, TPWD stated that the extent of impact to the vireo is 
essentially unknown. Even with the limited information available, the 
SSA analysis indicated continued persistence over the 50-yr projected 
timeframe. Black-capped vireo return rates generally suggest sufficient 
resources are available during migration and wintering, but we agree 
with TPWD that additional study in this portion of the species' range 
is important and support efforts to obtain information related to the 
status of the vireo from Mexico.
    In accordance with our peer review policy published on July 1, 1994 
(59 FR 34270), we solicited expert opinion from three knowledgeable 
individuals regarding the scientific data and interpretations contained 
in the SSA report supporting this final rule. We received responses 
from all three of the peer reviewers.
    We reviewed all comments we received from the peer reviewers for 
substantive issues and new information regarding the black-capped 
vireo. The peer reviewers had no significant objection to the analysis 
provided in the SSA report. In general, the peer-review comments were 
largely minor (editorial) or easily addressed. Substantive comments 
were specifically addressed, and did not involve changes to the 
viability analysis of the SSA report. A summary of the substantive peer 
reviewer comments and responses are available at https://www.regulations.gov under Docket No. FWS-R2-ES-2016-0110.

Public Comments

    We received comments from 32 respondents. We reviewed all comment 
letters provided and addressed the substantive comments. Those 
substantive comments are grouped together in related categories below.
    (1) Comment: Two commenters suggested the use of resiliency, 
redundancy, and representation (the 3Rs) to characterize viability for 
the black-capped vireo is not appropriate. They noted the lack of 
citations and methodology in the SSA report, as well as the 3R model 
being insufficiently tested for use in assessing species' viability.
    Our Response: There are many publications in the scientific 
literature that explore the use of the conservation biology principles 
of resiliency, redundancy, and representation to characterize viability 
(e.g., Shaffer and Stein 2000; Svancara et al. 2005; Carroll et al. 
2010; Redford et al. 2011; Waples et al. 2013; Neel et al. 2014; Wolf 
et al. 2015). We have often used this conservation planning framework 
in our recovery plans, and this is a fundamental concept applied 
explicitly in our species status assessments. We consider our reliance 
on the 3Rs to be use of the best available scientific and commercial 
information. We recognize that appropriate citations were not initially 
included in the SSA report and have now added them to the updated 
report.
    (2) Comment: One commenter stated that the threat of climate change 
should include increasing frequency and severity of drought, wildfires, 
and flooding.
    Our Response: We evaluated the concern of climate change on the 
species by reviewing relevant studies on the species and potential 
habitat factors that could occur in the next 50 years. Flooding does 
not appear to be a stressor for black-capped vireos, with the possible 
exception of the population occurring near Independence Creek in Texas, 
which, unlike most other localities, utilizes the riparian corridor for 
nesting.
    In the SSA report, we discuss the issue of wildfire largely in 
terms of historical suppression leading to the threat of vegetational 
succession in habitats within the eastern portion of the species' 
range. We acknowledge that wildfire is a stressor to the species; 
however, it generally results in temporary impacts and is generally 
believed to have an overall positive effect to the species over time. 
As a result of historical fire suppression, land managers use 
prescribed fire to promote ecosystem health, and in the case of the 
black-capped vireo, as a tool to sustain high-quality breeding habitat.
    We discuss drought effects within the SSA report, specifically 
regarding a future model that suggests an increase in shrubland 
habitats within the breeding range of the species, which may be 
beneficial since the black-capped vireo nests in shrubland habitats.
    The ability to predict and associate drought with climate change is 
complicated. A new study was published in 2017 (Col[oacute]n et al. 
2017) that evaluated the effects of the extreme drought of 2011 on a 
large population of black-capped vireos in Texas. This study provides 
evidence that extreme conditions of drought may reduce reproductive 
success, increase cowbird brood parasitism, and influence choice of 
vegetation substrate. The effects appear to be localized, since another 
well-studied Texas population did not

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suffer these effects; impacts to the affected population appear to have 
been limited to the specific drought year, that is, the affected 
population appears to have recovered the following year.
    A study evaluating the 2011 drought, which is the driest 
consecutive 12-month period in Texas records, surmises that the 
heatwave and drought were not consistent with regional trends (since 
the mid-1900s) and were largely attributed to anomalous sea surface 
temperatures related to La Ni[ntilde]a conditions in the Pacific Ocean, 
rather than anthropogenic effect on climate (Hoerling et al. 2013, 
entire). Global climate models do predict increasing drought severity 
and frequency for most of North America; however, past trends over the 
central United States, including portions of Texas, have shown 
decreasing frequency and intensity of droughts (Pan et al. 2004, 
entire; Hoerling et al. 2013, p. 2812). Regional-scale feedback 
processes that lead to replenishment of seasonally depleted soil 
moisture, thereby increasing late-summer evapotranspiration and 
suppressing daytime maximum temperatures may partly explain the 
observed late 20th century temperature trend in the central U.S. and 
these effects may reduce the magnitude of climate change effects within 
the species' range (Pan et al. 2004, p. L17109). We have updated the 
SSA report to reflect the new study (Col[oacute]n et al. 2017); 
however, the information does not change the analysis.
    (3) Comment: Several commenters discussed the issue of brown-headed 
cowbird brood parasitism. The majority commented that cowbird 
management continues to be necessary and will likely be curtailed 
following the black-capped vireo's delisting. A recently published 
study was also provided (Walker et al. 2016), with new information 
regarding vireo populations and brood parasitism.
    Our Response: The SSA report identifies the threat of brown-headed 
cowbird brood parasitism, as well as the management actions that have 
been successfully implemented to reduce the impacts on populations of 
black-capped vireos. We recognize the efforts of our conservation 
partners in managing the threat, which is partly responsible for the 
recovery of the species. Our analysis in the SSA report includes a 
scenario in which cowbird management did not occur and the effect it 
may have on vireo populations up to 50 years in the future. Based on 
the criteria we established under several assumptions, we predict the 
scenario would result in the reduction of known populations across the 
breeding range. However, the status of the species still would not meet 
the definition of endangered or threatened.
    The assumptions of this analysis, as with any forecast of future 
conditions, are accompanied by uncertainty, which we acknowledge in the 
SSA report. To reduce uncertainty, the Service has obtained commitments 
from key conservation partners to continue to manage localities for the 
benefit of the black-capped vireo under their authorities. These 
commitments, included in the PDM plan, further acknowledge the 
partnerships of State and Federal entities who have worked to recover 
the species.
    A recently published paper (Walker et al. 2016) was submitted with 
comments on the effectiveness of cowbird management and resiliency. In 
addition to reaffirming the importance of cowbird management on 
reproductive success, several study sites with low brood parasitism 
rates were determined to be sites that have insufficient reproduction 
to balance mortality and rely on immigration of individuals from other 
areas to avoid extirpation in the 4-year period of observation. The 
commenter suggests that some populations with cowbird management and 
low brood parasitism rates may still not be sustainable. Additionally, 
it was recommended that resiliency for black-capped vireo populations 
would be better measured by reproductive success and survival. We agree 
that there are many other factors apart from cowbird brood parasitism 
that may influence resiliency of localities; however, cowbird 
management still remains the most effective means of improving 
reproductive success at numerous localities. We encourage additional 
study of other factors that contribute to increased resiliency, 
including those that influence brood parasitism effects on reproductive 
success. We also agree that demographic factors, such as reproductive 
success and survival are good metrics for resiliency; unfortunately, 
those metrics are only available for a small portion of localities 
within the breeding range.
    (4) Comment: Two commenters addressed the issue of white-tailed 
deer browsing in vireo habitat. One provided a different perspective of 
the deer densities given in the SSA report, while the other stated 
there was no evidence to indicate deer browsing is less of a threat 
than goats and cattle.
    Our Response: The SSA report includes deer densities in Texas, 
which are reported on an annual basis by TPWD. While we acknowledge the 
differing methodology provided by the commenter for calculating the 
change in these figures, we believe that weighting the average of deer 
densities would not substantially change the average percent change 
provided in the SSA report, because of the relatively similar sizes of 
the Resource Management Units within ecoregions. The SSA report shows 
the positive trend of estimated deer density numbers in central Texas, 
which is of concern to black-capped vireos. However, deer are game 
animals regulated by the States, which provide monitoring and 
management options similar to other threats to the species that have 
been managed. The potential impact of deer versus livestock on browse 
(and thus potential black-capped vireo habitat) is appropriately 
addressed in the SSA report (Graber 1961, p. 316; Guilfoyle 2002, p. 
8).
    (5) Comment: One commenter noted the lack of records from the 
vireo's northern range in Kansas and Nebraska, suggesting permanent 
habitat loss or other issues in those States.
    Our Response: The prevalence of the black-capped vireo in Kansas 
has been reported in only a few publications, notably a regular 
occurrence in Comanche County. However, the Service noted in its 2007 
black-capped vireo 5-year review that the species has not been 
documented in Kansas since the 1950s, and its range no longer extends 
past central Oklahoma. The Nebraska records are even more limited, and 
the species may have only been an accidental summer visitor in that 
State (Graber 1961, p. 313). For these reasons, the 1991 recovery plan 
only included the States of Oklahoma and Texas, as well as Mexico, as 
part of the recovery strategy. The SSA report for the black-capped 
vireo fully acknowledges the limited northern extent of the breeding 
range; however, the species has had an increasing population and 
distribution over the last 10 to 15 years.
    (6) Comment: One commenter provided an article indicating there 
could be millions of exotic herbivores within the range.
    Our Response: The article cited by the commenter (Texotics, Texas 
Parks & Wildlife Magazine, April 2007) is not peer reviewed and does 
not meet the standard for using the best available scientific 
information. We understand that the prevalence of exotic ungulates 
within the range of the vireo may have an influence on habitat 
availability. However, we are unaware of any evidence of their 
influence or scientific studies that have specifically addressed the 
impacts of exotic ungulates on habitats used by the black-capped vireo. 
During development of the SSA report, we reached out to our State 
partners for information related to trends and

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estimates of exotics across the region, and were informed that the 
States did not track this information and were unaware of reliable 
estimates.
    (7) Comment: Two commenters stated that feral hogs are a threat to 
the species and were not considered in the SSA report.
    Our Response: Feral hogs are a problem for land managers across the 
black-capped vireo's range. They may influence oak recruitment, 
increase erosion, and damage individual trees. However, there is no 
evidence suggesting that feral hog prevalence is a threat to the 
species.
    (8) Comment: One commenter indicated there were no assurances that 
Fort Hood Military Installation will incorporate vireo management 
actions into its integrated natural resources management plan (INRMP).
    Our Response: The Army continues to be an important partner in the 
conservation of the black-capped vireo. In particular, Fort Hood has 
provided a substantial amount of research and management toward the 
black-capped vireo, which has had a profoundly positive effect on the 
population. The Army's commitment to the species has resulted in the 
largest known population under a single management authority at Fort 
Hood. The Army strives to sustain native ecosystems at its 
installations to support military activities, which includes shrubland 
habitat utilized by the black-capped vireo at Forts Hood and Sill. 
Therefore it is reasonable to expect that the numerous years of 
research and management of this species is an investment the Army would 
maintain. However, to further address this issue, we have obtained a 
written commitment from the Army that both Fort Hood and Fort Sill will 
utilize their authorities under the Sikes Act (16 U.S.C. 670 et seq.) 
to ensure the species continues to thrive at those installations after 
it is delisted. This commitment is included in the PDM plan.
    (9) Comment: Three commenters stated that the information regarding 
genetic diversity and structure presented in the SSA report does not 
reflect the intent or findings of the Vasquez-Miranda et al. 2015 
research.
    Our Response: We disagree with the commenters. Our SSA report 
summarizes the available and relevant studies on the genetic 
variability in the black-capped vireo. The Vasquez-Miranda et al. 
(2015) paper was the most recent study on the subject, and is 
summarized to support similar hypotheses that genetic structuring 
within the breeding range is not apparent, or biologically significant. 
We contacted the authors of the study and received affirmation that our 
interpretation of their study is appropriately summarized in the SSA 
report.
    (10) Comment: Three commenters stated that, contrary to the data 
provided in the SSA report, goat densities in Texas are not declining.
    Our Response: The data provided in the SSA report were collected 
from the USDA's Agricultural Census. These statistics show goat 
densities across the vireo's range have declined since 1992. Another 
study (Wilcox et al. 2012) of livestock densities in Texas arrives at a 
similar conclusion. The goat population numbers reported from Texas 
have continually declined since the repeal of the National Wool Act of 
1954.
    (11) Comment: We received two comments that state that the SSA 
report does not adequately address habitat loss caused by development 
in central Texas.
    Our Response: The SSA report indirectly addresses habitat loss 
through an accounting of reported rangeland/pastureland statistics 
across the breeding range of the black-capped vireo. Black-capped vireo 
habitat can occur on small patches on undeveloped land throughout the 
breeding range in the United States. Using the USDA Agricultural Census 
of land use within the species' range, an indirect measure of land use 
changes can be tracked over time. The SSA report indicates that 
reported land use changes within a majority of the species' range do 
not appear to threaten the availability of habitat. When the species 
was evaluated in 1985, a population of black-capped vireos in central 
Texas near Austin, which consisted of approximately 33 pairs, was 
thought to be the largest known to exist. Currently, it is estimated 
that more than 200 pairs occur in the area just west of Austin.
    (12) Comment: One commenter stated that the SSA report provides 
misinformation concerning juniper trees in relation to black-capped 
vireo habitat.
    Our Response: We believe the SSA report accurately describes the 
importance of juniper occurring within black-capped vireo habitat. In 
general, while juniper trees may be used for nesting and foraging, it 
is not a preferred nesting substrate for the species. Juniper is a 
problem in large portions of the species' range due to its invasive 
nature, which often renders breeding habitat unsuitable within just a 
few years. Except in some c