DEPARTMENT OF THE INTERIOR
Fish and Wildlife Service
50 CFR Part 17
[Docket No. FWS-R3-ES-2011-0028; MO 92210-0-0008]
Endangered and Threatened Wildlife and Plants; 90-Day Finding on
a Petition To List the Golden-Winged Warbler as Endangered or
Threatened
AGENCY: Fish and Wildlife Service, Interior.
ACTION: Notice of petition finding and initiation of status review.
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SUMMARY: We, the U.S. Fish and Wildlife Service, announce a 90-day
finding on a petition to list the golden-winged warbler (Vermivora
chrysoptera) as endangered or threatened under the Endangered Species
Act of 1973, as amended (Act). Based on our review, we find that the
petition presents substantial scientific or commercial information
indicating that listing the golden-winged warbler may be warranted.
Therefore, with the publication of this notice, we are initiating a
review of the status of the species to determine if listing the golden-
winged warbler is warranted. To ensure that this status review is
comprehensive, we are requesting scientific and commercial data and
other information regarding this species. Based on the status review,
we will issue a 12-month finding on the petition, which will address
whether the petitioned action is warranted, as provided in the Act.
DATES: To allow us adequate time to conduct this review, we request
that we receive information on or before August 1, 2011. Please note
that if you are using the Federal eRulemaking Portal (see ADDRESSES
section, below), the deadline for submitting an electronic comment is
11:59 p.m. Eastern Time on this date. After August 1, 2011, you must
submit information directly to the Wisconsin Ecological Services Field
Office (see FOR FURTHER INFORMATION CONTACT section below). Please note
that we might not be able to address or incorporate information that we
receive after the above requested date.
ADDRESSES: You may submit information by one of the following methods:
Federal eRulemaking Portal: http://www.regulations.gov. In the box
that reads ``Enter Keyword or ID,'' enter the Docket number for this
finding, which is FWS-R3-ES-2011-0028. Check the box that reads ``Open
for Comment/Submission,'' and then click the Search
[[Page 31921]]
button. You should then see an icon that reads ``Submit a Comment.''
Please ensure that you have found the correct rulemaking before
submitting your comment.
U.S. mail or hand-delivery: Public Comments Processing, Attn: FWS-
R3-ES-2011-0028; Division of Policy and Directives Management; U.S.
Fish and Wildlife Service; 4401 N. Fairfax Drive, MS 2042-PDM;
Arlington, VA 22203.
We will post all information we receive on http://www.regulations.gov. This generally means that we will post any
personal information you provide us (see the Request for Information
section below for more details).
FOR FURTHER INFORMATION CONTACT: Field Supervisor, Wisconsin Ecological
Services Office, U.S. Fish and Wildlife Office, 2661 Scott Tower Drive,
New Franken, WI 54229-9565; by telephone (920-866-1725); or by
facsimile (920-866-1710). If you use a telecommunications device for
the deaf (TDD), please call the Federal Information Relay Service
(FIRS) at 800-877-8339.
SUPPLEMENTARY INFORMATION:
Request for Information
When we make a finding that a petition presents substantial
information indicating that listing a species may be warranted under
section 4(b)(3)(B) of the Act, we are required to promptly review the
status of the species (status review). For the status review to be
complete and based on the best available scientific and commercial
information, we request information on golden-winged warbler (Vermivora
chrysoptera) from governmental agencies, Native American Tribes, the
scientific community, industry, and any other interested parties. We
seek information on:
(1) The species' biology, range, and population trends, including:
(a) Habitat requirements for feeding, breeding, and sheltering;
(b) Genetics and taxonomy, such as information related to the
hybridization between the golden-winged warbler and the blue-winged
warbler (Vermivora cyanoptera);
(c) Historical and current range, including distribution patterns;
(d) Historical and current population levels, and current and
projected trends; and
(e) Past and ongoing conservation measures for the species, its
habitat, or both.
(2) The factors that are the basis for making a listing
determination for a species under section 4(a) of the Endangered
Species Act of 1973, as amended (Act) (16 U.S.C. 1531 et seq.), which
are:
(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.
If, after the status review, we determine that listing the golden-
winged warbler is warranted, we will propose critical habitat (see
definition in section 3(5)(A) of the Act), under section 4 of the Act,
to the maximum extent prudent and determinable at the time we propose
to list the species. Therefore, within the geographical range currently
occupied by the golden-winged warbler, we request data and information
on:
(1) What may constitute ``physical or biological features essential
to the conservation of the species'';
(2) Where such physical and biological features are currently
found; and
(3) Whether any of these features may require special management
considerations or protection.
In addition, we request data and information on ``specific areas
outside the geographical area occupied by the species'' that are
``essential to the conservation of the species.'' Please provide
specific comments and information as to what, if any, critical habitat
you think we should propose for designation if the species is proposed
for listing, and why such habitat meets the requirements of section 4
of the Act.
Please include sufficient information with your submission (such as
scientific journal articles or other publications) to allow us to
verify any scientific or commercial information you include.
Submissions merely stating support for or opposition to the action
under consideration without providing supporting information, although
noted, will not be considered in making a determination. Section
4(b)(1)(A) of the Act directs that determinations as to whether any
species is an endangered or threatened species must be made ``solely on
the basis of the best scientific and commercial data available.''
You may submit your information concerning this status review by
one of the methods listed in the ADDRESSES section. If you submit
information via http://www.regulations.gov, your entire submission--
including any personal identifying information--will be posted on the
Web site. If you submit a hardcopy that includes personal identifying
information, you may request at the top of your document that we
withhold this personal identifying information from public review.
However, we cannot guarantee that we will be able to do so. We will
post all hardcopy submissions on http://www.regulations.gov.
Information and supporting documentation that we received and used
in preparing this finding is available for you to review at http://www.regulations.gov, or you may make an appointment during normal
business hours at the Wisconsin Ecological Field Office (see FOR
FURTHER INFORMATION CONTACT).
Background
Section 4(b)(3)(A) of the Act (16 U.S.C. 1533(b)(3)(A)) requires
that we make a finding on whether a petition to list, delist, or
reclassify a species presents substantial scientific or commercial
information indicating that the petitioned action may be warranted. We
are to base this finding on information provided in the petition,
supporting information submitted with the petition, and information
otherwise available in our files. To the maximum extent practicable, we
are to make this finding within 90 days of our receipt of the petition
and publish our notice of the finding promptly in the Federal Register.
Our standard for substantial scientific or commercial information
within the Code of Federal Regulations (CFR) with regard to a 90-day
petition finding is ``that amount of information that would lead a
reasonable person to believe that the measure proposed in the petition
may be warranted'' (50 CFR 424.14(b)). If we find that substantial
scientific or commercial information was presented, we are required to
promptly conduct a species status review, which we subsequently
summarize in our 12-month finding.
Petition History
On February 10, 2010, we received a petition, from Anna Sewell,
requesting the golden-winged warbler be listed as endangered or
threatened under the Act. The petition clearly identified itself as
such and included the requisite identification information for the
petitioner, as required by 50 CFR 424.14(a). In an April 16, 2010,
letter to the petitioner Anna Sewell, we responded that we had reviewed
the information presented in the petition and determined that issuing
an emergency regulation temporarily listing the species under section
4(b)(7)
[[Page 31922]]
of the Act was not warranted. This finding addresses the petition.
Previous Federal Action(s)
To date, no Federal actions have been taken with regard to the
golden-winged warbler.
Species Information
The golden-winged warbler (Vermivora chrysoptera) is a neotropical
migrant (breeding in North America and wintering in Central and South
America) belonging to the Order Passeriformes and Family Parulidae
(Sibley 2003, p. 429). It is classified as a discrete species by the
American Ornithologists' Union (AOU 1998, p. 534). The golden-winged
warbler is a small-sized passerine, weighing only 8.8 grams (g) (0.31
ounces (oz)). Total body length is 120.65 millimeters (mm) (4.75 inches
(in)), with a wingspan of 190.5 mm (7.5 in). Diagnostic features
include slate gray plumage on the chest, breast, nape and mantle, with
contrasting yellow patches on the upper wing coverts (sets of small
feathers that cover the upper wing area) and crown. An adult male in
breeding plumage expresses a black throat patch and auriculars (groups
of feathers that cover the sides of a bird's head where the bird's ear
openings are located), with contrasting white supercilium (a plumage
feature on the head) and malar region (around the cheeks). All of those
features are less distinct in females. Both sexes can show a yellow
wash on the mantle extending to secondary coverts (Confer 1992, not
paginated; Sibley 2003, p. 429).
Golden-winged warblers breed across the north-central and eastern
United States, expanding into southeastern Canada. The breeding range
can be thought of as two distinct areas: The northern portion, which
extends into southern Canada (southwestern Quebec, Ontario, Manitoba,
and eastern Saskatchewan) and spreads south into Minnesota, Wisconsin,
and Michigan, and the eastern portion, which includes parts of the
Appalachians (Georgia, North Carolina, and Tennessee) and into
Kentucky, Virginia, West Virginia, Pennsylvania, and New York, with low
numbers in Connecticut, Vermont, and New Hampshire (InfoNatura 2007;
Buehler et al. 2010, p. 8, 31). Breeding locations between the two
distinct areas (Indiana, Ohio, and Illinois, and western New York) hold
low numbers of birds (Sauer et al. 2008, not paginated; Buehler et al.
2006, not paginated). The northern and eastern breeding ranges are
linked by a narrow corridor located in the St. Lawrence River Valley in
north central New York (Buehler et al. 2010, p. 8). Wintering locations
include areas in southern Central America and northern South America
(Buehler et al. 2006, not paginated).
For breeding sites, the golden-winged warbler depends mostly on
early successional habitats. These are habitats that have previously
undergone an amount of disturbance by a natural or human-caused event
that creates a structurally diverse landscape. These habitats can occur
in upland or lowland areas (Buehler et al. 2010, p. 2). Landscapes that
consist of forest edge, shrubs, forests with open canopy, habitats with
grassy openings, and wetlands with scattered trees can be viable
nesting habitats (Rossell et al. 2003, p. 1099; Buehler et al. 2010, p.
10). Breeding sites have been documented in abandoned farmlands,
powerline cuts, recently logged sites, and locations along stream
borders (Confer 1992, not paginated; Service 2009, not paginated).
Habitat tracts of 10-50 hectares (ha) (24-37 acres (ac)) can support
several pairs and are preferred over both smaller and larger areas
(Confer 1992, not paginated). Nest success measures vary throughout
breeding range and within the breeding season; however, rough estimates
are between 40 percent at sites in New York to approximately 75 percent
at sites in North Carolina (Buehler et al. 2007, p. 1440; Buehler et
al. 2010, p. 20-21). Population estimates are approximately 210,000
individuals globally (Partners in Flight PIF Landbird Database).
The diet of the golden-winged warbler consists of small bugs,
larvae, and spiders (Service 2009, not paginated). Golden-winged
warblers can lay three to six eggs, in nests that are low to the ground
and concealed by vegetation (Buehler et al. 2007, p. 1440).
Evaluation of Information for This Finding
Section 4 of the Act (16 U.S.C. 1533) and its implementing
regulations at 50 CFR 424 set forth the procedures for adding a species
to, or removing a species from, the Federal Lists of Endangered and
Threatened Wildlife and Plants. 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.
In considering what factors constitute threats, we must look beyond
the exposure of the species to a factor to evaluate whether the species
may respond to the factor in a way that causes actual impacts to the
species. If there is exposure to a factor and the species responds
negatively, the factor may be a threat, and, during the subsequent
status review, we attempt to determine how significant a threat it is.
The threat may be significant if it drives, or contributes to the risk
of, extinction of the species such that the species may warrant listing
as endangered or threatened as those terms are defined in the Act. The
identification of factors that could impact a species negatively may
not be sufficient to compel a finding that substantial information has
been presented suggesting that listing may be warranted. The
information should contain evidence or the reasonable extrapolation
that any factor(s) may be operative threats that act on the species to
the point that the species may meet the definition of endangered or
threatened under the Act.
In making this 90-day finding, we evaluated whether information
regarding threats to the golden-winged warbler, as presented in the
petition and other information available in our files, is substantial,
thereby indicating that the petitioned action may be warranted. Our
evaluation of this information is presented below.
A. The Present or Threatened Destruction, Modification, or Curtailment
of the Species' Habitat or Range.
Information Provided in the Petition
The petition claims that threats causing the present or threatened
destruction, modification, or curtailment of the golden-winged
warbler's habitat or range include habitat loss and modification. The
petition suggests that loss of early successional habitat has
contributed to declining population trends throughout the species'
range (Petition, p. 11; Hunter et al. 2001; NatureServ Explorer).
Golden-winged warblers require early successional landscapes
originating from natural or anthropogenic disturbance. Prior to
European settlement, early successional landscapes occurred via
stochastic events such as natural fires and storms, and through
disturbances to landscapes from other species (for example, bison, elk,
and beaver habitat modifications) (Petition, p. 11; Hamel et al. 2005).
After European settlement in the
[[Page 31923]]
19th century, conversion of natural landscapes to agriculture resulted
in the suppression of natural fires and a decrease in natural land
disturbance. Golden-winged warblers shifted from using naturally
created, early successional breeding habitat, to early successional
habitat created by anthropogenic means (Petition, p. 12; Klaus and
Buehler 2001). Within recent decades there has been a decrease in early
successional habitat due to reforestation of the eastern United States,
development, and changes in agricultural practices. The petition claims
that the golden-winged warbler now breeds within a matrix of human-
developed landscape (urban/suburban development, agriculture, and
reforestation practices), thus leading to its decline in what was
historically viable breeding habitat (Petition, p. 12;
NatureServe2010).
The petition also claims that golden-winged warblers now rely on
human interference to create early successional habitat that consists
of shrubs, open canopy, habitats with forested edge, and/or grassy
patches (Petition, p. 12; Klaus and Buehler 2001). The petition claims
that in the United States, the decline in availability of habitat used
by golden-winged warblers and other early successional habitat-
dependent species (such as grassland birds) is increasingly becoming a
concern (Petition, p. 13; Motzkin and Foster 2004). Although the
petition (Petition, p. 14) states that habitat modification or loss is
the primary obstacle for golden-winged warbler stabilization, Confer et
al. (2003) state that other factors must be involved in population
declines, because in areas where ample suitable habitat exists, such as
in Massachusetts, the warblers have become extirpated;.
Evaluation of Information Provided in the Petition and Available in
Service Files
Information provided by the petitioner and readily available in our
files indicates the golden-winged warbler may be declining rangewide
due to loss, degradation, and modification of early successional
habitat. Forest maturation, land development, wetland destruction and
loss, and lack of natural events that create viable breeding sites
contribute to the reduction of available nesting habitat (Buehler et
al. 2006, p. 1; Buehler et al. 2010, p. 118).
In the north-central breeding range, long-term trends (1966-2007)
estimate populations to be decreasing by 1.4 percent per year (Sauer et
al. 2008, not paginated). In this breeding region, Minnesota,
Wisconsin, and Michigan together hold approximately 69 percent of the
global breeding population of golden-winged warblers (Buehler et al.
2010, p. 31). Long-term trends (1966-2007) for Michigan estimate a
population decline of 8.1 percent per year, with numbers relatively
stable in Minnesota and Wisconsin. In the north-central breeding range,
nests are found in wetland and upland shrub habitats consisting of old
fields and pastures, clearcuts, and regenerating aspen tracts. The
major threats to populations in the north-central breeding range
include habitat loss, wetland drainage, and habitat succession (Buehler
et al. 2010, p. 35).
In Canada (Manitoba, Ontario, Quebec, and Saskatchewan), long-term
Breeding Bird Survey (BBS) data from 1966-2007 (Buehler et al. 2007, p.
144; Sauer et al. 2008, not paginated) indicate a relatively stable
breeding population. This region supports approximately 18.2 percent of
the global breeding population. Limited, short-term data collected over
the last 10 years suggest a 4 percent per year population decline
(Sauer et al. 2008, p. 1). More data are needed to accurately predict
population trends for this region.
The Northeast supports 11 percent of the total global breeding
population (Buehler et al. 2010, p. 74). In this breeding range, long-
term trend information (1966-2007) from BBS data indicates an 8.8
percent per year decline in populations. More recent data from the past
25 years (1980-2007) estimate the same negative trend, at a loss of 6.2
percent per year (Sauer et al. 2008, p.1). Loss of early successional
habitat and fragmentation of existing habitat contribute to the decline
of populations in the Northeast region. Tens of millions of hectares of
habitat has been lost as abandoned farmland passes through early
successional to late successional stages (Confer et al. 2003, p. 142).
This advancement in forest succession is taking place in many areas of
the Northeast. Forest regeneration without regular natural disturbance,
such as fire, results in dense canopy lacking open patches and low
shrub layers. Landscapes with these characteristics are structurally
different than forests that are regularly undergoing natural
disturbance (Buehler et al. 2010, p. 118), and these dense forest
habitats do not support golden-winged warblers. In the Northeast
breeding range specifically, close associations with the blue-winged
warbler (Vermivora cyanoptera) could also be contributing to the
decline of golden-winged warblers. Breeding golden-winged warbler pairs
in the Northeast overlap with blue-winged warbler breeding pairs, and
these interactions can lead to golden-winged warblers either being
pushed out of territories or to hybridization between the two species.
More research is needed to understand if these interspecific
interactions may be a threat to the golden-winged warbler (golden-
winged and blue-winged warbler hybridization is discussed under factor
E (Other natural or manmade factors affecting its continued existence).
In the southeastern breeding range, populations are too low to
estimate decade-long trends; however, long-term trend information
(1966-2007) from BBS data indicate a 7.3 percent decline per year
(Sauer et al. 2008, p. 1). This region only supports 1.4 percent of the
global breeding population (Buehler et al. 2010, p. 58). Research
indicates that the decline of early successional habitat has led to the
extirpation of golden-winged warblers in the southern districts of
Cherokee National Forest, Tennessee (Klaus et al. 2005, p. 232). In
areas of hardwood forests previously occupied by breeding pairs, early
successional habitat has declined because of the occurrence of natural
forest succession without the intervention of forest harvest or natural
disturbance (Klaus et al. 2005, p. 232). Habitat loss may be the cause
of population declines in the southeastern breeding range, because
other potential threats such as blue-winged warbler interactions are
not as common in this region.
Deforestation events have increased in golden-winged warbler
wintering grounds, specifically the montane oak forests in Central and
South America (Buehler et al. 2007, p. 4). The population dynamics of
golden- and blue-winged warblers on wintering grounds lends support to
the assertion that interspecific competition does not appear to be
occurring in this region. Golden-winged warblers occupy areas that are
further south and mostly separated from those of blue-winged warblers,
with limited overlap occurring in northern Panama, Costa Rica,
Honduras, Nicaragua, and Guatemala (Confer 1992, not paginated; Buehler
et al. 2010, p. 120). Although it is unclear if the loss of
overwintering habitat affects survival, overall golden-winged warbler
population declines may be related. Potential threats to the species on
wintering grounds need to be examined to determine if changes in
wintering habitat are limiting to golden-winged warbler population
viability.
The degradation of migratory stopover sites could impact fitness of
individuals, or more directly cause mortality
[[Page 31924]]
(Buehler et al. 2010, p. 120). Other anthropogenic factors could impact
individuals along migratory routes or at stopover sites. One report
compiled data from 47 studies that monitored bird strikes at
communication towers and found that golden-winged warbler mortality was
identified at 15 towers, which accounted for 542 individuals (Shire et
al. 2000, p.8).
BBS data indicate that the golden-winged warblers' breeding range
has been shifting for the last 150 years and population numbers have
declined (Confer et al. 2003, p. 142; Sauer et al. 2008, p. 1; Buehler
et al. 2010, p. 24). Breeding populations in other States may become
extirpated (Connecticut, South Carolina, Georgia, Indiana, Illinois,
and Rhode Island) (Confer 1992, not paginated; Buehler et al. 2010, p.
25) and, already, the golden-winged warbler has not been verified to be
breeding in Massachusetts (USGS North American Breeding Bird Atlas
Explorer).
Golden-winged warblers require specific habitat characteristics
found in early successional landscapes for nesting, and loss of this
habitat may continue to reduce populations by limiting fecundity and,
therefore, reproductive success, leading to population declines. In
general, we expect golden-winged warbler populations to continue to
decline, as a response to the reduction in breeding areas due to
destruction, modification, and curtailment of early successional
habitats. Loss of overwintering habitat and degradation of migratory
stopover sites may also contribute to continuing population declines by
reducing survival or reducing overall fitness, which can translate to
reduced fecundity.
Summary of Factor A
In summary, the petition and information in our files identifies
the loss of early successional habitat by changes in agricultural
practices, forest maturation, land development, wetland destruction and
loss, and lack of natural disturbance events as potential threats to
the golden-winged warbler. Furthermore, winter habitat is affected by
increasing deforestation and migrating individuals are impacted by the
increasing number of communication towers. Therefore, we find that the
information provided in the petition, as well as other information
readily available in our files, presents substantial scientific or
commercial information to indicate that the golden-winged warbler may
warrant listing due to the present or threatened destruction,
modification, or curtailment of the species' habitat or range.
B. Overutilization for Commercial, Recreational, Scientific, or
Educational Purposes.
Information Provided in the Petition
The petition did not present any information with respect to Factor
B.
Evaluation of Information Provided in the Petition and Available in
Service Files
The information in our files does not indicate any threat to
golden-winged warbler due to overutilization for commercial,
recreational, scientific, or educational purposes. Therefore, we find
that the petition and information readily available in our files does
not provide substantial scientific or commercial information to
indicate that the overutilization for commercial, recreational,
scientific, or educational purposes may present a threat to the golden-
winged warbler such that the petitioned action may be warranted.
However, we will further investigate the potential threat of
overutilization for commercial, recreational, scientific, or
educational purposes in our status review for this species.
C. Disease or Predation
Information Provided in the Petition
The petition did not present any information with respect to Factor
C.
Evaluation of Information Provided in the Petition and Available in
Service Files
Our files indicate that, although nest predation may be a leading
cause of nest loss for golden-winged warblers, there is not enough data
indicating that nest predation rates are limiting factors in population
declines (Buehler et al. 2010, p. 125). Therefore, the information in
our files does not indicate any threat to golden-winged warblers due to
disease or predation. We find that the petition and information readily
available in our files do not provide substantial scientific or
commercial information to indicate that disease or predation may
present a threat to the golden-winged warbler such that the petitioned
action may be warranted. However, we will further investigate the
potential threat of disease or predation in our status review for this
species.
D. The Inadequacy of Existing Regulatory Mechanisms
Information Provided in the Petition
The petition claims that the only way to ensure protection for the
golden-winged warbler is to mandate Federal protection across the
species' entire North and South America range (Petition, pp. 22-23).
The petition suggests that existing regulatory mechanisms do not
adequately protect the golden-winged warbler. State regulations provide
the species protection from only the sale or take of individuals; in
addition, State regulations are insignificant because they protect the
species at localized areas only, versus the entire range, and do not
address habitat protection or conservation (Petition, pp. 16-23).
Evaluation of Information Provided in the Petition and Available in
Service Files
In Canada, golden-winged warblers are protected under the Migratory
Bird Convention Act of 1916 and by the Schedule One of Canada's Species
at Risk Act. The Committee of the Status of Endangered Wildlife in
Canada (COSEWIC) lists the bird as threatened in Quebec, Ontario, and
Manitoba. In the United States, under the Migratory Bird Treaty Act of
1918, as amended, it is unlawful to take, capture, kill, or possess
migratory birds, their nests, eggs, and young. These protections extend
to the golden-winged warbler. The Service has identified the golden-
winged warbler nationally as a Bird of Conservation Concern, which is a
designation assigned to the species by the Division of Migratory Bird
Management. This designation indicates that the species is one which,
without additional conservation actions, is likely to become a
candidate for listing under the Act.
The Service also identifies the species as a bird of management
concern at the Bird Conservation Region (BCR) scale (developed by the
North American Bird Conservation Initiative) in regions 12 (Boreal
Hardwood Transition Zones), 13 (Lower Great Lakes/St. Lawrence Plain),
23 (Prairie Hardwood Transitions Zones), and 28 (Appalachian Mountains)
(Service 2008, pp. 28, 29, 39, 44). Partners in Flight ranks the
golden-winged warbler as a Watch List Species in need of immediate
management action (Buehler et al. 2010, p. 127 cited from Rich et al.
2004). The golden-winged warbler is listed as a Species of Global
Concern on the Audubon Society's species watch list (The National
Audubon Society, not paginated). The International Union for
Conservation of Nature (IUCN) lists golden-winged warblers as Near
Threatened on their Global Continental Conservation Status list
(BirdLife International 2008). These various classifications, however,
are not regulatory in nature.
[[Page 31925]]
The golden-winged warbler is State-listed as threatened,
endangered, or of special concern in some areas of its range.
Regulatory protections for State-listed species vary by individual
States, but in general, State-listed species do not receive the same
level of protection, especially with regard to habitat loss, afforded
to Federally listed species. The Service is leading a cooperative
effort with Federal and State agencies, researchers, universities and
other nongovernment organizations to determine the extent of threats to
the golden-winged warbler population. Developed in 2003, the Golden
Winged Warbler Working Group consists of Federal, State, and nonprofit
entities. The Working Group prioritizes research and monitoring
activities, investigates hybridization range and species genetics,
develops habitat classification measures and management priorities, and
works with the Natural Resource Conservation Service (NRCS, U.S.
Department of Agriculture) to integrate species-specific management
into legislation such as the Farm Bill (Buehler et al. 2007, p. 1442).
The working group conducts a variety of conservation efforts and
research throughout the species' range. These collaborative efforts
were initiated separately from the petition for listing this species
under the Act, and solely because of the interest of the cooperating
organizations in improving the status of this species, which is widely
recognized as a species of conservation concern.
Summary of Factor D
The petition and information in our files suggest that individual
State-level protections are not adequately protecting the warbler, as
evidenced by declining population trends in all breeding areas and
declining habitat trends on the wintering grounds. In addition, the
existing regulatory mechanisms do not provide habitat conservation or
protection measures, nor do they directly address management incentives
for the golden-winged warbler. The formation of the Golden Winged
Warbler Working Group is leading the development of conservation
initiatives; however, this group does not have authority to implement
wide-scale population-level protection. Declining population trends in
all breeding areas, as well as declining habitat trends on the
wintering grounds of golden-winged warbler, continue, and existing
legislation does not protect the golden-winged warbler or its habitat
throughout the species' range. Therefore, we find that the information
provided in the petition, as well as other information readily
available in our files, presents substantial scientific or commercial
information to indicate that the golden-winged warbler may warrant
listing due to the inadequacy of existing regulatory mechanisms.
E. Other Natural or Manmade Factors Affecting Its Continued Existence.
Interactions With Blue-Winged Warbler
Information Provided in the Petition
The petition claims that golden-winged warblers are being displaced
by the expansion of blue-winged warblers, resulting in golden-winged
warblers being pushed north into Ontario and west into Minnesota
(Petition, p. 15; Hamel et al. 2005). The expansion of blue-winged
warblers into golden-winged warblers' habitat may be correlated with
loss of early successional habitat (Petition, p. 15; NatureServe 2010).
The range of the golden-winged and blue-winged warblers overlap
considerably, and data from one study found that golden-winged warblers
nesting near blue-winged warblers laid fewer eggs (Petition, p. 15;
Confer et al. 2003, p. 141).
Evaluation of Information Provided in the Petition and Available in
Service Files
Data from the last 150 years document the replacement of golden-
winged warblers with blue-winged warblers in areas of the Northeast
(Buehler et al. 2010, p. 75). The expansion of blue-winged warblers may
result in the displacement of golden-winged warblers, a decrease in
productivity, or an increase in hybridization events (Confer et al.
2003, p. 141; Buehler et al. 2010, p. 121).
The golden-winged warbler is closely related to the blue-winged
warbler, and interbreeding between the two species occurs, producing
fertile young (Confer 1992, not paginated; Buehler et al. 2010, p. 5).
The two hybrids that can result from the cross-mating of the two
species are Brewster's warbler and Lawrence's warbler. The Brewster's
warbler is a first-generation hybrid, meaning a cross between golden-
winged and blue-winged parents. It holds the dominate traits of both
parents (white ventral plumage of the golden-winged warbler but overall
coloration of the blue-winged warbler). Brewster's hybrids can back-
cross with golden-winged or blue-winged warblers to produce viable
offspring (Gough and Sauer 1997, not paginated). The Lawrence's warbler
is a cross between a Brewster's warbler and a golden-winged warbler, or
a Brewster's warbler and a blue-winged warbler. The Lawrence's warbler
displays the recessive traits (feather coloration of the golden-winged,
with yellow plumage of the blue-winged) (Gough and Sauer 1997, not
paginated; Buehler et al. 2010, p. 5).
The population-level impacts of interactions between golden-winged
and blue-winged warblers, and variables contributing to hybridization
events, are unclear. In two hybridization zones, nest success rates for
the golden-winged warbler were lower in New York at sites that had
documentation of species hybridization compared to sites in North
Carolina that had no evidence of hybridization (Klaus and Buehler 2001,
p. 300). This suggests that in areas where the two species occur
together, reproductive efforts of golden-winged warblers may be
suppressed due to hybridization. However, in New York there are areas
of overlap where the two species are sympatric and co-exist without
detected impacts to golden-winged warbler productivity (Confer and
Larkin 1998, p. 213).
The degree of hybridization may vary within different geographic
locations. For example, interspecific interactions between blue-winged
and golden-winged warblers may be more pronounced in the northeastern
United States, where populations overlap considerably (Buheler et al.
2010, p. 118). In upland areas of New York and Pennsylvania, golden-
winged warblers might be limited by habitat loss in addition to blue-
winged warbler hybridization, while populations in North Carolina may
be limited only by habitat loss (Buehler et al. 2007, p. 1440). In some
areas of the southeastern United States, the golden-winged warbler
population has declined in the absence of blue-winged warblers (Buheler
et al. 2010, p. 121). Therefore, other factors likely contribute to
declines of golden-winged warbler populations in the southeastern
breeding range.
More research is needed to fully understand the possible effects of
hybridization on the golden-winged warbler. The information in the
petition and in Service files provides limited data on golden-winged
and blue-winged warbler interactions. We find the information provided
in the petition discusses one possible threat, the possible reduction
of golden-winged warbler productivity due to blue-winged warblers
occupying golden-winged warbler breeding sites. Information in Service
files indicates that interspecific interactions, such as species
hybridization, may be a threat to the golden-winged warbler, especially
in
[[Page 31926]]
specific geographic locations. Both the petition and Service files
recognize that blue-winged warblers are expanding into golden-winged
warblers' range and that this expansion could be correlated with the
loss of early successional habitat. Although the effects of
interspecific interactions (reduced breeding productivity or
hybridization) between the blue-winged and golden-winged warbler remain
unclear, we find that the information provided in the petition, as well
as other information readily available in our files, presents
substantial scientific or commercial information to indicate that the
golden-winged warbler may warrant listing due to other natural or
manmade factors affecting the species' continued existence due to these
factors.
Brown-headed Cowbird Nest Parasitism
Information Provided in the Petition
The petition states that brown-headed cowbirds (Molothrus ater) are
parasitizing golden-winged warbler nests, with evidence suggesting that
the rate of parasitism reduces fledgling success (Petition, p. 15). The
study cited in the petition was conducted in New York and found a 50
percent loss in fledgling success in nests with brown-headed cowbird
eggs. However, the small sample size of nests (34 nonparasitized nests
and 7 parasitized nests) may lead to statistical error (Confer et al.
2003, p. 141). This study found that fledgling rate in nonparasitized
nests was high (68 percent), while fledgling rate in parasitized nests
was low (32 percent), and that this difference is enough to warrant
concern about brown-headed cowbird parasitism limiting golden-winged
warbler fledgling success (Confer et al. 2003, p. 141). The petition
concludes that nest parasitism, coupled with other factors, leads to
reduced fledgling success (Petition, p. 15).
Evaluation of Information Provided in the Petition and Available in
Service Files
The rate of cowbird parasitism varies within the range of golden-
winged warblers. Golden-winged warbler nests, especially in
agricultural landscapes, experience moderate rates of parasitism
(Confer 1992, not paginated). In a sample size of nests found in the
eastern United States, central Michigan, central New York, and eastern
New Jersey, 11 of 113 nests were parasitized (Coker and Confer 1990, p.
551). In nests found in New York, from 1988 to 1994, 30 percent had at
least one cowbird egg or chick, which reduced fledgling success by 17
percent (Confer et al. 2003, p. 138). Although brown-headed cowbirds
were present, cowbird parasitism was not recorded in nests of golden-
winged warblers in areas of Tennessee and North Carolina (Klaus and
Buehler 2001, p. 29) and was not apparently impacting golden-winged
populations in West Virginia or Ontario (Buehler et al. 2010, p. 23).
At breeding sites in north central New York, cowbird parasitism was
correlated with a reduction in incubated eggs and a reduction in the
proportion of incubated eggs that hatched; however, parasitism did not
significantly affect nestling success rate (Confer et al. 2003, p.
138).
Although there is evidence indicating golden-winged warblers are
susceptible to brown-headed cowbird parasitism, it has not yet been
determined if brown-headed cowbird parasitism has a substantial impact
on golden-winged warbler nest success rates throughout the species'
breeding range. Brown-headed cowbird parasitism may be a greater
concern for warblers nesting in the northeast United States, compared
to warblers in the north central breeding range.
We find that, based on information in the petition, as well as
other information readily available in our files, we are unsure of the
impact cowbird parasitism may have on the golden-winged warbler.
However, we will further investigate the potential impacts of cowbird
parasitism in our 12-month status review.
Finding
On the basis of our analysis under section 4(b)(3)(A) of the Act,
we determine that the petition presents substantial scientific or
commercial information indicating that listing the golden-winged
warbler throughout its entire range may be warranted. This finding is
based on information provided under Factors A (present or threatened
destruction, modification, or curtailment of the species' habitat or
range), D (the inadequacy of existing regulatory mechanisms), and E
(other natural or manmade factors affecting the species' continued
existence). Specifically, we find that the following may pose threats
to the golden-winged warbler throughout all or a significant portion of
its range, such that the petitioned action may be warranted: Habitat
modification and loss of early successional habitat (Factor A);
inadequacy of existing regulatory mechanisms (because existing
regulations only provide protection from the sale or take of
individuals at localized areas, rather than the entire range, and do
not address habitat protection or conservation) (Factor D); and
interactions with blue-winged warblers (Factor E). We determine that
the information provided under Factors B (overutilization for
commercial, recreational, scientific or educational purposes) and C
(disease or predation) is not substantial.
Because we have found that the petition presents substantial
information indicating that listing the golden-winged warbler may be
warranted, we are initiating a status review to determine whether
listing the golden-winged warbler under the Act is warranted.
The ``substantial information'' standard for a 90-day finding
differs from the Act's ``best scientific and commercial data'' standard
that applies to a status review to determine whether a petitioned
action is warranted. A 90-day finding does not constitute a status
review under the Act. In a 12-month finding, we will determine whether
a petitioned action is warranted after we have completed a thorough
status review of the species, which is conducted following a
substantial 90-day finding. Because the Act's standards for 90-day and
12-month findings are different, as described above, a substantial 90-
day finding does not mean that the 12-month finding will result in a
warranted finding.
References Cited
A complete list of references cited is available on the Internet at
http://www.regulations.gov and upon request from the Wisconsin
Ecological Services Office (see FOR FURTHER INFORMATION CONTACT).
Author
The primary authors of this notice are the staff members of the
Wisconsin Ecological Services Office (see FOR FURTHER INFORMATION
CONTACT).
Authority: The authority for this action is the Endangered
Species Act of 1973, as amended (16 U.S.C. 1531 et seq.).
Dated: May 4, 2011.
Rowan W. Gould,
Acting Director, U.S. Fish and Wildlife Service.
[FR Doc. 2011-13731 Filed 6-1-11; 8:45 am]
BILLING CODE 4310-55-P
