[Federal Register: December 6, 2006 (Volume 71, Number 234)]
[Proposed Rules]               
[Page 70717-70733]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]



Fish and Wildlife Service

50 CFR Part 17

Endangered and Threatened Wildlife and Plants; 12-Month Finding 
on a Petition To List the Cerulean Warbler (Dendroica cerulea) as 
Threatened With Critical Habitat

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Notice of a 12-month petition finding.


SUMMARY: We, the U.S. Fish and Wildlife Service (Service), announce a 
12-month finding on a petition to list the cerulean warbler (Dendroica 
cerulea) as threatened under the Endangered Species Act of 1973, as 
amended (Act). The petition also asked that critical habitat be 
designated for the species. After reviewing the best available 
scientific and commercial information, we find that the petitioned 
action is not warranted. We ask the public to submit to us any new 
information that becomes available concerning the status of, or threats 
to, the species. This information will help us monitor and encourage 
the conservation of this species.

DATES: The finding announced in this document was made on November 28, 

ADDRESSES: Comments and materials received, as well as supporting 
documentation used in the development of this 12-month finding, will be 
available for inspection, by appointment, during normal business hours 
at the Columbia Ecological Services Field Office, 101 Park DeVille 
Drive, Suite A, Columbia, Missouri 65203. Submit new information, 
materials, comments, or questions concerning this species to the 
Service at the above address.

FOR FURTHER INFORMATION CONTACT: Charles Scott, Supervisor (see 
ADDRESSES), by telephone at 573-234-2132, by facsimile at 573-234-2181, 
or by electronic mail at charlie_scott@fws.gov. Individuals who are 
hearing-impaired or speech-impaired may call the Federal Relay Service 
at 1-800-877-8339 for TTY assistance.



    Section 4(b)(3)(B) of the Endangered Species Act of 1973, as 
amended (16 U.S.C. 1531 et seq.), requires that, for any petition to 
revise the Lists of Endangered and Threatened Wildlife and Plants that 
contains substantial scientific or commercial information that the 
petitioned action may be warranted, we make a finding within 12 months 
of the date of the receipt of the petition on whether the petitioned 
action is: (a) Not warranted, (b) warranted, or (c) warranted, but that 
the immediate proposal of a regulation implementing the petitioned 
action is precluded by other pending proposals to determine whether any 
species is threatened or endangered, and expeditious progress is being 
made to add or remove qualified species from the List of Endangered and 
Threatened Species. Such 12-month findings are to be published promptly 
in the Federal Register. Section 4(b)(3)(C) of the Act requires that a 
petition for which the requested action is found to be warranted but 
precluded shall be treated as though resubmitted on the date of such 
finding, requiring a subsequent finding to be made within 12 months.

Previous Federal Actions

    We added the cerulean warbler to our former Category 2 list of 
candidate species on November 21, 1991 (56 FR 58804). Category 2 
candidate species were those species for which we possessed data 
indicating that proposing to list them as endangered or threatened was 
possibly appropriate, but for which conclusive data on biological 
vulnerability and threat were not available at that time to support 
proposed rules. Category 1 candidate species were those for which we

[[Page 70718]]

possessed sufficient information on biological vulnerability and 
threats to support proposals to list them as endangered or threatened 
species. The cerulean warbler was also in the November 15, 1994, 
Candidate Notice of Review (59 FR 58982) as a Category 2 candidate 
species. The list of Category 2 species was eliminated by the Service 
in 1996. Since then the Service has applied the term ``candidate 
species'' only to those species previously considered to be ``Category 
1'' candidates, and we apply the same definition to these species (61 
FR 7596; February 28, 1996). The cerulean warbler has never been a 
Category 1 candidate species or a candidate species, as defined, since 
    Due to concerns regarding the population trend of the species, in 
1995, the Service contracted to Dr. Paul Hamel, of the U.S. Forest 
Service's Southern Forest Research Station in Stoneville, Mississippi, 
to develop a cerulean warbler rangewide status assessment report. Dr. 
Hamel completed his report in April of 2000 (Hamel 2000a), and we 
distributed it and posted it on our Web site at that time.
    On November 6, 2000, the Service received an October 30, 2000, 
letter from Douglas A. Ruley of the Southern Environmental Law Center 
in Asheville, North Carolina. Mr. Ruley's letter conveyed a petition to 
list the cerulean warbler as a threatened species and to designate 
critical habitat for the species (Ruley 2000). The following 
organizations were listed as the petitioners: National Audubon Society, 
Defenders of Wildlife, Sierra Club, The Wilderness Society, American 
Lands Alliance, Western North Carolina Alliance, Southern Appalachian 
Biodiversity Project, Appalachian Voices, Cherokee Forest Voices, 
Southern Environmental Law Center, Southern Appalachian Forest 
Coalition, Heartwood, Dogwood Alliance, West Virginia Highlands 
Conservancy, Inc., Virginia Forest Watch, Buckeye Forest Council, 
Allegheny Defense Project, Vernon Civic Association, Conservation 
Action Project, Superior Wilderness Action Network, Indiana Forest 
Alliance, Regional Association of Concerned Environmentalists, Ouachita 
Watch League, Newton County Wildlife Association, Chattooga 
Conservancy, Wild Alabama, Georgia Forest Watch, and South Carolina 
Forest Watch.
    On September 24, 2002, the Service made its initial 90-day finding 
on the petition, and a notice of that finding was published in the 
Federal Register on October 23, 2002 (67 FR 65083). Our finding was 
that the petition presented substantial information indicating that the 
petitioned action of listing the species may be warranted. At that 
time, we initiated a status review, which included a 90-day comment 
    We received 290 responses to our request for additional information 
in our 90-day finding for the cerulean warbler (67 FR 65083; October 
23, 2002). A large number of these responses were identical or similar 
comments. Comments and information were received from 12 State fish and 
wildlife agencies within the range of the warbler, 4 academic 
researchers, 2 county government agencies, the U.S. Forest Service (4 
units), National Park Service (2 units), Department of Defense, U.S. 
Army Corps of Engineers, a U.S. Congressman, 7 corporations, 40 
nongovernmental organizations, numerous private citizens, and several 
other entities. Additionally, we directly contacted, and received 
information from, wildlife agencies and biologists within the cerulean 
warbler's range in Canada and South America. We reviewed all responses 
received, and those that contained new, updated, or additional 
scientific or commercial data were thoroughly considered in this 12-
month finding.
    Due to budget shortfalls during subsequent fiscal years, the 
Service was unable to fund additional work on the petition until late 
in fiscal year 2005. Since that time, we have analyzed the comments 
received after the 2002 finding, reviewed new published and unpublished 
reports and data on the species and factors affecting its habitat, and 
brought together a panel of experts on the species to provide 
additional insight into the current status and trends of the cerulean 
    After our resumption of work on the petition in late 2005, a 
lawsuit was filed by five of the petitioners (National Audubon Society, 
Defenders of Wildlife, Southern Appalachian Biodiversity Project, 
Western North Carolina Alliance, and Heartwood) in the U.S. District 
Court for the District of Columbia on February 28, 2006. The suit asked 
the Court, among other things, to compel the Service to make and 
publish in the Federal Register a 12-month finding regarding the 
plaintiffs' petition to list the cerulean warbler as a threatened 
species. Although we had already resumed work on the petition, due to 
the lawsuit, we entered into a settlement agreement with plaintiffs in 
which we agreed to provide our 12-month finding to the Federal Register 
no later than November 30, 2006.

Cerulean Warbler Natural History

    The cerulean warbler is a small insectivorous neotropical migrant 
songbird (11.5 centimeters (4.5 inches) long and weighing 8 to 10 grams 
(0.3 to 0.4 ounces)). It breeds in mature deciduous forests primarily 
within the central hardwood region of eastern North America, primarily 
in the Ohio and Mississippi River Valleys and adjacent areas east of 
the Appalachians, in New England and southern Canada, and in the Great 
Lakes region. (Hamel 2000a, pp. 2-4). The breeding range generally 
extends from the eastern Great Plains, north to Minnesota, east to 
Massachusetts, and south to North Carolina and Louisiana (Hamel 2000a, 
p. 2), encompassing 33 States and 2 Canadian Provinces. The core area 
of the breeding range is currently within the Cumberland Plateau and 
Ohio Hills physiographic regions in eastern Tennessee, eastern 
Kentucky, southern and western West Virginia, southeastern Ohio, and 
southwestern Pennsylvania (Villard and Mauer 1996, p. 7 and Figure 7; 
Sauer et al. 2005a). This species undertakes a long migration compared 
to many other warblers and passerines of similar size (Hamel 2000b, p. 
1), covering a distance of approximately 4,000 kilometers (km) (2,500 
miles (mi)) between the central latitudes of North America and northern 
latitudes of South America. The migratory pathway between the breeding 
and wintering grounds is not well known, but for most individuals, it 
likely includes a flight across the Gulf of Mexico and stops at a 
limited number of locations in Central America and northern Colombia or 
Venezuela (Hamel 2000b, p. 4). The fall migration to South America 
might be along a more easterly path than that of the northward 
migration in the spring (Dunn and Garrett 1997, p. 405). Cerulean 
warblers winter in broad-leaved evergreen forests within a relatively 
narrow band of middle elevations (500 to 1,800 meters (m); 1,650 to 
5,900 feet (ft)) in the northern Andes Mountains in Venezuela, 
Colombia, Ecuador, Peru, and Bolivia and possibly in the Guayana 
Highlands of southeastern Venezuela, especially the tabletop mountains 
(tepuis) of this ecoregion (Robbins et al. 1992, p. 559; Moreno et al. 
2006 unpublished report, p. 3).
    On the breeding grounds, cerulean warblers prefer mature hardwood 
forests with tall, large-diameter trees and a structurally diverse 
canopy (multiple vegetation layers, often associated with uneven-aged 
forest stands). They occupy forests with these structural 
characteristics in both upland and

[[Page 70719]]

bottomland locations (Hamel 2000b, p. 4). In the Appalachian Mountains, 
they tend to occur more frequently and in higher abundance on ridge 
tops than in valley bottoms (Weakland and Wood 2005, pp. 503-504; Wood 
et al. 2006, pp. 160-161; Buehler et al. in press, p. 9). Throughout 
much of their breeding range, they prefer to breed in large forest 
patches, and so are considered ``area-sensitive'' (Robbins et al. 
1989a, p. 25; Mueller et al. 2000, p. 15), although they might not be 
as sensitive to forest patch size in well-forested and less fragmented 
landscapes where avian nest predation and parasitism rates tend to be 
lower (Hamel 2000b, p. 4). In parts of their range, cerulean warblers 
exhibit positive associations with canopy gaps and relatively small 
internal forest openings (Perkins 2006, p. 26), but they avoid abrupt 
edges between forest and large areas of open land (Wood et al. 2006, p. 
160). Post-fledging habitat for this species has not been studied, but 
assuming cerulean warblers are similar to other mature forest-
associated birds, they might seek out areas where shrubby vegetation 
provides good cover from predators as well as an abundance of good 
foraging substrate. Such areas might include small forest openings or 
early successional habitats, but habitat use during this period of the 
year has not been described and the relative importance of different 
habitat types during the post-fledging period is not known.
    Insects are the primary food source of cerulean warblers throughout 
the year. During the breeding season, their diet has been observed to 
consist primarily of Homoptera and Lepidoptera but also may include 
small amounts of Coleoptera, Hymenoptera, Diptera, Hemiptera, Araneae, 
and other arthropods (Hamel 2000b, p. 6). While no detailed studies of 
diet have been completed during the non-breeding period, cerulean 
warblers appear to use nectar resources, as well as insects, during at 
least some period of their residency on their non-breeding grounds in 
South America (Jones et al. 2000, p. 961; USFWS 2006, Appendix 5--M.I. 
Moreno's PowerPoint presentation, slide 15) and have also been observed 
eating small amounts of plant material during migration (Hamel 2000b, 
p. 5). Their primary foraging mode for capturing insects is gleaning 
prey from the upper and lower surfaces of leaves. They also use 
sallying and hover-gleaning to a lesser extent (Hamel 2000b, p. 5).
    Cerulean warblers build their nests high above ground (mean height 
of 11.4 m (37 ft); Hamel 2000b, p. 9) in the mid-story or canopy of 
trees. Clutch size is normally 3 or 4 eggs with an incubation period of 
11 to 12 days and a nestling period of 10 to 11 days. Their nests are 
known to be parasitized by brown-headed cowbirds, particularly in the 
western portion of the cerulean warbler breeding range where cowbirds 
are more abundant (Hamel 2000b, pp. 9-11). Nest success varies annually 
and regionally, with observed average annual nest success rates at 
specific study sites ranging from approximately 20 percent in southern 
Indiana and the lower Mississippi River valley to approximately 58 
percent in Ontario and eastern Tennessee. The average number of young 
fledged per successful nest also varies, although somewhat less 
dramatically, with reports of annual values between 1.7 and 3.0 for 
most study sites (USFWS 2006, Appendix 5--D. Buehler's PowerPoint 
presentation, slides 25-28). Cerulean warblers typically arrive on 
their breeding grounds between mid-April and mid-May, depending on 
latitude, and remain there until sometime between late July and mid-
September (Dunn and Garrett 1997, pp. 405-406). Cerulean warblers 
usually raise a single brood during this period; multiple nesting 
attempts are commonly undertaken if initial nest attempts fail. It is 
rare for this species to raise two broods in the same breeding season.
    Cerulean warblers are predominantly socially monogamous (one male 
mated with one female), but social bigamy (one male mated with two 
females) has been observed in the Ontario population (USFWS 2006, 
Appendix 4, Day 2-p. 2). This behavior has not been studied at other 
locations. Some researchers have also observed a clumped distribution 
of cerulean warbler territories within study sites, apparently 
independent of habitat features. However, these patterns have not been 
studied rigorously nor confirmed as being different from a random 
distribution or a result of habitat selection (Hamel 2000b, p. 8).
    Analysis of genetic variability at the population level has 
revealed no significant variation in neutral genetic markers across the 
breeding range, suggesting a single genetic population for this species 
(Veit et al. 2005, pp. 165-166). A study of natal and breeding 
dispersal between years using stable isotope analysis corroborates this 
hypothesis by suggesting a relatively high level of interannual adult 
dispersal between regions, particularly within the central portions of 
the breeding range (USFWS 2006, Appendix 4, Day 1--p. 14). Adult 
dispersal to different breeding locations between years appears to be 
lower in both the southern and northern portions of the range than in 
the center of the range, suggesting higher site fidelity to breeding 
locations in those portions of the range. Natal dispersal between 
regions within the breeding range did not appear to be any more 
pronounced than adult dispersal. This is different than many other 
warbler species, which typically exhibit much higher natal dispersal 
than adult dispersal. Dispersal characteristics of cerulean warblers 
probably influence source-sink dynamics of the population, and more 
information on dispersal is needed to understand the current population 
trend of the species.
    On the wintering grounds, this species may prefer forests with old-
growth conditions, but it has also been found in second-growth forests 
and shade-grown coffee plantations (Hamel 2000b, p. 5; Jones et al. 
2000, p. 958). As with its breeding habitat, a structurally diverse 
canopy with multiple vegetation layers appears to be an important 
component of its wintering habitat. It is generally found in mixed-
species flocks of canopy-dwelling birds, and this association with 
mixed-species flocks could be an important characteristic of their 
occurrence on the wintering grounds (Hamel 2000b, p. 5), although more 
study of their social behavior is needed. Cerulean warblers usually 
reside on their winter grounds from October to February (Hamel 2000b, 
p. 9--Figure 3).
    Cerulean warblers are nocturnal migrants. Little is known about 
habitat preferences and other ecological aspects of this bird's 
migration. Several stop-over locations for spring migration have been 
found in Belize (Parker 1994, p. 70), Honduras, and Guatemala (Welton 
et al. 2005, p. 1), but records of this species during migration 
elsewhere are scarce. To explain this, one hypothesis is that cerulean 
warblers could migrate in pulses of large groups of individuals that 
make relatively long flights between stops (for example, northern South 
America to middle Central America and then across the Gulf of Mexico to 
southern United States). Even fewer records exist for cerulean warblers 
during the southward migration in the fall, prompting the suggestion 
that these birds might fly non-stop from the southern U.S. all the way 
to the northern coast of South America. Isotope analyses indicate some 
level of migratory connectivity for this species (USFWS 2006, Appendix 
4, Day 2--pp. 7-8), suggesting that individuals residing in the 
northern portions of the breeding range tend to go to more northerly 
portions of the wintering range and birds from the southern portions of 
the breeding range go to the

[[Page 70720]]

more southerly portions of the wintering range.
    Survival rates of cerulean warblers have not been studied widely 
across their range. Only one study has published estimates of minimum 
survival rates. Jones et al. (2004, p. 17) reported an annual adult 
male survival rate of 0.49 over the period 1995 to 2001; or 0.54 in 
``normal years'' and 0.40 following an ice storm in 1998. These 
estimates are minimum values because they do not account for adult 
dispersal and emigration between breeding seasons.

Population Size and Trends

    Since its inception in 1966, the North American Breeding Bird 
Survey (BBS) is the primary data source for estimating population 
trends of more than 400 species of birds breeding in North America 
(Droege 1990, p. 1). More than 4,000 BBS survey routes are distributed 
along secondary roads across the United States and southern Canada in a 
stratified random design. Each year, volunteer observers count birds 
along these routes, following standardized protocols. Surveys are 
conducted at approximately the same time each year, which is typically 
during the first half of June in most locations. Each survey route 
consists of 50 stops spaced 0.8 km (0.5 mi) apart. Observers count all 
the birds seen and heard within 0.4 km (0.25 mi) of each stop location 
during a three-minute period (Droege 1990, p. 1). The sum of the counts 
for each species over the 50 stops is used as an index of relative 
abundance for that route (Link and Sauer 2002, pp 2833).
    Statistical analyses are performed on these index values across 
routes to estimate population trends for particular species or groups 
of species. Two statistical analysis techniques are currently employed 
by analysts working with the BBS data: The route-regression method 
(Geissler and Sauer 1990, pp. 54-56) and the hierarchical model method 
(Link and Sauer 2002, pp. 2,833-2,836). The hierarchical model method 
is the more recently developed method, and BBS analysts are in 
transition from using the route-regression method to using primarily 
the hierarchical model method, which is a less subjective and more 
efficient method for estimating trend (Link and Sauer 2002, p. 2,837). 
The presentation of BBS data in the 2000 petition (Ruley 2000) used the 
route-regression method. Throughout this finding we discuss BBS data 
using the newer hierarchical model method. As a result, the figures 
used herein to describe BBS population trends differ from those used in 
the petition. Statistical analyses can be conducted across different 
time frames and spatial scales (for example, States, bird conservation 
regions, range-wide).
    It is important to recognize that the BBS was designed to estimate 
trends (changes in population) and not actual abundance (population 
size) of birds. Much of the criticism that has been leveled at the 
BBS--including doubts expressed about the BBS in the Service's positive 
90-day finding on the petition to list the cerulean warbler--stems from 
confusion about the survey's objective and the protocols required to 
meet that objective. The following discussion addresses four aspects of 
the BBS that contribute to this confusion and why these issues do not 
detract from the usefulness of BBS for tracking bird population trends.
    (1) The point count survey methodology of the BBS does not result 
in a complete count of the birds present. The efficiency with which 
birds are counted varies between observers and within observers over 
time and space. In addition, a 3-minute count is not long enough to 
detect all birds present in a given location due to temporal 
variability (both daily and seasonally) in detectability of different 
species. However, the BBS methodology does provide an index of relative 
abundance of birds along the survey routes. This index can be scaled to 
different levels of abundance using different analysis methods and 
provides an appropriate means for assessing population change along the 
routes. An index of relative abundance is suitable for tracking changes 
in the size of the entire population if the ratio between the number of 
birds detected in the surveys and number of birds actually present 
across the landscape remains fairly constant and without any 
directional bias across years (Bart et al. 1998, pp. 212-214).
    The statistical analyses of BBS data help to address some of the 
limitations pertaining to observer efficiency by incorporating 
variables that account for observer effects into the analyses. Such 
effects as differences in counts between observers in different years 
on the same route or the differences between an observer's first count 
and counts in subsequent years on the same route (the novice effect) 
are accounted for in the statistical analysis of the survey data (Sauer 
et al. 1994, pp. 59-60; Link and Sauer 2002, p. 2,834).
    Another factor contributing to incomplete counts of all the birds 
present is that most detections of forest-associated songbirds are 
largely through observers hearing the songs of males. Females of most 
forest songbirds do not sing and, therefore, are more difficult to 
detect during the breeding season. Thus, females of these species are 
greatly undersampled by the BBS. Again, this limitation is not relevant 
to the detection of population trends as long as trends in the male 
portion of the population are representative of trends in the entire 
population. For most small songbirds, such as the cerulean warbler, 
there is no substantial data indicating either a highly skewed sex 
ratio or a large difference in survival rates between the sexes such 
that trend data might be biased.
    (2) BBS surveys are conducted along roadsides and might not 
accurately reflect habitats across entire landscapes. The proportion of 
different habitat types could be different across landscapes compared 
with what is sampled by BBS routes. However, this limitation, in and of 
itself, does not render the BBS ineffective in estimating trends of 
forest birds unless there is a consistent bias in the rate of change of 
habitats bordering roads compared to change of habitats away from 
roadsides. The fact that birds that avoid habitat edges might not be as 
abundant near roads as away from roads also does not influence trend 
estimates, except perhaps to reduce overall sample size for such 
species and require more years of data or more detections to achieve 
appropriate levels of statistical significance.
    Experimental studies comparing roadside with off-road counts or 
modeling efforts to assess relative amounts of different habitats in 
the areas immediately surrounding BBS survey routes and areas away from 
routes are necessary to address the issue of roadside habitat bias for 
the BBS. Two published studies have evaluated the bias associated with 
roadsides in the eastern United States. These studies were conducted in 
Ohio and Maryland. They both concluded that, although BBS routes under-
sampled forest habitats in the regions evaluated (areas adjacent to BBS 
routes tended to have proportionately less forest cover than did the 
region as a whole), they did not find a bias in the change in habitats 
over time along BBS roadside routes compared with the larger landscapes 
surrounding those routes (Bart et al. 1995, p. 760; Keller and Scallan 
1999, pp. 53-55). These studies suggest that the roadside nature of the 
BBS does not create a substantial bias in the BBS data pertaining to 
habitat changes that are likely to influence bird population trends. In 
contrast with this apparent lack of bias in trend estimates, the 
indication from these studies that BBS routes might under-sample forest

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habitats in the East could have implications for the population size 
estimates based on the Partners in Flight method (discussed below). 
However, an unpublished study from West Virginia (Weakland et al. 2003, 
p. 8) found no significant difference between the abundance estimates 
of cerulean warblers from off-road counts and from BBS routes. The 
study found a tendency for the off-road counts to be higher than counts 
on BBS routes, but the difference was not significant. The study 
concluded that, for cerulean warblers, data collected on BBS routes in 
West Virginia are comparable to data collected from off-road locations 
(Weakland et al. 2003, p. 8).
    In the positive 90-day finding on the petition to list the cerulean 
warbler, the Service expressed doubt on the ability of BBS data to 
reliably determine bird population trends of mature forest-associated 
species, such as the cerulean warbler. Reasons for this doubt were 
primarily associated with concerns about a possible roadside bias and 
concerns about lack of uniform coverage of BBS routes across the range 
of the cerulean warbler. To date, the published evidence on the topic 
of the roadside bias suggests that the roadside nature of the BBS does 
not significantly bias its ability to accurately track population 
trends of mature forest species, such as cerulean warblers (Bart et al. 
1995, p. 760; Keller and Scallan 1999, pp. 53-55). Furthermore, the 
more recently implemented hierarchical model method for analyzing BBS 
data estimates trends more efficiently (resulting in smaller confidence 
intervals around the trend estimate) based on the available data (Link 
and Sauer 2002, p. 2837), reducing concerns about lack of uniformity in 
coverage of BBS routes, particularly at the rangewide scale.
    It is also worth noting that efforts to compare population trends 
calculated from BBS data with independent data sources have 
corroborated the trends indicated by the BBS for a variety of species, 
including independent trends based on the Christmas Bird Count, 
Mourning Dove Survey, raptor migration counts, and checklist programs 
(Droege 1990, p. 3). In addition, many peer-reviewed publications have 
been completed using BBS data (for example, Robbins et al. 1989b, Sauer 
et al. 1994, Link and Sauer 1997, Link and Sauer 1998, Royale et al. 
2002, Sauer and Link 2002), indicating the overall robustness and 
scientific credibility of the BBS and its utility for monitoring bird 
population trends.
    (3) A published analysis of BBS data using the hierarchical model 
method indicates that at the range-wide level, cerulean warblers have 
declined at an average rate of 3.04 percent per year during the period 
of 1966 to 2000, with the 95 percent credible interval (confidence 
interval for hierarchical method; C.I.) for the trend estimate being -
4.02 to -2.07 (Link and Sauer 2002, p. 2837). A more recent, but 
unpublished, analysis of the BBS data for the years 1966 to 2005 using 
the hierarchical model method indicates a similar result: cerulean 
warbler trend was -3.2 percent per year (95 percent C.I.: -4.2 to -2.0) 
for this 40-year period (USFWS 2006, Appendix 5, slide 21 of J. Sauer's 
PowerPoint presentation). This recent estimate was based on data from 
243 BBS routes on which cerulean warblers were detected at least once 
during that 40-year period. The rangewide relative abundance reported 
from this recent analysis was 0.25 birds per route, which is relatively 
low (less than 1 bird per route), and warrants some caution when 
considering the BBS results for this species, because a positive bias 
in the trend might occur with low counts, and because the variances are 
imprecise (Sauer et al. 2005b). Within the core of the species' range 
in the Appalachian Mountains (Bird Conservation Region 28), which 
currently supports an estimated 80 percent of the breeding population 
(as calculated using the methods described by Rosenberg and Blancher 
2005), the relative abundance from the recent analysis was 1.03 birds 
per route and the 40-year trend was -3.1 percent per year (95 percent 
C.I.: -4.4 to -1.7; USFWS 2006, Appendix 5, slides 17-19 from J. 
Sauer's presentation).
    Analysis of the rangewide trend over the last 10 years (1996 to 
2005) compared with the previous 30 years (1966 to 1995) indicated no 
significant change in the trend between those two periods (estimated 
change in trend = -0.5 percent, 95 percent confidence interval = -3.8, 
+3.4). The trend estimate for cerulean warblers over the first 30 years 
of the BBS was -3.0 percent per year (C.I.: -4.3, -1.8) and the 
estimate for the past ten years was -3.6 percent per year (C.I.: -6.3, 
-0.1). Because 10 years is a smaller sample size than 30 years, the 
trend estimate based on the last 10 years is less precise than the 
estimate from the previous 30 years, so that the 10-year credible 
interval completely overlaps the 30-year credible interval. Thus, the 
available data suggest that the trend for cerulean warblers has not 
changed during the more recent period and the population continues to 
decline by about 3 percent per year, including within the Appalachian 
core region (Sauer 2006).
    (4) Partners in Flight produced estimates of global population size 
for North American land birds (Rich et al. 2004, pp. 69-77) based on a 
method developed by Rosenberg and Blancher (2005, pp. 58-61). The 
estimate of the cerulean warbler population was 560,000 individuals 
based on an average of counts made on BBS routes during the period of 
1990 to 1999; it can be thought of as an estimate for the year 1995 
(the mid-point of the time period). Partners in Flight rated the 
relative accuracy of their population estimates based on known sources 
of variation and limitations of the methodology pertaining to each 
species. Statistically derived confidence limits could not be provided 
because the variance has not been measured for some of the parameters 
and assumptions used in the method. Partners in Flight rated the 
accuracy of the population estimate for cerulean warblers as 
``moderate,'' suggesting that they felt the estimate was likely to be 
within the correct order of magnitude (100,000's of birds rather than 
millions or 10,000's of birds) and could be within 50 percent of the 
true number (for example, 280,000 to 840,000).
    The Partners in Flight method uses BBS relative abundance data 
along with several assumptions and correction factors to calculate the 
estimated population size for species covered by the BBS (Rosenberg and 
Blancher 2005, pp. 58-61). The method is based on the idea that, at 
each stop on a BBS route, an observer is recording birds within 400m 
(1,300 ft ) of that stop location (per BBS survey protocol). Thus, the 
observer is effectively sampling an area equal to a circle with a 400m 
(1,300 ft) radius. Over the 50 stops of a BBS route, this sums to an 
effective sampling area of 25.1 km\2\ (9.7 mi\2\). After making some 
assumptions regarding BBS routes adequately representing habitats 
across large landscapes and assumptions about the detectability of 
birds, the average number of birds counted on BBS routes within a 
particular region can be extrapolated across that region to calculate 
an estimated population size.
    The following paragraphs present a list of the primary assumptions 
of the Partners in Flight method and discussion of the effects 
violations of these assumptions are likely to have on calculations of 
cerulean warbler population estimates.
    (a) BBS routes are distributed randomly across regional strata. The 
BBS methodology prescribes random distribution of survey routes within

[[Page 70722]]

sampling strata, and the assumption that BBS routes are randomly 
distributed has not been questioned. However, the intensity of route 
allocation within particular strata and the topographic location of 
routes are two factors that could lead to biased population estimates. 
For example, if BBS routes in the Appalachian Mountains tend to be 
along roads that follow creek bottoms, and if cerulean warblers tend to 
be more abundant on ridge tops, as indicated in Weakland and Wood 
(2005, pp. 503-504), Wood et al. (2006, pp. 160-161), and Buehler et 
al. (in press, p. 9), then the BBS counts could be biased by 
undersampling the topographic locations where these birds are likely to 
be most abundant. Both the route allocation and topographic location 
biases could lead to an underestimate of total cerulean warbler 
population size.
    (b) BBS routes sample habitats in proportion to their relative 
amounts within the regional strata. The possibility of a habitat bias 
from the roadside nature of BBS routes contributes to uncertainty about 
the accuracy of population estimates derived from the Partners in 
Flight method. As discussed above in relation to population trend 
estimation, the two studies that have been conducted in the eastern 
United States have shown that BBS routes in Ohio and Maryland 
undersample forest habitats compared to the surrounding landscape (Bart 
et al. 1995, pp. 759-761; Keller and Scallan 1999, pp. 53-55). If a 
similar bias toward underrepresenting forest habitat exists throughout 
much of the cerulean warbler's range, then such a bias would result in 
an underestimation of the total population size when using the Partners 
in Flight method. Various efforts are underway to evaluate the habitat 
bias of BBS routes across much of the United States, but results are 
not available yet.
    (c) Detectability of different bird species is a function of their 
distance from the observer and time of day, and all species have a 
fixed, average maximum detection distance. Correction factors for 
detection distance and time of day were incorporated into the 
estimation method to address this assumption. For the detection 
distance, species were assigned to one of five categories corresponding 
to different average maximum distances at which these birds were likely 
to be detected based on habitat type, song quality, and likelihood of 
being detected in some way other than by song (for example, hawks 
soaring in the distance): 80m (260 ft), 125m (400 ft), 200m (650 ft), 
400m (1,300 ft), and 800m (2,600 ft). These different detection 
distances result in different effective sampling areas for BBS routes. 
Cerulean warblers were assigned a detection distance of 125m (400 ft), 
which is the assumed average maximum distance at which an observer will 
be able to detect a singing bird. This assumption has not been tested, 
and some experts believe that this detection distance might be an 
overestimate of the distance at which a singing cerulean warbler can 
always be heard; it is unlikely to be an under-estimate (USFWS 2006, 
Appendix 4, Day 2--pp. 1-2). If the real maximum detection distance for 
this species is less than 125m (400 ft), it would result in a larger 
population estimate based on the Partners in Flight method. For 
example, using a detection distance of 100m (325 ft) would result in a 
population estimate that is approximately 60 percent higher than the 
estimate using a 125m (400 ft) detection distance. The large influence 
of relatively small changes in detection distance on the resulting 
population estimate indicates that detection distance is a critical 
parameter in the population estimation methodology and contributes a 
large amount of uncertainty pertaining to the population estimate for a 
particular species when the accuracy of this parameter is unknown.
    To correct for detection issues associated with time of day, 
Rosenberg and Blancher (2005, pp. 59-61) developed distribution curves 
of the detections for each species over the 50 stops of BBS routes. 
Based on these curves, peak detection probabilities were determined for 
each species and then a ratio of the peak detections to average 
detections was calculated. This ratio is used to adjust the average 
numbers of birds detected per route to peak numbers per route, 
reflecting numbers that would be expected if the peak detection 
probability lasted throughout the morning hours when BBS routes are 
surveyed. The time of day correction factor calculated for cerulean 
warbler is 1.35 (Rosenberg and Blancher 2005, p. 63--Table 2). The 
methods for deriving this correction factor are empirically based, and 
there is little reason to believe that it is biased or otherwise 
inappropriate for cerulean warblers.
    One potential correction factor that was not incorporated into the 
Rosenberg and Blancher (2005) method and that could influence 
population estimates for cerulean warblers is a correction for 
detectability associated with the season. The song rate of most 
cerulean warbler males declines once they become mated and as the 
breeding season progresses (USFWS 2006, Appendix 4, Day 2--p. 2). The 
breeding season typically begins between mid-April and early May 
throughout much of the breeding range. Most BBS routes are run during 
the first half of June, and overall song rate of mated males is likely 
to be lower at that time than earlier in the breeding season. Such a 
time of season effect could contribute to an under-estimate of the 
total cerulean warbler population size.
    (d) Individuals detected during a count represent one member of a 
pair. A pair correction factor of two times the initial estimate was 
also incorporated into the method to address Assumption D. Most 
individuals in breeding populations are mated during the time of the 
BBS survey, but it is usually only one member of each pair that is 
detected (for example, a singing male). Rosenberg and Blancher (2005, 
p. 61) acknowledge that the appropriate pair correction factor for all 
species is somewhere between one and two, because not all individuals 
in a breeding population are mated. However, this correction factor has 
not been empirically established for any species yet. Field studies 
indicate that not all male cerulean warblers attract mates during the 
breeding season, although some males of this species are also known to 
be bigamous (USFWS 2006, Appendix 4, Day 2--p. 2). The proportion of 
unmated and bigamous males across the species range is unknown. The 
most appropriate pair correction factor for cerulean warblers might be 
a number less than two, but insufficient data currently exist to 
estimate what this number should be for the entire population. A pair 
correction factor less than two would result in a smaller population 
estimate, while a pair correction factor greater than two would result 
in a larger population estimate.

Status of the Cerulean Warbler Population

    We used a stepwise approach to evaluate what single factor or 
combination of factors may affect the cerulean warbler's population 
trend in order to evaluate whether the species warrants listing as 
threatened or endangered under the Endangered Species Act. First, we 
used all available information, including that contained within the 
petition, scientific literature, and expert opinion (USFWS 2006) to 
identify potential factors that might explain the historical and 
projected population trends (see previous section ``Population Size and 
Trend''). Next, we gathered information to assess whether the 
likelihood of occurrence or magnitude of effect of the factors were 
likely to result in population-level effects. We used the qualitative 
judgments of independent experts (USFWS 2006) to assess these potential

[[Page 70723]]

causal factors where quantitative data are unavailable. Then, we 
synthesized the information on the past and future factors with 
estimates of historical (Link and Sauer 2002, p. 2837, Sauer 2006) and 
projected (Thogmartin 2006) cerulean warbler population trends to 
estimate to what degree potential factors might influence the species' 
risk of extinction. Finally, we compared the results of our analysis to 
the five factors listed in the Act to ensure thorough consideration of 
potential threats, and, in light of the Act's five-factor analysis, we 
evaluated whether the species' current or projected status met the 
definitions of threatened and endangered.

Summary of Factors Affecting the Species

    Section 4 of the Act (16 U.S.C. 1533) and our implementing 
regulations at 50 CFR part 424 set forth the procedures for adding 
species to the Federal endangered and threatened species list. 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), as 
follows: (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 making this finding, information regarding the 
status of, and threats to, the cerulean warbler in relation to the five 
factors is discussed below.
    In developing our 12-month finding for the cerulean warbler, we 
considered all scientific and commercial information on the status of 
the species that we received during the comment period following our 
90-day finding. We also searched the scientific literature for relevant 
data and consulted experts on the cerulean warbler and threats to its 
habitat to ensure that this finding is based on the best scientific and 
commercial data available.
    As noted earlier, we considered the population trend estimate of -
3.2 percent per year (CI = -4.2 to -2.0), which is based on Breeding 
Bird Survey data (Link and Sauer 2002, p. 2837; Sauer unpublished data 
2006), to be the best available representation of the species 
population status. This trend estimate comprises all of the factors 
causing population change during the 40-year period of Breeding Bird 
Survey data collection. In other words, all the factors affecting 
cerulean warbler demographics have combined over the past 40 years to 
produce an annual average decline of 3.2 percent per year, with 90 
percent certainty that the true decline is between 4.2 and 2.0 percent 
per year (Link and Sauer 2002, p. 2837; Sauer unpublished data 2006). 
The information available suggests that the factors described in this 
section will continue affecting cerulean warbler habitats and 
demography in a similar manner, resulting in a continuing population 
decline of approximately 2 to 4 percent per year.
    We describe the potential contributing factors to the species' 
approximately 3 percent annual decline in the following description of 
the five listing factors (iterated above).

A. The Present or Threatened Destruction, Modification, or Curtailment 
of Its Habitat or Range

    After consideration of all available information, the Service has 
determined that four biological mechanisms operating throughout the 
species' annual range are likely to be primary contributors to the 
species' declining population trend. Each of these mechanisms is 
related to changes in habitat in North America, South America, and 
along the species' migration routes. These mechanisms are:
    1. Reduction in available nesting sites and suitable breeding 
territory characteristics because of loss or degradation of habitat,
    2. Reduction in foraging success resulting from decreased prey 
abundance, primarily on the wintering ground in South America,
    3. Increased predation throughout the species' annual range and 
nest parasitism of cerulean warblers in the breeding grounds, resulting 
from habitat fragmentation, and
    4. Loss of migration habitat.
    Each of these four mechanisms results, either directly or 
indirectly, from the reductions in quality and quantity of cerulean 
warbler habitat (Factor A of the Act) and therefore, all will be 
discussed under Factor A.
    1. Reduction in available nesting sites and suitable breeding 
territory characteristics because of loss or degradation of habitat:
    Although we do not have a rangewide numerical relationship between 
habitat loss and population change, we do know that there is a positive 
relationship between cerulean warbler nest presence and mature and old-
growth hardwood forests with large trees, small gaps, and vertical 
diversity in vegetation layers (Hamel 2000b, pp. 12-18; Weakland and 
Wood 2002, p. 13). Therefore, we can conclude that degradation or 
removal of suitable mature and old-growth hardwood forestland will 
result in reductions in nesting opportunities, and that accumulation of 
habitat losses is likely to result in declines in cerulean warblers.
    We do not know what happens to individual birds when breeding 
habitat is removed. Displacement of adults and mortality of nestlings 
is likely if removal of nesting stands occurs during the breeding 
season. Nestling or post-fledging mortality may also occur if habitat 
within nesting territories is eliminated or quality is reduced below an 
unknown threshold level. Results of recent studies suggest that 
cerulean warblers are capable of interannual movement (Veit et al. 
2005, pp. 165-166; USFWS 2006, Appendix 5f, slide 17 of Jones 
PowerPoint); therefore, breeding habitat loss during the non-breeding 
season is likely to result in relocation of adults that return during 
the subsequent breeding season. However, the degree to which 
reproductive success or survival of displaced individuals is affected 
is likely dependent upon several variables, including whether the 
displaced birds relocate into already occupied or unoccupied, or 
whether remaining habitat is optimal or suboptimal. We do not have 
information to assess the degree and type of impact of breeding habitat 
of site-specific habitat loss, unless known occupied nests are removed.
    Degradation of habitat quality can occur at several scales, and the 
resulting effect on cerulean warblers is likely to be context-
dependent. Loss of a single dominant tree in a stand possessing 
numerous other dominant trees may have little or no effect on the 
reproductive success of breeding cerulean warblers, whereas loss of a 
single dominant tree in a stand having few other large trees may render 
a formerly suitable site unsuitable for nesting birds. Context is 
probably similarly important at larger scales. Reduction in patch size 
and introduction of hard edges may result in greater local population 
declines and habitat unsuitability where a forest stand is surrounded 
by an already fragmented landscape as opposed to largely intact forest. 
Thus, habitat content factors that operate at local scales (to include 
nest trees, prey base, etc.) and habitat context factors that operate 
at larger scales (to include things like habitat patch size, degree of 
landscape fragmentation, etc.) are both important determinants of 
overall habitat quality for breeding cerulean warblers.

[[Page 70724]]

    The amount, distribution, and quality of habitat for breeding 
cerulean warblers has been altered dramatically since European 
settlement in the early 1600s. An estimate of total forestland in 1630 
in 19 States in which cerulean warblers occur today and for which there 
was analyzed BBS data (Sauer 2006) was 133,000,000 ha (328,695,000 ac) 
(Smith et al. 2004, p. 33, citing Kellogg 1909). Today, the estimate of 
forest cover in those same States is 73,600,000 ha (181,850,000 ac) 
(Smith et al. 2004, p. 33), a total reduction of approximately 45 
percent. The most dramatic change occurred between the early 1600s and 
1900, when approximately 51 percent of forestland was converted to 
agricultural and other uses (Smith et al. 2004, p. 33). Since 1900, 
approximately 8,500,000 ha (21,000,000 ac) have reverted from primarily 
agricultural uses to forestland. Approximately 52 percent of today's 
hardwood forest within the eastern United States is in mature sawtimber 
(Smith et al. 2004, p. 64); some of this area is northern hardwood 
forest and outside the range of the cerulean warbler.
    The cerulean warbler appears capable of using previously unoccupied 
stands that have matured to develop necessary habitat characteristics. 
Evidence of this capacity comes from New Jersey, New York, and parts of 
New England, where the species has recently expanded its range (Hamel 
1992, pp. 385-400; Robbins et al. 1992, p. 551). Population information 
indicates that this expansion occurred during the later part of the 
1900s, although experts suggest that the expansion does not appear to 
be continuing today (USFWS 2006, Appendix 4, Part II, p. 5). We do not 
know the distribution of cerulean warblers prior to 1966; therefore, we 
do not know whether this expansion is a reoccupation of restored forest 
or true expansion into an area not previously occupied.
    Despite this recent, gradual increase in the total amount of 
forestland, cerulean warbler populations have declined since 1966, 
according to Breeding Bird Survey data. Several hypotheses could 
explain this phenomenon: (1) The amount of forest stands with diverse 
structure continues to decline even though total forestland acres 
increases; (2) local reductions in nesting opportunities in core 
breeding areas are having disproportionate effects at the population 
level; or (3) factors occurring elsewhere in the species annual range 
or not related to nesting opportunities are causing the decline. We 
will discuss each of the first two of these factors in the following 
text, and the third factor in subsequent sections.
    Rangewide data are not available to quantitatively assess the 
amount of or change in habitat with desired characteristics for 
breeding birds. Nevertheless, several pieces of information are 
important for consideration. It takes hundreds of years for hardwood 
forests to naturally achieve complex structure of mature and old-growth 
forests (Hamel 2000, p. 12 citing Widman), which are characteristic of 
stands selected by cerulean warblers for breeding. Much of the 
reversion of agricultural lands to forestland has occurred since the 
early 1900s; therefore, much of the new acreage in forestland remains 
in relatively younger stands that have yet to achieve desired 
structural complexity. We note, however, that stand heterogeneity is 
likely a more important predictor of habitat quality than simply 
looking at stand age, because natural and anthropogenic disturbances 
can create desired stand complexity. Forest management practices, such 
as high-grading, may also affect habitat quality if the largest trees 
in the stand are removed, reducing structural complexity. Fire 
suppression, species-specific tree diseases, and locally or regionally 
high deer densities may also reduce the complexity of forest structure.
    Effects in a relatively small portion of the species' range, 
compared to the species' entire breeding range, could contribute 
disproportionately to the population decline. This has likely happened 
in the past and may happen in the future. Historically, cerulean 
warblers were probably numerous in the bottomland hardwood forests of 
the Mississippi Alluvial Valley. Today, approximately 80 percent of 
forest in this area has been converted to nonforest uses (Brown et al. 
2000, p. 6). Nesting cerulean warblers currently occur only in 
scattered locations within this region. It is important to note that 
most of this loss occurred before the Breeding Bird Survey began in 
1966. Currently, large-scale habitat loss is occurring in the core of 
the species' range, Kentucky and West Virginia, where mountaintop coal 
mining and valley fill operations through 2012 are expected to remove 
567,000 ha (1.4 million ac) of suitable forest habitat (USEPA 2005). 
The total cumulative forest loss from these activities will likely 
eliminate breeding habitat for 10 to 20 percent of the total cerulean 
warbler population currently occurring within that core area. The loss 
of breeding opportunities for birds in this area may have a 
disproportionate effect on the species' total population size.
    The USDA Forest Service has projected forest change to the year 
2050 (Alig and Butler 2004). These projections are based on prior 
trends in forest change, expected market conditions, and no change in 
forest management related policies. Under these conditions, the Forest 
Service expects a slight decline in hardwood forest area. Hardwoods 
will continue to dominate the southeastern United States; however 
hardwood forest area is expected to decline by up to 18 percent by 2050 
(Alig and Butler 2004, pp. 32-33). Maple-beech-birch and oak-hickory 
forests are estimated to decrease by 6 percent and 15 percent, 
respectively (Alig and Butler 2004 p. 18). We note that small portions 
of the hardwood forest area contained within these estimates are 
outside the range of the cerulean warbler; refer to Alig and Butler 
(2004, p. 2) for a map of the forest survey area. We stress that 
changes in acreage or percent of forest landscape in hardwoods are only 
one determinant, and the actual composition and structure of hardwoods 
forests in future landscapes may be equally or more important.
    In summary, a variety of factors has affected the quantity and 
quality of mature and old-growth hardwood forests within the range of 
the cerulean warbler. Overall, habitat loss beginning in the 1600s 
likely precipitated a decline in cerulean warblers; however, the 
conversion of forests stabilized with about 50 percent of forestland 
remaining in the early 1900s. Rangewide cerulean warbler population 
information did not become available until the 1960s; therefore, we do 
not know how the pre-1900s cerulean warbler population size changed as 
a result of this dramatic habitat loss, nor how it may have responded 
to post-1900 forest changes. Beginning in the 1900s, re-growth of 
forests previously converted to agriculture has added potential 
breeding habitat that may be reoccupied when stands achieve the 
characteristics selected for by cerulean warblers, as evidenced today 
in the Northeastern United States.
    2. Reduction in foraging success resulting from decreased prey 
abundance, primarily on the wintering ground in South America:
    Cerulean warblers feed exclusively on insects in North America, and 
on insects and nectar in South America. Availability of these resources 
is critical to an individual bird's survival. Insufficient fat storage 
before spring migration could increase an individual's risk of 
mortality and decrease reproductive success upon return to the breeding 
grounds. Insufficient fat

[[Page 70725]]

storage before fall migration could leave an individual at risk of 
mortality, especially if the migration route is over water where 
foraging opportunities are limited, as is currently hypothesized.
    Winter range--Abundance of food resources in South America has 
likely declined because of the degradation and removal of tropical 
forests. Removal of overstory trees, as forests are cleared and shade-
grown coffee plantations are converted to sun coffee plantations, is 
expected to result in losses of arthropods that are specialized for the 
canopy layers. For example, in Costa Rica, Perfecto (1996, p. 602) 
reported an average of 72 percent of the ants in a tropical forest tree 
canopy to be canopy specialists. However, that we do not know that 
cerulean warblers prey on ants. In a Costa Rican study, Perfecto et al. 
(1996, p. 602) reported similar arthropod diversity in overstory trees 
within shade-grown coffee plantations as within a native forest canopy. 
We do not have figures for arthropod diversity or abundance in the 
Northern Andes, but we expect that conditions may be similar. We do not 
have quantitative information on the differences in nectar resources 
between tropical forest and developed lands.
    Moreno et al. (2006, p. 3) used a climatic and geospatial model to 
predict the potential maximum occurrence of cerulean warbler wintering 
habitat in the narrow elevation zone (500 to 1,500 m (1,650 to 5,000 
ft)) in the Northern Andes and estimated a nearly 60 percent current 
reduction from maximum levels. The remaining habitat is tropical forest 
and shade-coffee plantations. Some field biologists believe that the 
model overestimates habitat availability, and they estimate that less 
than 10 percent remains (Moreno et al. 2006 unpublished report, pp. 3, 
    Most of the loss of tropical forests in the Northern Andes occurred 
within the latter half of the 1900s. Approximately 15 percent of the 
species' modeled potential habitat (Moreno et al. 2006 unpublished 
report, p. 5) is managed under protective status. The effectiveness of 
this protective status for conserving cerulean warblers is uncertain 
because none of the documented cerulean warbler winter occurrences are 
within protected areas (Moreno et al. 2006 unpublished report, p. 5). 
The rate of loss of the remaining tropical forest is likely to be 
decreasing because remnant forests are in steep and inaccessible areas; 
however, removal of portions of the remaining tropical forests 
    We know that cerulean warblers occupy shade-coffee plantations 
during the non-breeding season, but we do not know whether shade-coffee 
plantations are optimal or sub-optimal habitat because data are not 
available to compare body condition of cerulean warbler on shade-coffee 
plantations with birds occupying tropical forests. In other words, 
presence does not necessarily equate to suitability of these habitats. 
The amount of habitat supplied by shade-coffee plantations is 
diminishing, as some of these plantations are converted to sun-coffee 
plantations that lack the overstory required by wintering cerulean 
warblers (Moreno et al. 2006 unpublished report, p. 2). Cerulean 
warblers are not known, and are highly unlikely, to occur in sun-coffee 
plantations due to the plainly inadequate structure of such vegetation.
    In summary, the population-level effects of habitat loss and 
degradation on forage abundance and foraging success have not been 
quantified. It is reasonable to conclude, however, that a greater than 
60 percent decline of wintering habitat in South America has 
contributed to the approximately 3 percent annual population decline of 
cerulean warblers through reduced forage availability and increased 
competition for remaining food resources.
    Breeding and Post-Fledging Range--Under pre-European settlement 
conditions on the breeding grounds, the hardwood forests of the eastern 
United States were a mosaic of different seral stages (Williams 1989, 
pp. 22-49). Although the forests were predominately mature and old 
growth, patches of younger seral-stage forests occurred within small 
gaps (Lorimer 1989, pp. 565-566). Today, cerulean warblers occur in 
greater relative abundance within landscapes with similar mosaic 
characteristics. Information suggests that cerulean warblers select 
nests sites in stands where canopies are interrupted by small gaps and 
canopy closure is between 65 percent and 85 percent (Hamel 2000, p. 
16). Nests are found in areas with large diameter trees and stands with 
complex canopies, but small patches of seedling-sapling aged trees 
within the mature forest mosaic may provide important habitat for post-
fledging first-year birds.
    Today's mature forest characteristics may not mimic the mosaic 
conditions of original hardwood forest because of alterations in the 
disturbance regimes through fire suppression, dense populations of 
deer, and certain timber harvest methods. The effects of this change in 
forest disturbance regimes on cerulean warblers are not well studied or 
understood. It is possible, however, that the replacement of the 
natural disturbance regime--characterized by frequent, small-scale 
disturbances--with the less-frequent larger-scale disturbances (Lorimer 
1989, pp. 565-566) may not produce understory conditions that favor 
foraging success for post-fledging birds because of the lack of 
interspersed seedling-sapling patches.
    3. Increased predation throughout the species' annual range and 
nest parasitism of cerulean warblers in the breeding grounds, resulting 
from habitat fragmentation:
    Fragmentation of cerulean warbler habitat has occurred throughout 
the species' range. High rates of predation and brood parasitism often 
accompany habitat loss and fragmentation, especially in forested 
landscapes interspersed with agricultural lands and grasslands (Hoover 
and Brittingham 1993, p. 234; Brittingham and Temple 1983, pp. 31-34; 
Faaborg et al. in Martin and Finch 1995, p. 361). Several studies have 
shown low rates of nest success (less than 40 percent) for cerulean 
warblers in areas of fragmented forest within agricultural landscapes 
due to high levels of predation and the presence of nest parasitism 
(Hamel 2000a, p. 4; Roth 2004, p. 43; Varble 2006 p. 3). Direct 
measurements of adult and post fledging mortality due to habitat loss 
and fragmentation during the breeding season on cerulean warblers do 
not exist; however, this phenomenon is well documented with other 
canopy and sub-canopy nesting songbird species. It is reasonable to 
conclude that brood parasitism and predation are exacerbated by habitat 
loss and fragmentation and that this is contributing to the 
approximately 3 percent annual population decline.
    Wintering Range--Effects of habitat loss and fragmentation include 
increased risk of mortality from predation of neotropical migrant 
songbirds in the non-breeding range (Rappole et al. 1989, p. 407; Petit 
et al. in Martin and Finch 1995, pp. 179-180), especially if birds are 
forced to wander outside optimal habitat. Although no studies of 
predation on cerulean warblers in the non-breeding range have been 
conducted, it is reasonable to assume that predation-caused mortality 
of cerulean warblers is similar to that documented for other warbler 
    Approximately 60 to 90 percent of wintering habitat of cerulean 
warblers in South America has been converted to other land uses. This 
loss of habitat has resulted in a highly fragmented landscape. 
Geospatial modeling estimates that fragmentation of this habitat has 
more than doubled (Moreno et al. 2006, p. 14, unpublished report).

[[Page 70726]]

    Breeding Range--Nest parasitism and predation usually result in 
mortality of nestlings and post-fledging birds. Brown-headed cowbirds 
(Molothrus ater) lay their eggs in the nests of other species, and when 
hatched, cowbird chicks outcompete the chicks of the natural parents. 
Likely nest predators are corvids, chipmunks, squirrels, and other 
arboreal animals.
    Populations of cowbirds and avian predators are higher in highly 
fragmented forests and in areas where edges delineate sharp differences 
in land use between the forests and the adjacent stands. For example, 
cowbird abundance is greater along forest and agricultural edges than 
along edges created by different forest age classes (Rodewald and 
Yahner 2001, p. 1021) and are more common where human development 
provides new feeding sites, such as pastures. Overall, however, cowbird 
populations have declined since breeding bird surveys began in 1966 
(Robbins et al. 1992, p. 7661). We do not know whether, or the degree 
to which, reductions in cowbird populations result in less pressure on 
cerulean warblers.
    Effects of habitat loss and fragmentation on songbirds of North 
America have been relatively well studied compared with birds in South 
America; however, little specific information is available on cerulean 
warblers. In general, we know that increased fragmentation and 
decreased habitat patch size within the breeding range is likely to 
increase risk of predation and nest parasitism (Robinson et al. 1995, 
pp. 1988-1989; Donovan et al. 1995, p. 1393). Nest success was low 
(less than 25 percent) at Big Oaks National Wildlife Refuge in Indiana 
due to nest predation and nest parasitism; the breeding habitat on the 
refuge is surrounded by an agriculturally dominated landscape (Roth 
2004, p. 43; Varble 2006, p. 3).
    Studies on cerulean warblers have concluded that increased distance 
from edge was a significant positive predictor of cerulean warbler 
territory density (Bosworth 2003, p. 21; Weakland and Wood 2002, p. 
505). The reason for decreased cerulean warbler density near edges is 
not known, but may be a result of lower availability of suitable or 
optimal habitat near edges, or edge habitat avoidance, possibly as a 
result of increased predation pressure or other factors. The effects of 
fragmentation are likely to be context-dependent, where increasingly 
fragmented landscapes lead to decreased reproductive success due to 
increased predation and brood parasitism (Donovan et al. 1995, p. 
1393). Specifically, Donovan et al. (1995) found that nest failures of 
three forest-nesting, neotropical migrants (ovenbird (Seiurus 
aurocapillus), red-eyed vireo (Vireo olivaceus), and wood thrush 
(Hylocichla mustelina)), were significantly higher in fragmented 
forests than in contiguous forests.
    4. Loss of migration habitat:
    Migrating warblers that cross the Gulf of Mexico to and from 
breeding and wintering grounds depend on finding suitable patches of 
terrestrial habitat near coastlines. Such habitats are essential in 
providing food resources necessary to replenish energy and fat stores 
of enroute migrants and to provide shelter from predation and inclement 
weather events. As coastal forest habitat along the U.S. and Central 
American Gulf coasts is lost to development and conversion, compounding 
the adverse impacts of hurricanes and other natural factors, the 
vulnerability of cerulean warblers to mortality during migration has 

Conservation Actions Currently Underway

    There are several existing conservation actions and programs that 
specifically focus on the cerulean warbler and its habitat. We did not 
rely on these ongoing conservation actions in our determination that 
listing the cerulean warbler is not warranted and, therefore, we did 
not evaluate them under our 2003 Policy for Evaluation of Conservation 
Efforts When Making Listing Decisions (68 FR 15100; March 28, 2003). 
The cerulean warbler Technical Group (CWTG) is a partnership of 
biologists, managers, and scientists from the forest-products industry, 
Federal and State agencies, nongovernmental organizations, and 
academia. It was formed in 2001 to develop a broad-based, technically 
sound approach to conservation of the cerulean warbler. By seizing the 
initiative and bringing key stakeholders and technical experts 
together, the CWTG seeks to keep the focus on identifying meaningful 
and proactive conservation solutions through sound science, clear 
communication, and trust. CWTG was loosely modeled after the highly 
successful Louisiana Black Bear Conservation Committee formed in the 
early 1990s. Collaborative actions of the CWTG on behalf of the species 
are coordinated by a Steering Committee charged to spur action and 
chart future activities and directions. There are currently 72 CWTG 
participants working on the following committees: Coordination, 
conservation, monitoring, research, international, and mining. Hamel et 
al. (2004, pp. 12-14) provides a thorough discussion on the history, 
organization, and objectives of the CWTG.
    In December 2002, the CWTG met at the National Conservation 
Training Center in Shepherdstown, West Virginia, at a workshop 
sponsored by the Service and the U.S. Geological Survey. This important 
workshop was attended by 65 people from a broad category of 
disciplines, including biologists from Colombia, Ecuador, and 
Venezuela. The main purpose of the workshop was to develop a proactive, 
broad-based, and cohesive strategy for cerulean warbler conservation. 
Four working groups were established; their goals and accomplishments 
are summarized below:
    (1) The Breeding Season Research Group identified rangewide 
research priorities and designed a research experiment to test cerulean 
warbler response to commonly applied forest management practices, 
replicated at five study areas across the core of the breeding range. 
The project will provide information on cerulean warbler ecology and 
demography, and insights to key limiting factors and to management 
prescriptions that could benefit it and associated species. In 2003, 
the project was endorsed by the Northeast and Southeast working groups 
of Partners in Flight as the highest research priority for forest 
songbird conservation.
    (2) Priorities for the Breeding Season Surveys and Monitoring Group 
are to map cerulean warbler distribution more completely, improve 
regional and global estimates of population size and trend, and 
integrate inventory and monitoring efforts with predictive modeling. 
Successes include bringing together major forest-products companies in 
the mid-Appalachians in partnership with the National Council for Air 
and Stream Improvement (NCASI) and the Cornell Laboratory of 
Ornithology to evaluate cerulean warbler status on as much as 100,000 
ha (250,000 ac) of likely suitable habitat that have not previously 
been surveyed. During the nesting seasons of 2003 to 2005, the partners 
surveyed hundreds of points on private lands. The data are being used 
to test and refine predictive models, developed by University of 
Tennessee, the Service, and U.S. Geological Survey, on the spatial 
distribution, abundance, and habitat associations of cerulean warblers 
in their core breeding range.
    (3) The Breeding Season Conservation Group is developing a vision 
and goals for long-term sustainability of cerulean warblers within the 
context of integrated ecosystem conservation and to develop habitat 
conservation and management recommendations for the

[[Page 70727]]

cerulean warbler that can be incorporated into management plans for 
public and private forestlands within its range. One venue for pursuing 
these goals is the Appalachian Mountains Bird Conservation Initiative 
(under the Atlantic Coast Joint Venture), a partnership organized to 
facilitate effective proactive conservation for all birds in the 
Appalachian Mountains region with an emphasis on cerulean warblers and 
ecologically related species.
    (4) The Non-Breeding Season Group, El Grupo Cer[uacute]leo, 
promotes a multispecies approach to habitat conservation on the 
wintering grounds (including other resident at-risk species that co-
occur with cerulean warblers). This group has compiled a database of 
documented observations of cerulean warblers, assessed non-breeding 
threats and conservation coverage, identified opportunities for 
outreach and education to communicate awareness of migratory bird 
issues, and (through the U.S.D.A. Forest Service and The Nature 
Conservancy) provided funding for South American biologists to conduct 
new research on cerulean warblers in the winters of 2003-2004 through 
2005-2006. Two workshops (March 2003 and November 2005) in Ecuador with 
biologists and modelers from throughout northern South America resulted 
in GIS-based, spatially explicit models of cerulean warbler winter 
habitat. El Grupo Cer[uacute]leo recently assisted other conservation 
organizations in securing an important non-breeding habitat reserve for 
the cerulean warbler in Colombia (see more on this action in discussion 
of Important Bird Areas below).
    The cerulean warbler Technical Group is moving forward on the 
premise that the most successful conservation efforts for cerulean 
warblers will be those that bring together broad partnerships to 
achieve common goals. To that end, the CWTG Steering Committee 
conducted two separate one-day meetings with forest and coal industry 
biologists and managers in March 2006 in Charlestown, West Virginia. 
The purpose of these meetings was to begin discussions with these two 
industries on cooperative efforts to broaden cerulean warbler 
conservation management. Both meetings explored the constraints and 
potential options for cerulean warbler conservation in the Appalachians 
and establishing a foundation for a broader conservation partnership 
summit in February of 2007 that will focus on actions.
    There are several projects currently being conducted to study the 
response of cerulean warblers to targeted management efforts to restore 
the quantity and quality of its breeding habitat. As previously 
discussed in this finding, quality cerulean warbler breeding habitat 
consists of mature forests with a diverse and vertically complex canopy 
structure, including canopy gaps and associated midstory and understory 
vegetation. Biologists and land managers are manipulating (managing) 
forest areas to create the complex canopy structure required by 
cerulean warblers. If these research and management studies are 
successful, these methods could be used in many public and private 
forests to restore the cerulean warbler's breeding habitat and enhance 
its reproductive capability in a shorter period of time.
    The most comprehensive effort involving the scientific evaluation 
of managing and restoring cerulean warbler breeding habitat is the 
Cooperative Cerulean Warbler Forest Management Project, which was 
developed by the Cerulean Warbler Technical Group. Study areas include 
a national forest in eastern Kentucky, a State wildlife area in north-
central Tennessee, a State wildlife area in southeastern Ohio, a State 
wildlife area in north-central West Virginia, national forests in 
eastern West Virginia, and an area of private forest industry lands in 
the coal fields of southern West Virginia. Each study area will consist 
of four sites representing different levels of forest management 
intensity: (1) No management, (2) selective harvest with 75 percent 
residual canopy cover, (3) selective harvest with 50 percent residual 
canopy cover, and (4) even-aged harvest (clearcutting, less than 10 
percent residual canopy cover). Each site will be 20 ha (50 ac), with 
the management actions being applied on a 10 ha (25 ac) area in the 
center of each site. This configuration will allow for an undisturbed 
buffer at least 100 m (330 ft) to isolate the management activities and 
for assessing edge effects around the different levels of management 
intensity. Two years of pre-harvest monitoring (2005, 2006) and two 
years of post-harvest monitoring (2007, 2008) will occur on each site. 
The pre-harvest monitoring has been conducted and the forest management 
actions are scheduled to occur during the fall and winter of 2006-2007. 
A similar forest management-cerulean warbler study is being conducted 
on the Chattahoochee National Forest in northern Georgia.
    In 2005, Fundacion Aves (the ProAves Foundation of Colombia) and 
the American Bird Conservancy were successful in securing a 1,250-ha 
(500-acre) reserve of Andean subtropical forest in the Rio Chucur basin 
of Santander, Colombia (within the Serrania de los Yariguies Important 
Bird Area) to protect wintering habitat for the cerulean warbler. The 
area, one of the last natural forest fragments in the region, contains 
high populations of wintering cerulean warblers. This is the first 
South American reserve designed to protect a bird species that nests 
solely in the United States and Canada. The reserve is also a focal 
point for a continuing regional conservation campaign for the cerulean 
warbler. Another key area for wintering cerulean warblers--southwestern 
Antioquia, Colombia--has been targeted for further conservation 

Factor A Summary

    We believe that the combined effects of habitat loss have 
accumulated to produce the 40-year average annual decline of 3.2 
percent per year, with 90 percent certainty that the true decline is 
between 4.2 and 2.0 percent per year. As stated earlier, we do not have 
information to suggest that the population trend will shift outside the 
credible interval (Link and Sauer 2002, p. 2837; Sauer 2006) in the 
future, and we, therefore, assume that the factors described above will 
continue to support the declining population trend between -4.2 and -
2.0 per year. Notwithstanding this assumption, the Service does not 
find that the cerulean warbler is likely to become a threatened or 
endangered species within the foreseeable future throughout all or a 
significant portion of its range.

B. Overutilization for Commercial, Recreational, Scientific, or 
Educational Purposes

    We are not aware of any commercial, recreational, or educational 
uses that result in adverse impacts to the species or to individuals, 
nor do we envision any such threats developing in the foreseeable 
    There is a potential for adverse impacts resulting from scientific 
purposes, but data indicate that such impacts are negligible. All 
scientific activities in the United States that involve taking (for 
example, pursuing, capturing, hunting, shooting, wounding) cerulean 
warblers, their nests, or their eggs require a permit issued by the 
Service under authority of the Migratory Bird Treaty Act. In the United 
States, 13 cerulean warblers were taken under scientific research 
permits from the beginning of 2000 to the present, an average of fewer 
than 3 birds per year. Currently there are four valid and active 
scientific collection permits that allow the potential lethal take of 
up to 20 additional cerulean warblers through

[[Page 70728]]

March 31, 2008 (Andrea Kirk, Migratory Birds Permit Chief, USFWS Region 
3, 2006, in litt.). This level of mortality is deemed to be of 
negligible impact on a species whose population is most likely in the 
hundreds of thousands of individuals.
    Other research projects that include handling cerulean warblers, 
such as capturing and handling individuals for banding or applying 
other markings, may accidentally result in serious injury or death to a 
small percentage of the captured birds. Permits for these activities 
are issued by the Bird Banding Laboratory (BBL) of the Biological 
Resources Division of the U.S. Geological Survey. Data from the BBL 
show that only 1,879 cerulean warblers were banded during the 50-year 
period from 1955 to 2004 (BBL data, accessed on September 8, 2006, at 
http://www.pwrc.usgs.gov/BBL/homepage/listalph.htm). The number of 

cerulean warblers banded during this period is much lower than almost 
all other warbler species banded during this 50-year period (only four 
other warbler species had a lower number of bandings). For instance, 
3,469 golden-cheeked warblers and 3,236 Kirtland's warblers (both 
endangered) were banded during this period and 26,919 blackburnian 
warblers. Compared to banding activities involving other warbler 
species, this is a very low incidence of banding and handling, 
indicates that there has been little intentional or incidental banding 
activity with this species. The behavior of cerulean warblers generally 
keeps them high in the forest canopy, leading to a low frequency of 
capture in the mist nets used by bird banders. Thus, we conclude that 
there are few (if any) adverse populations impacts resulting from 
banding or marking this species.
    We have no data concerning the impacts of scientific research on 
this species along its migratory route or on its wintering grounds, but 
there is no reason to suspect those activities have or will produce 
significant adverse impacts on the species.
    In summary, the best available scientific data indicate that there 
are no significant impacts occurring to the species from 
overutilization for commercial, recreational, scientific, or 
educational purposes.

C. Disease or Predation

    We found no evidence to suggest that avian diseases or parasites 
are affecting cerulean warblers beyond normal baseline levels.
    The possible increased impacts of predation and nest parasitism are 
believed to be caused by changes in habitat quality. Therefore, these 
impacts are discussed under Factor A, above.

D. The Inadequacy of Existing Regulatory Mechanisms

    Existing regulatory mechanisms that could provide some protection 
for the cerulean warbler include: (1) United States Federal laws, 
regulations, and Executive Orders; (2) Canadian Federal and Provincial 
Laws and Regulations; and (3) State wildlife laws, which are discussed 
(1) U.S. Federal Laws, Regulations, and Executive Orders
    The Migratory Bird Treaty Act (MBTA; 16 U.S.C. 703-712) prohibits 
``take'' of any migratory bird. ``Take'' is defined as to pursue, hunt, 
shoot, wound, kill, trap, capture, or collect, or attempt to pursue, 
hunt, shoot, wound, kill, trap, capture, or collect.
    The National Environmental Policy Act (NEPA; 42 U.S.C. 4321 et 
seq.) requires all Federal agencies to formally document, consider, and 
publicly disclose the environmental impacts of their actions and 
management decisions. NEPA documentation of these impacts is provided 
in an environmental impact statement, an environmental assessment, or a 
categorical exclusion, and may be subject to administrative or judicial 
appeal. In NEPA documents, Federal agencies may present scientific 
studies, evaluations, and management decisions involving actions that 
may impact the cerulean warbler or its habitat. Some Federal agencies 
may be required by their regulations, policies, and guidance to perform 
specific assessments under NEPA for actions that could impact the 
cerulean warbler. Examples include biological evaluations addressing 
actions by the U.S. Forest Service on national forests where the 
cerulean warbler is identified as a sensitive species by the Regional 
    The Multiple-Use Sustained-Yield Act of 1960, as amended (MUSY; 16 
U.S.C. 528-531) provides direction that the national forests be managed 
using principles of multiple uses and to produce a sustained yield of 
products and services. Specifically, MUSY provides policy that the 
national forests are established and shall be administered for outdoor 
recreation, range, timber, watershed, and wildlife and fish purposes. 
Land management for multiple uses necessarily raises competing and 
conflicting issues. MUSY provides direction to the Forest Service that 
wildlife, including the cerulean warbler, is a value that must be 
managed for, though discretion is given to each forest when considering 
the value of this species relative to the other uses for which it is 
managing. Although MUSY could provide some protection for the warbler, 
it does not have any provisions specific to the conservation of the 
warbler or its habitat.
    The National Forest Management Act (NFMA) as amended (16 U.S.C. 
1600-1614) is the primary law governing the administration of national 
forests by the U.S. Forest Service. NMFA requires all units of the 
National Forest System to have a Resource Management Plan (RMP), to 
revise the plans whenever significant changes occur in a unit, and to 
update the plans at least once every 15 years. The purpose of the RMP 
is to guide and set standards for all natural resource management 
activities over time. NFMA requires the Forest Service to incorporate 
standards and guidelines into RMPs, including provisions to support and 
manage plant and animal communities for diversity, and the long-term 
rangewide viability of native and desired nonnative species. Several 
national forests have identified the cerulean warbler as a ``sensitive 
species,'' which involves an additional assessment of the impact of 
individual management actions by the national forest on the cerulean 
warbler. National forests that have identified the cerulean warbler as 
a sensitive species have current information on the presence and 
condition of the warbler and its habitat on the national forests and 
within individual units where management actions are planned. Surveys 
for cerulean warblers may be conducted prior to undertaking management 
actions or to monitor population trends of cerulean warblers, including 
national forests where the species is not designated as a sensitive 
species. The cerulean warbler has also been identified as a Management 
Indicator Species on several national forests. In these cases, the 
cerulean warbler functions as a biological indicator of desired forest 
condition, and results in a higher level of awareness of the species' 
life history and habitat needs, which are considered during analysis of 
the impacts of site-specific management activities by the national 
forest. The NFMA allows for habitat management specifically to benefit 
cerulean warblers on national forests within the species' historical 
    The Surface Mining Control and Reclamation Act (SMCRA; 25 U.S.C. 
1201) addresses the necessary approvals for surface mining operations, 
as well as inspection and enforcement of mine sites until reclamation 
responsibilities are completed and all performance bonds are released. 
This law, which regulates the recovery of coal by

[[Page 70729]]

mountaintop removal mining (commonly referred to as mountaintop 
mining), is administered by the U.S. Department of the Interior's 
Office of Surface Mining (OSM). SMCRA permits for mountaintop removal 
mining may be issued by the OSM or by individual States only if it has 
been shown that the proposed mining activities will satisfy general 
performance standards applicable to all surface coal mining operations. 
In the Appalachian States where mountaintop mining occurs, the SMCRA 
regulatory program has been delegated by the Federal Government to 
State agencies, except in Tennessee (Copeland 2005, p. 2). Among the 
general performance standards, SMCRA addresses disturbances at the 
mine-site and in associated offsite areas and approximate original 
contour (AOC) requirements, as well as the quality and quantity of 
water in surface and ground water systems both during and after surface 
coal mining operations (Copeland 2005, p. 2).
    Before commencing mountaintop removal mining, a coal company must 
post a bond to pay for the reclamation of the site. To get this bond 
released, the company must reclaim the site to meet the standards set 
by the State responsible for implementing SMCRA. Reclamation at 
mountaintop mine sites has focused on erosion prevention and backfill 
stability and not on reclamation with trees. The compacted backfill 
material that is normally used for reclamation hinders tree 
establishment and growth. Furthermore, reclaimed soils are more 
conducive for growing grasses, which outcompeted tree seedlings; 
grasses are often planted as a fast-growing vegetative cover to reduce 
erosion. As a result, natural succession by trees and woody plants on 
reclaimed mined land (with intended post-mining land uses other than 
forest) is slowed (Environmental Protection Agency 2005, p. 4; Handel 
et al. 2003, p. 12).
    Section 404 of the Clean Water Act (33 U.S.C. 1251 et seq.) is 
another principal environmental law involved in the regulation of 
mountaintop mining. The section 404 permit program, which regulates the 
discharge of dredge and fill material into waters of the United States, 
applies to the disposal of excess overburden associated with 
mountaintop mining. These permits are issued by the U.S. Army Corps of 
Engineers with oversight by the U.S. Environmental Protection Agency. 
In the past, the Corps of Engineers has generally permitted the 
disposal of mountaintop mining fill under Nationwide Permit 21 (NWP 
21). This overburden has frequently been deposited in adjacent stream 
valleys in a process known as valley fill. This nationwide permit 
authorizes discharges from surface coal mining activities that result 
in no more than minimal impacts (site-specifically and cumulatively) to 
the aquatic environment.
    Cerulean warblers and their habitat are impacted by mountaintop 
mining both by the clearing of forests to remove the coal and by the 
associated disposal of mine overburden in adjacent valleys. In 
addition, the practice of establishing non-forested habitats, 
especially grasses, on reclaimed mine lands that were previously 
forested has further prevented the restoration of cerulean warbler 
habitat at these sites. The conservation of the cerulean warbler could 
be improved by additional focus by the regulatory programs under SMCRA 
and section 404 of the CWA on the additional protection and improved 
reclamation of the species' habitat.
    The U.S. Department of the Interior (National Park Service and Fish 
and Wildlife Service) manages lands containing cerulean warblers. The 
National Park Service Organic Act (39 Stat. 535; 16 U.S.C. 1, 2, 3, and 
4), states that the NPS will administer areas under their jurisdiction 
``* * * by such means and measures as conform to the fundamental 
purpose of said parks, monuments, and reservations, which purpose is to 
conserve the scenery and the natural and historical objects and the 
wildlife therein and to provide for enjoyment of the same in such 
manner and by such means as will leave them unimpaired for the 
enjoyment of future generations.'' Several National Parks are known to 
contain cerulean warbler populations and habitat.
    The National Wildlife Refuge System Administration Act (NWRSAA; 16 
U.S.C. 668d-668e) provides guidelines and directives for administration 
and management of all areas in the National Wildlife Refuge System. 
National Wildlife Refuges (NWR) are managed for species conservation, 
consistent with the direction of the NWRSAA, as amended, and related 
Service policies and guidance.
    The Sikes Act (16 U.S.C. 670a-670o; 74 Stat 1052) authorizes the 
Secretary of Defense to develop cooperative plans for conservation and 
rehabilitation programs on military reservations and to establish 
outdoor recreation facilities. Under the authority of the Sikes Act, 
military installations prepare Integrated Natural Resources Management 
Plans (INRMP) that address how fish and wildlife resources will be 
managed. These plans reflect the mutual agreement of the military 
facility, the Service, and the appropriate State fish and wildlife 
agency on the conservation, protection and management of fish and 
wildlife resources.
    Executive Order 13186 (entitled Responsibilities of Federal 
Agencies To Protect Migratory Birds), signed by President Clinton on 
January 10, 2001, addresses the commitment by all Federal departments 
and agencies to conserve migratory birds in the United States. 
Executive Order 13186 directs Federal agencies that implement actions 
having a measurable negative effect on migratory bird populations to 
develop and implement a Memorandum of Understanding with the Service 
that will promote migratory bird conservation. The Executive Order 
identifies 15 conservation measures that each Federal agency is 
encouraged to implement. These measures involve a range of actions to 
be implemented by Federal agencies, including: (1) Integrating 
migratory bird conservation into agency plans, programs, and actions, 
including environmental analyses under NEPA; (2) adopting principles 
and practices in the design of agency actions that avoid or minimize 
adverse impacts on migratory birds; (3) incorporate comprehensive 
migratory bird programs, such as Partners-In-Flight, North American 
Waterfowl Management Plan, and North American Bird Conservation 
Initiative into agency management plans and guidance; (4) restore and 
enhance migratory bird habitat; (5) develop partnerships with non-
Federal entities to further bird conservation; and (6) promote research 
and information exchange related to migratory birds, including 
coordinated inventorying and monitoring on agency lands. The first two 
Memorandum of Understandings under EO 13186, with the Department of 
Defense and Department of Energy, were signed on July 12, 2006.
(2) Canadian Federal and Provincial Laws and Regulations
    All migratory birds (including cerulean warblers), nests, eggs, and 
their parts in Canada are protected by the Migratory Bird Conservation 
Action of 1994, as amended. This law is similar to the Migratory Bird 
Treaty Act in that it prohibits the taking, possession, transportation, 
and sale of migratory birds and establishes penalties for violations, 
but it provides no direct protections for migratory bird habitats. This 
Canadian law implements the 1916 Convention between the United States 
and Great Britain (for Canada) for the protection of migratory birds.
    In Canada and the two Provinces where the species occurs (Ontario 
and Quebec), the cerulean warbler is a

[[Page 70730]]

Species of Special Concern under schedule 1 of the Species at Risk Act 
(Canada Gazette, Part III, Chapter 29, Vol. 25, No. 3 2002). Passed in 
2002, the Species at Risk Act (SARA) is similar to the Endangered 
Species Act. Under SARA, a Species of Special Concern is a ``wildlife 
species that may become a threatened or an endangered species because 
of a combination of biological characteristics and identified threats'' 
(section 2, Species at Risk Act, 2002). Only those species listed as 
endangered, threatened, or extirpated are protected by the prohibitions 
of SARA. The prohibitions and other regulatory provisions of SARA do 
not apply to Species of Special Concern; however, SARA does require the 
preparation of management plans for Species of Special Concern, 
including measures for the conservation of the species and its habitat 
(SARA, sections 65-72). The objective of implementing these management 
plans is to prevent Species of Special Concern from becoming a 
threatened or endangered species.
(3) State Laws
    All of the 33 States within range of the cerulean warbler have 
provisions in their Wildlife Codes that protect non-game migratory 
birds, including the cerulean warbler. These State laws generally 
prohibit the killing, capture, possession, and sale of migratory birds 
without proper authorization from the State wildlife agency. Delaware 
and Rhode Island list the cerulean warbler as a State Endangered 
Species and the species is listed as a State Threatened Species in 
Illinois and Wisconsin. The designation as Endangered or Threatened by 
these States provides additional protection, prohibitions, and 
conservation emphasis in accordance with their respective State 
Wildlife Codes. Tennessee has designated the cerulean warbler as a 
Species in Need of Management, which provides some additional 
protection and conservation emphasis. Eleven States have placed the 
cerulean warbler in a category of Species of Special Concern, Species 
of Special Interest, or Rare. In most of these States, these categories 
do not provide the cerulean warbler additional protection or 
prohibitions beyond what is in their general Wildlife Codes. The 
protections provided the cerulean warbler by the State wildlife laws 
generally do not include regulatory provisions to protect its habitat.

Summary of Factor D

    We believe those existing laws, regulations, and Executive Orders 
that involve the management of Federal forest and wildlife resources 
(MUSY, NFMA, National Wildlife Refuge System Administration Act, 
National Park Service Organic Act, Sikes Act, and Executive Order 
13186) are not inadequate mechanisms to conserve the cerulean warbler 
and its habitat on these specific Federal lands. These laws provide the 
flexibility and framework to maintain or adjust habitat management 
objectives that benefit the cerulean warbler. Although these laws and 
regulations contain sufficient provisions for the conservation of the 
cerulean warbler, there are limitations in the ability of agencies to 
implement them in a manner most beneficial to the species they are 
intended to benefit or protect (for example, cerulean warblers). For 
instance, limited agency budgets, conflicting policies, lack of public 
support, and other factors can deter achieving the full management 
flexibility and benefits.
    As discussed above, we believe that certain existing laws 
pertaining to the management of specific Federal lands in the United 
States are not inadequate regulatory mechanisms to conserve the 
cerulean warbler and its habitat. We also believe that some existing 
regulatory mechanisms are inadequate in protecting the cerulean warbler 
and its habitat. An example of this is the continued loss, without 
adequate reclamation, of cerulean warbler breeding habitat from 
mountain top mining, despite the application of the Surface Mining 
Control and Reclamation Act and section 404 of the Clean Water Act to 
these actions. Besides the regulation of mountain top mining under 
SMCRA and section 404 of the Clean Water Act, we are not aware of any 
Federal or State regulatory mechanisms that provide for the 
conservation of cerulean warbler habitat on the extensive private 
forest lands within the species' breeding range. Furthermore, we are 
not aware of any laws that protect the cerulean warbler or its habitat 
in its non-breeding (winter) range in South America.

E. Other Natural or Manmade Factors Affecting Its Continued Existence

    We identified several other potential threats, but available 
information is insufficient to determine that these factors have 
contributed to or will likely cause a population level decline in 
cerulean warblers. These factors are:

Mortality From Collisions With Structures

    The collision of birds with structures during migration has been 
well documented, especially since this issue began receiving major 
emphasis in the 1970s (Manville in press, p. 2). Structures that pose a 
collision hazard to birds include buildings, communication towers 
(cell, radio, and television), wind power turbines, smoke stacks, and 
power lines. There is no confirmed, validated number or accurate 
estimate of the total number of birds killed by these structures, but 
estimates range from four to five millions of birds up to 40 million 
(Shire et al. 2000, p. 3; Manville in press, p. 3). Few studies have 
been carried out to document cerulean warbler mortalities from tall 
structures. The analysis by Shire et al. (2000, p. 9) of 149 reports of 
tower-caused mortalities identified 164 cerulean warblers killed at 5 
sites. At this time, there have been insufficient studies conducted for 
the Service to be able to evaluate the threat of tall structures to 
cerulean warblers.

Localized Areas of Calcium Depletion Because of Acid Rain

    Atmospheric acid deposition (acid rain) has been linked with 
reduced abundance of some songbird species (Hames et al. 2002, pp. 
11238-11239; Hames et al. 2006). Under some conditions, calcium, which 
is needed for egg production, is leached from basic soils. Researchers 
have not studied the potential effect of this phenomenon on cerulean 

Reduction in Prey Availability Because of Climate Change

    Evidence from Europe indicates that climate change may advance the 
phenology of insect populations in temperate regions, and the peak in 
insect prey abundance may therefore occur before long-distance 
migratory birds arrive from the tropics, and prior to their need for 
abundant food for their young (Both et al. 2006, pp. 81-82; and Both 
and Visser 2001, pp. 296-298). We know of no information that indicates 
this is currently a problem for cerulean warblers.

Small Population Phenomena

    We found no evidence that genetic isolation (Veit et al. 2005) or 
other phenomena associated with small populations are affecting 
cerulean warblers.

Extinction Risk Analysis

    Since our knowledge of the factors that may lead to extinction is 
incomplete, and because extinction is inherently a probabilistic event 
(it may or may not happen at any specified time due to random events), 
extinction risk is best described by a likelihood or probability. The 
most direct method available to estimate extinction likelihood for 
cerulean warblers is to

[[Page 70731]]

calculate forward from the current total abundance using the average 
annual trend in abundance. The best available estimate for current 
global population size of cerulean warblers is based on the Partners in 
Flight estimate of 560,000 birds in 1995 (Rich et al. 2004, Appendix 
A--pp. 69-77), decreased by 11 years of declines that average 3.2 
percent annually, resulting in an estimate of about 390,000 birds in 
2006. Although the Partners in Flight estimate was imprecise (plus or 
minus 50 percent of the estimate) and may also be biased, most likely 
underestimating abundance (see Population Size Estimate Based on the 
Partners in Flight Method above), it is the best available data at the 
time of this finding. Expressed as a more general figure that reflects 
the substantial uncertainty about actual population size, we conclude 
that the current population of cerulean warblers may be around a half-
million birds, and perhaps much larger. For the extinction risk 
analysis that follows, however, an estimate of 400,000 birds was used 
for 2006.
    If the average 3.2 percent per year decline continues without 
variance, a population of 400,000 birds will decrease to approximately 
200,000 in 20 years, 80,000 in about 50 years, and 15,000 in 100 years. 
In reality, population trends vary from year to year so future 
population change could be greater or less than these median or 
``deterministic'' estimates. Thogmartin (2006, pp. 3-4) applied a 
statistical method called diffusion approximation (described in Dennis 
et al. 1991, and Holmes 2001, 2004) to the BBS data to estimate the 
probability of cerulean warbler population change to different levels 
over time. This method requires estimates for initial population size, 
average annual trend, and the year-to-year variance in population 
counts to project a statistical distribution of potential future 
population sizes over time--given the key assumption that past year-to-
year fluctuations represent the plausible range (a statistical 
distribution) of annual changes that can happen randomly in the future. 
Given the available 40-years of BBS abundance indices and assuming the 
current population size is nearly 400,000 birds, Thogmartin (2006, p. 
18) projected an 83 percent chance that the population will decrease to 
40,000 birds (90 percent decline) in 100 years. The likelihood of 
extinction, modeled as a 99.999 percent population reduction or a 
decline to a few hundred birds, was close to zero in 100 years 
(Thogmartin 2006, p. 18). To date, there have been no published 
diffusion approximation models or other extinction risk analyses for 
the cerulean warbler. Therefore, the work conducted by Thogmartin 
(2006) is the best scientific information currently available on this 
    Thogmartin (2006, p. 19) subsequently evaluated whether the 
likelihood of population declines was sensitive to the uncertainty 
about current population size. He found that the estimated 
probabilities of declines differed for projections using the upper and 
lower ends of the interval estimated by Partners in Flight extrapolated 
to 2006, that is, 200,000 or 600,000 birds rather than the median or 
``best'' estimate of 400,000 birds.
    Thogmartin (2006, p. 20) also completed calculations for the 
eastern or Appalachian portion of the species' range separately from 
the regions farther west to consider possible regional differences. 
Initial population in the east (Bird Conservation Regions 13 and 27 to 
30) was 345,000 birds (86 percent of total abundance), and in the west 
(Bird Conservation Regions 22 to 25) it was 55,000 birds (14 percent of 
total abundance) (relative abundance between regions from Partners in 
Flight figures; Rich et al. 2004, Appendix A--pp. 69-77). Projected 
likelihood of a 90 percent decline in 100 years in these two regions 
was about 70 percent and 90 percent, respectively (Thogmartin 2006, p. 
20). The projected risk of decline was actually lower for the 
Appalachian region alone than for the species rangewide due to 
relatively less year-to-year variance in counts in this higher density 
area compared with the estimates that include very small sample size 
counts in the western parts of the range.
    These calculations are helpful in understanding the consequences of 
a continuation of the historical trend, but they do not address whether 
underlying population dynamics will differ as time passes. The 100-year 
time frame in Thogmartin's (2006) analysis is simply a convention from 
theoretical modeling (e.g., Dennis et al. 1991, and Holmes 2001, 2004) 
and does not address the reliability of projecting that far forward 
based only upon historical data. It is clear that the farther into the 
future we attempt to predict, the less confident we can be that the 
historical trend will persist. Future population sizes will vary due to 
a variety of factors, both random events and progressive changes in 
causal environmental factors that we cannot foresee at this time. Thus 
we are more confident that the historical trends will continue over the 
next few decades, than over longer time frames such as 100 years.

Determination of Status Under the Endangered Species Act

    The Act defines an endangered species as ``any species which is in 
danger of extinction throughout all or a significant portion of its 
range * * *'' (16 U.S.C. 1533 Sec.  3(6)). The Act defines a threatened 
species as ``any species which is likely to become an endangered 
species within the foreseeable future throughout all or a significant 
portion of its range'' (16 U.S.C. 1533 Sec.  3(20)). For each species 
considered for listing, the Service must review the best available 
information on the likelihood of extinction over time and determine 
case-by-case whether the present risk is sufficient to constitute a 
``danger'' of extinction, or whether projected future risk is 
``likely'' to become a danger of extinction under ``foreseeable'' 
    The cerulean warbler has been declining by about 3 percent 
annually, on average, for the last 40 years, including within the 
Appalachian core breeding area (see Population Size and Trends). The 
biological factors most likely to have caused this trend include: (1) 
Reduction in available nesting sites and suitable breeding territory 
characteristics because of loss or degradation of nesting habitat; (2) 
reduction in foraging success resulting from decreased prey abundance, 
primarily on the wintering ground in South America; (3) increased 
predation throughout the species' annual range and nest parasitism of 
cerulean warblers in the breeding grounds resulting from habitat 
fragmentation; and (4) increased mortality during migration due to 
coastal forest habitat loss (see The Present or Threatened Destruction, 
Modification, or Curtailment of Its Habitat or Range). The Service 
further concludes that those factors are ongoing and thus will likely 
continue to cause the species to decline, probably at a similar rate, 
as in the recent past. The best available projection for future trends 
is to assume that the persistent rate of decline documented by the BBS 
over the past 40 years will continue within the estimated credible 
interval, between 2.0 and 4.2 percent per year.
    Since projections derived from the BBS data indicate effectively no 
chance for this species to become extinct in the next 100 years unless 
conditions change beyond what we can anticipate (see Extinction Risk 
Analysis above), we do not believe this species is likely to become 
endangered within the foreseeable future. In short, a species with a 
current population of perhaps half a million birds and quite possibly 
more, declining chronically by 2 to 4

[[Page 70732]]

percent annually, is neither in danger of extinction now or likely to 
become in danger of extinction in the future that we can reasonably 
foresee. Thus, the Service concludes that the cerulean warbler does not 
presently qualify for protection as an endangered species or a 
threatened species under the Act and the petitioned action is not 


    The cerulean warbler population is decreasing by approximately 
three percent per year across its breeding range. A combination of 
habitat losses and structural changes and fragmentation in remaining 
forest habitats across the species' annual range are most likely the 
primary causal factors contributing to this decline. The available 
information on potential causal factors indicates these threats are, 
for the most part, both already operating and will continue to operate 
in the foreseeable future. Hence, we anticipate continued, gradual 
decline of this species. We also conclude, however, that abundance will 
remain high enough that the species effectively is in no danger of 
extinction in the near term, and that, if the historical trend 
continues, tens of thousands of cerulean warblers will remain in 100 
    The Act defines an endangered species as a species in danger of 
extinction in all or a significant portion of its range. Given the 
available information including a population size approaching half a 
million, perhaps more, cerulean warblers are not currently facing 
extinction across their range. We do not consider the westernmost parts 
of the range, where local extirpation could possibly occur in the next 
few decades, as significant from the perspective of defining the entire 
species as endangered, because those portions already contain only a 
small fraction of the total population and their loss would not put the 
remainder of the range at risk of extinction. Therefore, those 
westernmost areas are not a significant portion of the species' range.
    A threatened species, as defined in the Act, is a species likely to 
become endangered in the foreseeable future in all or a significant 
portion of its range. We do not believe that it is likely (more likely 
to happen than not) that cerulean warblers will decline to a point 
where they are endangered or facing extinction within the foreseeable 
future. This is our conclusion, even if conditions were on the worst 
end of the range for trends and abundance rather than the median or 
'best' estimates indicated by 40 years of breeding bird surveys. Again, 
we do not consider those portions of the range with currently marginal 
populations that may become at risk of extinction in less than 100 
years as significant to the entire species' projected extinction risk, 
and thus they are not a significant portion of the range as used in the 
definition of threatened. Based on the trends recorded in breeding 
population counts and the assumption that those declines and their 
causal factors will continue unabated, the likelihood of species 
extinction, even as far into the future as 100 years, appears close to 


    We have carefully assessed the best scientific and commercial 
information available regarding the past, present, and future threats 
faced by the cerulean warbler. We reviewed the petition, available 
published and unpublished scientific and commercial information, and 
information submitted to us during the public comment period following 
our 90-day petition finding. This finding reflects and incorporates 
information we received during the public comment period and responds 
to significant issues. We also consulted with recognized experts on the 
cerulean warbler and its habitat from Federal and State agencies, non-
governmental conservation organizations, academia, and the forest 
industry. On the basis of this review we have determined that the 
listing of cerulean warbler as threatened or endangered is not 
warranted under the Endangered Species Act, as amended.
    If new impacts to the species arise in the future or if the Service 
finds that the populations are declining significantly faster than they 
were found to have done in the past or that threats are of greater 
magnitude than they are currently, the Service can reexamine the 
listing status of the cerulean warbler. We will continue to monitor the 
status of the cerulean warbler and its habitat and will continue to 
accept additional information and comments from all governmental 
agencies, the scientific community, industry, or any other interested 
party concerning this finding.

Future Conservation

    Even though we have determined in this 12-month petition finding 
that the cerulean warbler does not meet the definition of endangered or 
threatened, we believe it is essential that existing conservation 
efforts for the cerulean warbler be pursued and new actions implemented 
to address the steady decline of the species. Besides the ongoing 
conservation efforts addressed under Factor A of this finding, there 
are several important emerging efforts and programs, all involving 
multiple, diverse partners. We did not rely on these future 
conservation actions in our determination that listing the cerulean 
warbler is not warranted and, therefore, we did not evaluate them under 
our 2003 Policy for Evaluation of Conservation Efforts When Making 
Listing Decisions (68 FR 15100; March 28, 2003).
    In 2005, the Service's Migratory Bird Program initiated a new 
strategy to better measure its success in achieving its bird 
conservation priorities and strategies. The Focal Species Strategy 
involves campaigns for selected species to provide explicit, strategic, 
and adaptive sets of conservation actions required to return species to 
healthy and sustainable levels. The Service's list of Birds of 
Management Concern is a subset of species protected by the MBTA that 
pose special management challenges due to a variety of reasons. There 
are currently 412 species, subspecies, or populations of birds on the 
Birds of Management Concern list, including the cerulean warbler. 
Through a comprehensive review of the birds on this list and using a 
combination of evaluation factors, the Service's Migratory Bird Program 
identified 139 bird species for the development of Focal Species 
Strategies. The cerulean warbler is in the first group of birds to have 
focal species strategies developed in Fiscal Years 2005 and 2006. The 
cerulean warbler Focal Species Strategy, the first draft of which is 
scheduled to be completed in September 2006, will utilize management 
and conservation documents to form an action plan (a species-specific 
mix of monitoring, research, assessment, habitat and population 
management, and outreach) necessary to accomplish: (1) Desired status; 
(2) a summary of the responsibilities for actions within and outside 
the Migratory Bird Program; (3) a focus of Service resources on 
implementing those actions; and (4) communications to solicit support 
and cooperation for partners inside and outside the Service. The 
engagement of partners and stakeholders is essential for developing and 
implementing this focal species strategy for the future conservation of 
the cerulean warbler. The Service's Migratory Bird Program has involved 
cerulean warbler experts and other partners in identifying the future 
desired status and priority conservation measures for the focal species 
strategy. The Cerulean Warbler Focal Species Strategy will provide an 
important ``blueprint'' for use by Federal and State agencies, 
conservation organizations, researchers, corporations, private 
landowners, groups like the

[[Page 70733]]

Cerulean Warbler Technical Group (see below), and other bird 
conservation programs, such as the Important Bird Areas, in 
implementing actions for the conservation of the cerulean warbler.
    BirdLife International's Important Bird Areas Program (administered 
by the National Audubon Society in the United States) identifies, 
monitors, and conserves a global network of Important Bird Areas (IBA) 
that provide important habitat for birds and focuses conservation 
efforts at these sites. The IBA Program recognizes that habitat loss 
and fragmentation are the most serious threats facing populations of 
birds. By working through partnerships, principally the North American 
Bird Conservation Initiative, to identify those places that are 
essential to birds, the National Audubon Society and its many IBA 
partners hope to minimize the effects of habitat loss on birds. The 
identification and inventory of IBAs has been a particularly effective 
way to prioritize conservation efforts. IBAs are key sites for 
conservation, often able to be conserved in their entirety and often 
already part of a conservation-area network. There are approximately 
112 IBAs in the United States and six in the Canadian Province of 
Ontario that contain the cerulean warbler. Several of these IBAs 
contain large cerulean warbler populations and important breeding 
habitats (for example, Northern Montezuma Wetlands IBA in New York and 
Southern Cumberland Mountains IBA in Tennessee). Within the cerulean 
warbler's wintering range, there are 30 IBAs that contain the species 
(14 in Colombia, 14 in Venezuela, and 2 in Ecuador).
    The State Wildlife Grants Program (SWG; administered by the 
Service's Federal Assistance Program), provides Federal funds to every 
State and territory for the development and implementation of programs 
that benefit wildlife and their habitat, including species that are not 
hunted or fished. A primary focus of the SWG Program is to target funds 
to States to implement conservation actions for rare or declining 
wildlife species to prevent these species from becoming endangered in 
the future. To be eligible for these funds, States and territories were 
required to submit to the Service by October 1, 2005, a State Wildlife 
Action Plan (also called a Comprehensive Wildlife Conservation 
Strategy) that, at a minimum, addressed the following seven items: (1) 
Information on the distribution and abundance of wildlife species, 
including low and declining populations, that are indicative of the 
diversity and health of the State's wildlife; (2) descriptions of 
locations and relative condition of key habitats and community types 
essential to conservation of these species; (3) descriptions of 
problems which may adversely affect these species; (4) descriptions of 
conservation actions proposed to conserve these species and habitats 
and priorities for implementing actions; (5) proposed plans for 
monitoring these species and their habitats; (6) descriptions of 
procedures to review the Plan; and (7) plans for coordinating the 
development, implementation, review, and revision of the Plan. In 
appropriating funds for the SWG Program, Congress directed the States 
to place appropriate priority on ``those species of greatest 
conservation need''. In defining the species required by number 1 
above, most State Wildlife Action Plans contain a list and description 
of the Species of Greatest Conservation Need (SGCN).
    All 33 States within the range of cerulean warbler have completed 
their State Wildlife Action Plans. These plans have been reviewed and 
approved by the Service. Of these States, 23 have identified the 
cerulean warbler as a SGCN. In addition, nine States' Plans have 
identified priority conservation and management objectives and actions 
for the cerulean warbler. The actions in these nine Plans include 
monitoring populations, managing forests to provide high-quality 
nesting habitat, implementing measures to maintain appropriate habitat 
patch size and reduce forest fragmentation, and collaborating with 
others to conserve the species' wintering habitat in South America.
    The integrated bird conservation efforts under the North American 
Bird Conservation Initiative and Partners-In-Flight will benefit the 
future conservation of the cerulean warbler. Concept Plans and Bird 
Conservation Plans have been completed or are being developed in Bird 
Conservation Regions (BCR) and Physiographic Areas that contain 
cerulean warblers. These plans have specific actions pertaining to the 
cerulean warbler, especially in the Appalachian Mountains Bird 
Conservation Region. This BCR, encompassing 42 million ha (105 million 
ac), contains the core breeding population of cerulean warbler and is 
essential to the future conservation of the species. A future critical 
need in this BCR is the establishment of a coordinator to integrate and 
expand conservation actions for the cerulean warbler and other birds in 
this region. The Partners-In-Flight program is addressing the decline 
of the cerulean warbler and its habitat in both its breeding and non-
breeding range.
    We believe these and other existing and emerging collaborative 
efforts provide an excellent opportunity to reverse the steady decline 
of the cerulean warbler and preclude the future need to list. The 
Service believes it is important to continue strong support for 
monitoring efforts for this species, especially long-term monitoring 
programs like the Breeding Bird Survey that provides valuable trend 
information. Tracking population changes is vital to the future 
conservation of the cerulean warbler and other neotropical migratory 
birds. We will provide strong support and develop partnerships around 
the Service's Cerulean Warbler Focal Species Strategy, which will 
become an important blueprint for helping to reverse the warbler's 
population decline through proactive conservation efforts. We will also 
continue to support and provide assistance to the Cerulean Warbler 

Technical Group because it has the opportunity to effect positive 
change for the species through its scientifically driven collaborative 
efforts. We will support and provide technical assistance in using the 
other integrated bird conservation programs (Partners-In-Flight, North 
American Bird Conservation Initiative, and Important Bird Areas) and 
the State's Wildlife Action Plans to further promote the future 
conservation of the cerulean warbler.


    A complete list of references used in the preparation of this 
finding is available upon request from Columbia Ecological Services 
Field Office (see ADDRESSES) or can be downloaded from our Web site at 


    This finding was written by biologists from the Service's 
Endangered Species and Migratory Bird Programs in Region 3, 4, and 5 
and Washington, DC.


    The authority for this action is the Endangered Species Act of 
1973, as amended (16 U.S.C. 1531 et seq.).

    Dated: November 28, 2006.
Kenneth Stansell,
Acting Director, U.S. Fish and Wildlife Service.
[FR Doc. E6-20530 Filed 12-5-06; 8:45 am]