[Federal Register: October 23, 2002 (Volume 67, Number 205)]
[Proposed Rules]               
[Page 65083-65086]
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; 90-Day Finding on 
a Petition to List the Cerulean Warbler as Threatened With Critical 

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Notice of 90-day petition finding and initiation of status 


SUMMARY: We, the U.S. Fish and Wildlife Service (Service), announce a 
90-day finding on a petition to list the cerulean warbler (Dendroica 
cerulea) as threatened, under the Endangered Species Act (Act) of 1973, 
as amended (16 U.S.C. 1531 et seq.). We find that the petition 
presented substantial information indicating that listing this species 
may be warranted. We are initiating a status review to determine if 
listing the cerulean warbler is warranted.

DATES: The finding announced in this document was made on September 24, 
2002. To be considered in the 12-month finding for this petition, 
comments and information should be submitted to the Service by January 
21, 2003.

ADDRESSES: Data, information, comments, or questions should be 
submitted to the Field Supervisor, Ecological Services Field Office, 
U.S. Fish and Wildlife Service, 608 East Cherry Street, Room 200, 
Columbia, MO 65201, or by facsimile to (573) 876-1914. The complete 
petition finding, supporting literature, and comments are available for 
public inspection, by appointment, during normal business hours at the 
above address.

FOR FURTHER INFORMATION CONTACT: Amy Salveter at the Columbia, 
Missouri, Field Office see ADDRESSES), or at (573) 876-1911, extension 



    Section 4(b)(3)(A) of the Endangered Species Act (Act) of 1973, as 
amended (16 U.S.C. 1531 et seq.), requires that the U.S. Fish and 
Wildlife Service (Service) make a finding on whether a petition to 
list, delist, or reclassify a species presents substantial scientific 
or commercial information to demonstrate that the petitioned action may 
be warranted. This finding is based on information contained in the 
petition, supporting information submitted with the petition, and 
information otherwise available to us at the time we make the finding. 
To the maximum extent practicable, we make this finding within 90 days 
of the receipt of the petition, and the finding is to be published 
promptly in the Federal Register. If we find that substantial 
information was presented, we commence a review of the status of the 
species. After considering the comments and information submitted to us 
during the status review comment period following this 90-day finding, 
we will issue an additional finding (i.e., the 12-month finding) 
determining whether listing is in fact warranted.
    On October 31, 2000, we received a petition to list the cerulean 
warbler as a threatened species and to designate critical habitat for 
the species pursuant to the Act. The petition was submitted by the 
Southern Environmental Law Center, which acted on its own behalf, and 
for 27 other organizations, and 7 scientists.
    The letter clearly identified itself as a petition, and included 
the name, signature, and address of the representative of the parties 
submitting the petition. The petition referenced supporting information 
on the species' description, natural history, habitat, and population 
status. It also presented information on threats to the cerulean 
warbler including present or threatened destruction, modification, or

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curtailment of the species' habitat or range; predation; the inadequacy 
of existing regulatory mechanisms to protect the species; and other 
natural or manmade factors affecting the species' continued existence. 
This notice announces and summarizes our 90-day finding for the October 
30, 2000, petition.
    The cerulean warbler is a neotropical migratory bird that winters 
in montane forests of northern South America and breeds in deciduous 
forests of the eastern United States and southern Canada. The breeding 
range of cerulean warbler generally extends from the eastern Great 
Plains in eastern North and South Dakota, Nebraska, Kansas, and 
Oklahoma; south to Arkansas, Mississippi, Tennessee, northern Alabama 
and Georgia, and South Carolina; and north to Massachusetts, southern 
Quebec, southeastern Ontario, Michigan, Wisconsin, and central 
Minnesota (Hamel 2000a, Rosenberg et al. 2000). Breeding cerulean 
warblers are found in the Mississippi and Ohio River valleys, but 
appear to be concentrated in the upper Ohio valley in West Virginia and 
western Pennsylvania (Hamel 2000a, 2000b, Rosenberg et al. 2000). 
During migration, the birds pass through the southern United States, 
across the Gulf of Mexico to the highlands of Central America, and on 
to South America. Cerulean warblers winter in the middle and lower 
elevations of the subtropical zone of the eastern slope of the Andes 
and other mountains in northern South America (Hamel 2000a). Their 
winter range generally extends from Colombia and Venezuela south, 
mostly along the eastern slope of the Andes, to southern Peru and 
perhaps northern Bolivia (AOU 1998).
    The petitioners assert that the cerulean warbler is threatened by 
destruction, modification, or curtailment of habitat or range by 
logging on public and private lands, construction of water projects 
e.g., reservoirs, sewer lines and stream channelization), agricultural 
practices and urbanization through: (1) Loss and fragmentation of 
breeding habitat in the United States e.g., loss of tall, mature 
deciduous forest, especially extensive bottomland hardwood forest 
throughout the floodplain of the Lower Mississippi River Alluvial 
Valley), (2) loss of winter habitat (within a relatively narrow 
elevation zone of the Andes in South America), and (3) loss of 
migratory habitat e.g., development of property along the beaches of 
Texas, Louisiana, and the Florida panhandle). According to the 
petitioners, logging creates smaller and more fragmented forest tracts, 
resulting in higher rates of cerulean warbler nest predation by jays, 
crows, raccoons, opossums, and snakes. They also cite existing 
regulations and guidelines as inadequate mechanisms for protecting 
cerulean warbler breeding and wintering habitats on public and private 
lands. Finally, the petitioners assert that other natural or human-
caused factors affecting the cerulean warbler's continued existence are 
the likely increase in nest parasitism by cowbirds resulting from the 
destruction and fragmentation of forests as well as direct mortality 
resulting from collisions with communication towers.
    Historical data on the distribution and abundance of cerulean 
warblers are scant. However, it is clear from the nineteenth century 
accounts of several prominent naturalists that the cerulean warbler was 
a conspicuous and abundant species throughout the Ohio and Mississippi 
River valleys (Hamel 2000a). Presently, cerulean warblers are much less 
numerous, and they are absent from some areas where they were abundant 
(Hamel 2000a, Smith et al. 1996). However, the species has increased in 
numbers or expanded its range in the northeastern United States (Hamel 
1992; R. Mulvihill, in litt. 3 April 2001), Quebec (Ouellet 1967), and 
Ontario (Eagles 1987, Oliarnyk and Robertson 1996), perhaps in response 
to the maturation of previously harvested forests. McCracken (1993) 
reports that cerulean warbler populations remain fairly stable overall 
in Canada. Current population trends and estimates are derived from 
several sources, such as the Breeding Bird Survey, Breeding Bird 
Census, Breeding Bird Atlas projects, research and monitoring.
    Much of the support provided by the petitioners for the listing of 
cerulean warbler under the Endangered Species Act is based on Breeding 
Bird Survey (BBS) data they cite as an indication of a declining trend 
for this species. While it is clear that the cerulean warbler's range 
has contracted and the overall population has declined, the species 
exists at high densities at various locations in the core of its range, 
populations are increasing in several areas, and new populations have 
been identified. Using a standardized method for extrapolating bird 
populations from BBS data, the total population of cerulean warblers is 
estimated at 214,000 pairs (K. Rosenberg, in litt. 13 June 2002). 
Roughly 70% of this population is concentrated in the North Cumberland 
Plateau and Ohio Hills physiographic areas.
    The adequacy of the BBS as a method to monitor forest birds, such 
as cerulean warblers, has been questioned (Peterjohn et al. 1995, James 
et al. 1996). These concerns focus on changes in habitat along roadside 
routes, which would reduce the detectability of the birds potentially 
more than their numbers. This is because habitat loss due to 
development tends to be focused along roadsides, thus areas with 
habitat lost to development likely will be over-sampled by BBS surveys, 
with the resulting data possibly overstating the actual decline of the 
cerulean warbler throughout its range. Furthermore, because BBS routes 
are always located along roadsides, BBS coverage may not adequately 
sample those forested habitats that frequently are more distant from 
roads, such as the bottomlands and ridgetops that are preferred by 
cerulean warblers (Hamel 2000a, 2000b). This criticism of BBS suggests 
that other census techniques might be developed that could be more 
effective for detecting cerulean warblers. For example, recent surveys 
conducted by canoe on rivers in Missouri have revealed several 
previously unknown cerulean warbler populations (Robbins 2001); however 
this method would be difficult to implement on a larger scale. In 
addition, there are several logistical concerns about the BBS, which 
arise from the nature of BBS as a volunteer program. Some biologists 
believe that another problem with BBS data for cerulean warblers is the 
potential for unfamiliarity with the song of this species among BBS 
observers (Hamel 2000a).
    We and our colleagues who oversee and analyze BBS data believe that 
BBS data are of questionable value for reliably determining trends for 
making listing determinations even for declining mature forest 
associated species, like the cerulean warbler. For example, BBS routes 
in eastern Kentucky and West Virginia, particularly in the more remote 
parts of those States where cerulean warblers are numerous e.g., in 
West Virginia, cerulean warblers were reported from 74 percent of the 
sites surveyed during the Cerulean Warbler Atlas Project, Rosenberg et 
al. 2000), were not uniformly covered throughout the period of the BBS; 
therefore, trend calculations cannot effectively utilize the data from 
some of these routes (Hamel 2000a). The net effect of these differences 
in coverage is to introduce an unknown amount of uncertainty into the 
BBS trend estimates, particularly in some of the areas central to the 
cerulean warbler's breeding range (Hamel 2000a). Moreover, Sauer (1993) 
indicated that, while sufficient sampling intensity in the BBS existed 
to detect a 50 percent

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decline in population of the species over a 25-year period with a 
probability of 0.9, low relative abundance of this species mandated 
caution when interpreting trend results.
    The BBS estimate of the cerulean warbler's average annual 
population trend (for the period 1966 to 1996) of -3.7 percent per year 
(95 percent confidence interval -2.5 to -5.0) is based on 236 survey 
routes. The average annual trend for the survey period 1966 to 1979 (-
5.5 percent per year, n = 113) indicates a significant decline in the 
cerulean warbler population over the first half of the survey period. 
However, the trend estimate for the remainder of the survey period, 
1980 to 1996 (-0.4 percent per year, n = 183), is not significantly 
different from a stable population. These trend estimates suggest that 
the population declined most dramatically prior to 1980, and may not 
have declined since then. Whether this represents the primary or sole 
period of decline or perhaps indicates that, by 1980, populations were 
reduced to the point that the BBS became a less useful monitoring tool 
rangewide, is not clear (Hamel 2000b).
    Hamel (2000a) stated that land use changes brought about by 
increasing human populations in the breeding, migratory, and winter 
range of cerulean warbler are the underlying causes of the population 
decline of the bird in this century. According to Hamel (2000a), 
Robbins et al. (1992a) compiled the most extensive listing of potential 
threats facing cerulean warblers. This list included six items which 
they categorized as constraints on the breeding grounds as well as non-
breeding season constraints: (1) Loss of mature deciduous forest, 
especially along stream valleys; (2) fragmentation and increasing 
isolation of remaining mature deciduous forest; (3) change to shorter 
(timber harvest) rotation periods and even-aged management, so that 
less deciduous forest habitat reaches maturity; (4) loss of key tree 
species, especially oaks from oak wilt and gypsy moths, sycamores from 
a fungus, elms from Dutch elm disease, and American chestnuts from 
chestnut blight; (5) nest parasitism by the brown-headed cowbird; and 
(6) environmental degradation from acid rain and stream pollution. 
However, research is needed to determine whether these potential 
threats affect cerulean warbler populations, and if so, whether the 
effects of these potential threats vary across the species' breeding 
and winter range.
    We agree with the petitioner's contention that there appear to be 
several potential threats to cerulean warbler migratory, breeding, and 
wintering habitats. Demographic data, and especially recruitment data, 
are currently lacking across the cerulean warbler's range, making it 
impossible to determine the important features of habitat that provide 
for successful reproduction, thus complicating the evaluation of 
potential threats to that habitat. We believe there are significant 
gaps in the threats data currently available to us, including: the 
degree to which timber management and harvest on privately owned forest 
habitat constitute a benefit or threat to the species; loss of habitat 
due to development has not been quantified or analyzed across the 
species' range; mountaintop mining impacts assessments and modeling 
effects on individual species, including the cerulean warbler, are 
currently unavailable; the magnitude of wintering habitat loss and its 
role in the species' decline; and mortality factors during migration.
    We have reviewed the petition, supporting documentation, and other 
information available in our files. On the basis of the best scientific 
and commercial information, we find that substantial information exists 
indicating that listing the cerulean warbler as threatened may be 
warranted. When we make a 90-day finding that listing may be warranted, 
we are required to initiate a review of the status of the species. 
Following the status review we will issue a 12-month petition finding 
as required by section 4(b)(3)(B) of the Act. The 12-month finding 
considers all additional data received during the status review and 
determines whether listing is warranted. If the 12-month finding is 
``warranted,'' we elevate the species to candidate status and assign it 
a listing priority number. We will then commence work on a proposal to 
list the species in the order dictated by its listing priority number 
and the listing priority numbers of other candidate species.
    The petitioners also requested that critical habitat be designated 
for the cerulean warbler. We always consider the need for critical 
habitat designation when listing species. If the 12-month finding 
determines that listing the cerulean warbler is warranted, then the 
designation of critical habitat will be addressed in the subsequent 
proposed rule.

Public Information Solicited

    When we make a finding that substantial information exists to 
indicate that listing a species may be warranted, we are required to 
promptly commence a review of the status of the species involved, 
including providing an opportunity for data and other information to be 
provided by the public for our consideration. A rangewide status 
assessment of cerulean warbler was completed in April 2000, and this 
status assessment is available on the Service's Web site at http://
midwest.fws.gov/endangered/lists/concern.html#Birds. This status 
assessment reviewed most of the information available at that time, so 
we are primarily interested in receiving data on the species that have 
become available since April 2000. We request any additional 
information, comments, and suggestions from the public, other concerned 
governmental agencies, the scientific community, industry, or any other 
interested parties concerning the status of the cerulean warbler. Of 
particular interest is information pertaining to the factors the 
Service uses to determine if a species is threatened or endangered: (1) 
The present or threatened destruction, modification, or curtailment of 
its habitat or range; (2) overutilization for commercial, recreational, 
scientific, or educational purposes; (3) disease or predation; (4) the 
inadequacy of existing regulatory mechanisms; and (5) other natural or 
manmade factors affecting its continued existence.
    If you wish to comment or provide data for our consideration, you 
may submit your comments and materials to the Field Supervisor, 
Ecological Services Field Office, U.S. Fish and Wildlife Service, 608 
East Cherry Street, Room 200, Columbia, Missouri 65201. Our practice is 
to make comments, including names and home addresses of respondents, 
available for public review. Respondents may request that we withhold 
their home address, which we will honor to the extent allowable by law. 
If you wish us to withhold your name or address, you must state this 
request prominently at the beginning of your comment and explain the 
reason for your request. However, we will not consider anonymous 
comments. To the extent consistent with applicable law, we will make 
all submissions from organizations or businesses, and from individuals 
identifying themselves as representatives or officials of organizations 
or businesses, available for public inspection in their entirety. 
Comments and materials received will be available for public 
inspection, by appointment, during normal business hours at the above 

References Cited

    You may request a list of all references cited in this document, as

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well as others, from the Columbia, Missouri Field Office (see 


    The primary author of this document is Amy Salveter, Columbia, 
Missouri Field Office (see ADDRESSES).


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

    Dated: September 24, 2002.
Steve Williams,
Director, Fish and Wildlife Service.
[FR Doc. 02-27004 Filed 10-22-02; 8:45 am]