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Species of Concern

Cerulean Warbler 90-Day Petition Finding
Questions and Answers


cerulean warbler


1. What is the cerulean warbler?
The cerulean warbler is a small, migratory bird that is named for the blue color of the male. It eats mostly insects and feeds in the mid and upper branches of tall trees. The cerulean is found in woodlands of the eastern United States, both in uplands, wetlands, and on mountainsides - but always associated with mature forests with canopy gaps and complex canopy structure, and often with very large, tall trees.


2. Why are we concerned about the cerulean warbler?

The cerulean warbler population has apparently declined. However, we do not have reliable population monitoring data across its range so its population status and recent population trend are not clear. Based on data from portions of its range, we do know that cerulean numbers and range have increased in some areas and declined in others. Additionally, current threats to its habitat within the heart of its breeding range have brought concern for the cerulean to the forefront.

Overarching the concerns for cerulean warblers because of population declines and habitat threats is that the fact that there is much that we do not know about this bird.


3. What are the threats to the cerulean warbler?
Cerulean warblers breed in the eastern U.S. and Canada, then migrate to and winter in South America. All the habitats ceruleans use throughout the year (i.e., breeding, migratory, and wintering habitats) are threatened by loss and degradation.


Across the species' historical breeding range, vast acreages of forest have been cleared and replaced with cities, suburbs, farms, and roads. Remaining forests are often fragmented into small tracts that are not suitable nesting sites for ceruleans. Larger tracts of forests in the eastern U.S. may not be managed to provide the interspersion of large trees and openings that are believed to create suitable nesting habitat. Additionally, mountaintop removal mining, a method of mining coal by removing the tops of mountains and placing the overburden in stream valleys, has the potential to destroy large acreages of suitable breeding habitat. Unfortunately, the area of the country with the highest density of ceruleans is also in a coal-mining region where mountaintop removal mining is practiced.


We know little about the migratory habitat needs of ceruleans as they fly to and from the U.S. and South America. We do know that much of the forest along the migration route has been cleared. We also know that as they migrate back and forth across the Gulf of Mexico they frequently encounter strong winds and storms and thus need cover for resting soon after they arrive on land. Many woodlots near the coasts have been lost due to development and coastal erosion, so many former resting areas may no longer exist.


Cerulean warblers have been observed in the canopy and along the edges of broad-leaved, evergreen forests and woodlands at middle and lower elevations on the east slopes of the Andes Mountains from Columbia to Peru, and Venezuela. These areas are being converted from native forest to pastures and farms.

Petition Information

4. Why are we publishing a 90-day finding?

Under the ESA, anyone can petition the Service to list a species and revise critical habitat. The 90-day finding is the first step in processing a petition. The Service received a petition to list the cerulean warbler on October 31, 2000. The petition, which was sent by the Southern Environmental Law Center, was signed by 28 various organizations. The petition asked the Service to list the cerulean warbler as threatened and to designate critical habitat. The petitioners contend that the most immediate threat to the species is the loss of habitat, including fragmentation of its woodland breeding habitat due to logging, lack of mature forests and floodplain forests, and loss of winter habitat in South America. The petition noted a rangewide decline of cerulean warbler populations of about 70 percent since 1966.


5. We received the petition in late 2000; why are we processing it now?

The petition was received on October 31, 2000. Because of funding shortfalls, the Service was unable to process listing petitions at that time. The petitioners received notice that the Service could not address the petition at that time and informing them that we were already reviewing a status assessment contracted by the Service and completed in April 2000 by Paul Hamel, U.S. Forest Service. The assessment concluded that although populations of the cerulean warbler are declining, the species was not in danger of extinction at that time. The Service received a notice of intent to sue in March 2001 for failing to meet the 90-day finding deadline. In late 2001, the Service provided the petitioners with information about its review of the cerulean warbler's status and the decision that it would not be elevated to candidate status. Subsequently the petitions provided a second NOI to sue. In mid-2002, Region 3 determined that there were sufficient fiscal year ‘02 listing funds remaining to address the petition, and the petitioners were notified that the Service would review the petition.


6. Does the 90-day finding constitute a final decision to list the cerulean warbler?

No, the 90-day finding is not a decision to list the cerulean warbler. The 90-finding is the Service's first decision on whether the petition provides enough information to be either "substantial" or "not substantial." A non-substantial finding ends the petition process. A "substantial" finding does not mean the listing action is warranted, rather it means that the petitioners have presented substantial information indicating that the requested action may be warranted. If the 90-day petition finding is substantial, the Service begins a formal status review of the species which culminates in a 12-month finding on the petition.


7. What information does the Service use to make a 90-day finding?

The Service examines the information contained in and referenced by the petition, along with other available information it may have, to make the 90-day finding. The Service also contacts States and Tribes within the species' range and requests information from them. Before receiving the petition to list the cerulean warbler, the Service had contracted with Dr. Paul Hamel of the U.S. Forest Service to conduct a status assessment of the cerulean warbler, which was completed in April 2000. Following Hamel's status assessment, but prior to initiating the review of the petition, the Service completed an additional study to examine threats to, and management of, cerulean warbler habitat on public forest lands.

What's Next?

8. What is a 12-month finding?

A "substantial" 90-day finding triggers a status review that culminates in a 12-month finding. The status review includes a public comment period during which the Service tries to obtain all available relevant information on the species' status, trends, and threats. The 12-month finding is based on all available information, including the additional information gathered during the comment period. A 12-month finding is the Service's decision on whether the petitioned action is warranted. The finding may be "warranted," "not warranted," or "warranted but precluded." A warranted finding means that the Service believes the species should be listed and promptly prepares a proposal to list. A not warranted finding means the Service does not have information to support a proposed listing. A warranted but precluded finding means that the Service has sufficient information to propose a listing, but work on preparing a proposal to list is precluded by listing actions for higher priority species. In that case, a listing priority number is assigned to the species based on magnitude and degree of threat, and other factors, and a listing proposal is subsequently prepared after species with higher priority numbers have been addressed..


9. Does the Service have enough information to issue a 12-month finding?

The Service's 12-month finding will be based on the best available information, which includes the April 2000 status assessment, the Service's additional study of habitat loss on public lands, and any additional information the Service receives. We will also open a 90-day public comment period to collect all available information about the cerulean warbler, and to seek input from species experts and other individuals and institutions which may have information or data to share.


10. What are the information gaps that limit our understanding of the biology, life history, and threats to the cerulean warbler?

We do not have adequate monitoring data that can tell us what has happened to the species population, over its entire range, for the last several decades. Valid monitoring information is only available at select sites, usually public lands, where monitoring cerulean warbler numbers has been an ongoing project. Adequate and valid monitoring data are essential to make appropriate decisions under the Endangered Species Act.


We need information on how ceruleans use their breeding habitat in different parts of the range and what habitat components are most important. This information will direct how we manage forests for cerulean warblers. As a result of concerns for survival of cerulean warblers, studies of some aspects of the cerulean's life history requirements were initiated. Data from these studies are being used to develop management recommendations, but additional research is needed to verify the results of those studies and to provide complete life history and habitat use information.


On their wintering grounds and along their migratory routes, few studies have been conducted to determine where ceruleans are found and how they use those habitats. Therefore we do not know how and if changes in land use on these areas has been a factor in their population declines.


11. What conservation activities are currently being undertaken to benefit cerulean warblers?

A number of groups and agencies are monitoring cerulean warblers on their properties. Also, the Cornell University Laboratory conducted the Cerulean Warbler Atlas Project to determine the number of breeding pairs and productivity, describe nesting habitat, and identify potential threats to the population and its habitat.


In addition to the Atlas Project, mentioned above, several other studies are underway to provide information on the life history of cerulean warblers and their habitat requirements, both in breeding and wintering areas. The Service will continue to emphasize and assign high priority to cerulean warbler research and monitoring efforts aimed at gaining a better understanding of threats to the species.


To restore breeding habitat, hardwood trees are being replanted in bottomland areas that had previously been maintained as open fields on National Wildlife Refuges, National Forests, and National Parks throughout the cerulean warbler's breeding range.


State and Federal land management agencies are investigating and implementing ways to conserve and improve cerulean warbler habitat. Several National Forests throughout the cerulean warbler's breeding range have implemented conservation measures for migratory birds, and they are monitoring the effects of various management practices on interior forest breeding birds. Some of these efforts are showing early signs of success in attracting singing males with some evidence of productive breeding efforts, but more research is needed to address persistence and overall reproductive success at these sites.


A consortium of private, State, and Federal natural resource managers and species experts have joined together to develop a collaborative, proactive strategy conserving the cerulean warbler.


12. If the Service ultimately makes a 12-month rule to list cerulean warbler, how will that impact public and private land management practices?

At this time it is too early to know. If a decision is made to list the cerulean warbler, a recovery plan will be developed which will describe best management practices and serve as a guide for Federal land management agencies.


13. How do I get more information, or submit comments for the Service's 12-month finding?

Information on the petition to list the cerulean warbler and the Service's 2000 status assessment is available on the Service's website at The Service is seeking additional information from the public on the cerulean warbler and threats to its habitat. Information and comments may be submitted to Field Supervisor, Ecological Services Field Office, U.S. Fish and Wildlife Service, 608 East Cherry Street, Room 200, Columbia, Missouri 65201. They may also be faxed to that office at 573-876-1914. To ensure their consideration, all comments and other information must be received by the close of the comment period on January 21, 2003.


The Petition Process

Region 3 Guidance for Potential Petitioners


Back to Cerulean Warbler Home Page


Last updated: February 10, 2016