Last week the U.S. Fish and Wildlife announced its decision not to list the Cerulean Warbler under the Endangered Species Act. The decision was in response to a petition, in 2000, to list the small songbird as a threatened species. (This petition was filed by a coalition of conservation groups, including the National Audubon Society.) In 2002, the FWS announced that the petition had sufficient merit to begin a status review. Since then, the agency has missed several deadlines, and made last week's announcement in response to a suit brought by the conservation groups in February 2006.
The Fish and Wildlife Service explains its reasoning [1] as follows:
Although there is no precise estimate of the current abundance of the cerulean warbler, the Service used a 1995 population estimate of 560,000 warblers during its review of the species’ status. Based on 40 years of data obtained through the Breeding Bird Survey which indicates the population is declining at about 3 percent each year, the estimated population in 2006 would be approximately 400,000. At this rate of decline, the Service estimates the cerulean warbler population would number in the tens of thousands 100 years from now.
This analysis assumes that the rate of decline will remain constant. However, there is already evidence that the rate of decline is increasing in core areas of the Cerulean Warbler's range. Given land-use changes, that decline may worsen. A statement by the National Audubon Society [2] cites research from the past six years:
“The birding community is greatly concerned because the Cerulean has been declining throughout its range for such a long period of time,” said Greg Butcher, Ph.D., Director of Bird Conservation with Audubon. He said the bird has declined an average of 6 percent per year over the last eight years, compared to an annual average of 4.3 percent from 1966 to 2004....
Since the petition was filed, new information has come to light about the increasing loss and fragmentation of the Cerulean’s eastern forest habitat from mountaintop removal mining. This form of surface mining is expected to increase dramatically in the core of the Cerulean’s range where the bird has already suffered drastic population declines – 80 percent in the Cumberland Plateau in Tennessee, Kentucky and West Virginia, and 65 percent in the Ohio Hills in Ohio, West Virginia and Pennsylvania.
A multi-agency environmental study of mountaintop mining in four states (WV, TN, KY, VA) found that between 1992 and 2012, some 1.4 million acres of forests will be lost, more than half due to mountaintop mining.... Ceruleans will be the most affected because they favor the steep slopes and ridge tops targeted by mountaintop removal. More than 70 percent of breeding Cerulean Warblers are found in the Ohio Hills and Cumberland Plateau regions targeted by mountaintop mining.
Listing under the Endangered Species Act would have required federal and state agencies to create a recovery plan for the songbird, and put legal muscle behind conservation efforts. For now, stabilizing the Cerulean Warbler population will depend on private efforts and voluntary initiatives by government agencies within the warbler's core range.
The Cerulean Warbler's winter habitat is as vital to its survival as its breeding habitat. To that end, individuals can help by supporting shade-grown coffee plantations, where possible. For more on the link, see the explanations provided by Audubon at Home [3] and Coffee and Conservation [4].