Citing new genetic evidence that the coastal California gnatcatcher is not a distinct subspecies as previously claimed, but is part of a single, healthy and abundant species that ranges from Southern California to the southern tip of Baja, Mexico, the National Association of Home Builders and several other parties filed a petition to remove the coastal California gnatcatcher from the list of threatened species. The petition to the U.S. Fish and Wildlife Service (Service) is based on a peer-reviewed study of gnatcatcher DNA by Dr. Robert Zink of the University of Minnesota and several other scientists.
The study, published in the ornithological journal The Auk confirms prior published genetic studies of gnatcatcher DNA by Dr. Zink and other nationally-recognized scientists. The new study concludes that gnatcatchers in California are not genetically distinct from the abundant populations of gnatcatchers south of the border. The new DNA evidence is the information that the Fish and Wildlife Service previously suggested would warrant removing the gnatcatcher from the ESA list.
The gnatcatcher is a common blue-gray bird in Mexico and southern California. The Fish and Wildlife Service listed the gnatcatchers in 1993 as a threatened “subspecies” whose range is limited to southern California and northern Baja, Mexico. The listing triggered a firestorm of controversy and led to restrictions on land use across southern California. Approximately 197,303 acres in San Diego, Orange, Riverside, San Bernardino, Los Angeles, and Ventura Counties have been designated as critical habitat for the coastal California gnatcatcher. Federal officials estimate that the economic impact of these restrictions will total more $900 million by year 2025.
At the time of the listing, several scientists testified that genetic studies should be conducted to determine whether the gnatcatcher qualified as a subspecies. The Service disclaimed the need for genetic studies and instead relied on measurements of physical characteristics such as the degree of brightness of feathers to conclude that the gnatcatchers in southern California were distinct from the abundant populations in Mexico. In 1994, the District Court for the District of Columbia invalidated the gnatcatcher listing because the Service failed to disclose information relied upon in the listing. Endangered Species Committee v. Babbitt, 852 F.Supp.32 (D.D.C. 1994). The Service relisted the gnatcatcher in 1995.
In 2000, the Journal of Conservation Biology published a study of gnatcatcher mitochondrial DNA by Dr. Zink and Dr. Jonathan Atwood (the petitioner for the listing). The study concluded that there is no distinct subspecies of gnatcatcher. Citing the need for analysis of nuclear DNA in addition to mitochondrial DNA in 2010 the Service denied a petition to de-list the gnatcatcher.
The new petition analyzes the nuclear DNA of gnatcatchers throughout its range. The Zink et. al. study confirms that the California gnatcatcher is not a separate subspecies and does not exhibit ecological distinctiveness.
Nossaman LLP and the Pacific Legal Foundation filed the petition. Nossaman represents the National Association of Home Builders and the California Building Industry Association in the petition proceeding.