Daily Archives: April 8, 2010

San Diego Butterfly Earns New Chance at Endangered Species Protection

For Immediate Release, April 5, 2010

Contact: Jonathan Evans, Center for Biological Diversity, (415) 436-9682 x 318
David Hogan (author of listing petitions), (760) 809-9244

San Diego Butterfly Earns New Chance at Endangered Species Protection

SAN DIEGO, Calif.— Due to a lawsuit by the Center for Biological Diversity, today the U.S. Fish and Wildlife Service announced that one of Southern California’s rarest butterflies, the Thorne’s hairstreak, warrants consideration as an endangered species. Imperiled by its limited range, the Thorne’s hairstreak butterfly exists in only one small area of Tecate cypress trees on Otay Mountain in San Diego County.

“Protection of this imperiled butterfly demonstrates that science must trump politics in wildlife protection,” said Jonathan Evans, staff attorney with the Center for Biological Diversity. “Listing under the Endangered Species Act will prompt recovery planning and efforts to bring this butterfly back from the brink of extinction.”

The remaining populations of the Thorne’s hairstreak are located inside the U.S. Bureau of Land Management’s Otay Mountain Wilderness. However, Otay Mountain’s native plant and animal communities have suffered from dozens of wildfires. During the 2003 Mine fire, roughly 68 percent of Thorne’s hairstreak habitat was lost.

Conservation groups have sought protection for the threatened butterfly for almost 20 years. First in 1991 and again in 2004, the San Diego Biodiversity Project and the Center for Biological Diversity, respectively, filed formal petitions with the federal government to protect the species.

Today’s decision was part of a legal settlement between the Center for Biological Diversity and the Fish and Wildlife Service resulting from the Bush administration’s interference with agency science — which led to a previous agency decision not to consider the Thorne’s hairstreak for federal protection. Documents revealed that political inference had reversed the course of agency biologists, who had actually recommended further research into protection of the butterfly under the Endangered Species Act.

“Past wildfires in San Diego county show that we could lose these beautiful creatures in one strong blaze,” said David Hogan, author of both scientific petitions to gain protection for the butterfly under the Endangered Species Act. “Endangered Species Act protection provides a crucial safety net to protect these butterflies for future generations.”

The Fish and Wildlife Service is soliciting comments on protection for the Thorne’s hairstreak butterfly for 60 days.

Background: The Thorne’s hairstreak butterfly

The Thorne’s hairstreak is a delicate butterfly with wings that range from reddish brown to mahogany brown with lavender overscaling. This butterfly has an extremely limited geographic range, existing in only one small area on Otay Mountain in San Diego County. This limited range is due, in part, to the limited distribution of its host plant, the Tecate cypress, upon which it depends.

The Thorne’s hairstreak has been recognized as unique and imperiled for more than 20 years. Unfortunately, the status of the Thorne’s hairstreak butterfly continues to deteriorate due to the increased threat of wildfire posed by an increasing human population and illegal migration across the Mexico border. Because of its limited distribution, one wildfire event could wipe the species off the planet. In fact, the 2003 wildfire event reduced the Thorne’s hairstreak occupied locations by half, from 10 to five. Prior to the 2003 wildfires, biologists estimated that about 400 Thorne’s hairstreak butterflies remained in about eight populations. After the fire, surveys turned up fewer than 100 individual butterflies in four to five locations.


The Center for Biological Diversity is a national, nonprofit conservation organization with more than 255,000 members and online activists dedicated to the protection of endangered species and wild places.

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