Center for Biological Diversity

For Immediate Release, January 7, 2020


Tara Cornelisse, (971) 717-6425,

Rare Southern California Butterfly Proposed for Protection as Threatened Species Under Endangered Species Act

SAN DIEGO, Calif.— After 28 years of petitions and lawsuits by the Center for Biological Diversity, the U.S. Fish and Wildlife Service today finally proposed protecting one of Southern California’s rarest butterflies, the Hermes copper butterfly, as a threatened species.

The agency also proposed designation of 35,000 acres of protected critical habitat in San Diego County. Both proposals are required to be finalized in one year following public comment period.

“Californians love their native butterflies, and it’s important to protect San Diego County’s remaining islands of habitat for this rare butterfly,” said Tara Cornelisse, a scientist at the Center who specializes in arthropods. “The decline of the Hermes copper has mirrored the destruction of Southern California’s native ecosystems. Urban sprawl, rampant wildfires and climate change are a triple threat to this beautiful butterfly, which desperately needs Endangered Species Act protection.”

The Hermes copper inhabits coastal sage scrub and chaparral habitats only in San Diego County and northern Baja. Its survival depends on dwindling patches of its host plant, the spiny redberry. This small, bright yellow-orange, spotted butterfly is jeopardized by urban development, increasingly frequent and severe wildfires, and climate change.

The Hermes copper occupied many San Diego coastal areas prior to urbanization, and still persists in some foothill and mountain areas up to 45 miles from the ocean. The butterfly had declined from at least 57 historical populations to only 17 by 2011. Devastating wildfires have increasingly burned through key Hermes copper habitat, putting an end to the tenuous existence of many remaining butterfly populations.


Even as the Hermes copper enchanted early California butterfly enthusiast John A. Comstock, who described it in 1927 as “a fascinating little sprite,” the insect was endangered by increasing urban development. By 1980 staff at the San Diego Natural History Museum noted that San Diego’s rapid urban growth put the future of the butterfly in the hands of developers. The Fish and Wildlife Service first identified the butterfly as a potential candidate for Endangered Species Act protection in 1984.

The Center for Biological Diversity and San Diego Biodiversity Project filed formal petitions in 1991 and 2004 to protect the species. A lawsuit was required to force the Service to respond to the second petition, but the agency announced in 2006 that it would not protect the species, despite fires in 2003 that burned nearly 40% of the butterfly’s habitat. The Center filed a second lawsuit in 2009, but the Service again denied protection by placing the butterfly back on the candidate list in 2011. The Center sued a third time in May 2019, which forced the Service to make today’s proposed listing rule.

The Trump administration has only protected 21 species under the Endangered Species Act — the lowest of any administration at this point in its presidential term. By comparison, during the Obama administration, 360 species were protected under the Endangered Species Act. Under Clinton 523 species were protected, while 232 species were protected under George H.W. Bush, 62 species under George W. Bush, and 254 under Reagan.


The Center for Biological Diversity is a national, nonprofit conservation organization with more than 1.6 million members and online activists dedicated to the protection of endangered species and wild places.

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