Pacific Southwest Region
California, Nevada and Klamath Basin

Hermes Copper Butterfly Added as a Candidate for Endangered Species Act Protection

Apr 13, 2011

April 13, 2011

Contact: Stephanie Weagley, U.S. Fish and Wildlife Service (760) 431-9440 ext. 210

Hermes Copper Butterfly Added as a Candidate for Endangered Species Act Protection

CARLSBAD, Calif. -- The U.S. Fish and Wildlife Service (Service) announced today Hermes copper butterfly (Hermelycaena [Lycaena] hermes) warrants protection under the Endangered Species Act, but a proposal to list the species is precluded by other higher priority species actions. The butterfly will be added to the list of candidates for Endangered Species Act protection, where its status will be reviewed annually until either a proposal to list the species as endangered or threatened is undertaken, or a change in status is warranted.

The Service’s determination, known as a 12-month finding, was made after an in-depth status review was conducted involving the best available scientific and commercial information. We found that Hermes copper butterfly is primarily threatened by large (“mega”) wildfires and the effects of small population size and isolation, and to a lesser extent, habitat loss due to increased wildfire frequency and habitat fragmentation.

Species population loss due to wildfires combined with isolation and small existing population size makes Hermes copper butterfly vulnerable to extinction or likely to become endangered within the foreseeable future throughout all or a significant portion of its range.

The historical range of Hermes copper butterfly is limited to San Diego County, California, south to Santo Tomas, in Baja California Norte, Mexico. Today, the butterfly is known to occur primarily in the southwest portion of San Diego County. It has been documented in Mexico, but its distribution is not well-known. Approximately 49 percent of all known historical populations are believed to have been extirpated. 

The effect of past habitat fragmentation is considered irreversible and has continuing impacts over the range of the species. Additionally, the threat of wildfire continues to exist throughout the species range; however, the impact of wildfire on the butterfly and its habitat occurs on a sporadic versus a daily basis and we do not have the ability to predict such events. While the Service’s evaluation finds these effects serious, they are not imminent.
As a result, the Service’s competing demands on limited resources must be devoted to listing actions for species facing greater risks. We assigned Hermes copper butterfly a listing priority number of 5, out of a 1 to 12 range. The lower the listing priority number, the higher the listing priority for a species.

While candidate species do not receive statutory protection under the Endangered Species Act (Act), annual reviews and identification of candidate species provides the Service and other Federal agencies, states, tribes, and other partners with notice that a species is in need of conservation, allowing them to address threats before they require protection under the Act.

Although a significant amount of butterfly habitat has been lost due to previous urban development within San Diego County, the remaining areas believed to be currently occupied (approximately 66 percent) are protected from destruction by development due to their presence on federally owned lands or lands protected under the San Diego County Multiple Species Conservation Program and several of its subarea habitat conservation plans.

We anticipate current management efforts will continue with our conservation partners and we will continue to actively engage the public and others in the search for improved and innovative ways to conserve and protect species and their habitats. 

Hermes copper butterfly is a small, brightly-colored, and relatively sedentary butterfly that inhabits coastal sage scrub and southern mixed chaparral and lays its eggs only on the larval host plant, spiny redberry. Adults feed almost exclusively on nectar from California buckwheat.

In 2004, the Service received a petition from the Center for Biological Diversity and David Hogan to list the butterfly and determined in a 2006 finding that the petition did not present substantial scientific information indicating listing the butterfly may be warranted. A settlement agreement was reached in October 2009, whereby we agreed to review the petition again and look at any new information about the butterfly and its habitat that has since become available. On May 4, 2010, the Service determined listing Hermes copper butterfly may be warranted.

A copy of the 12-month finding can be viewed online today at the Federal Register Public Inspection Page. The official copy will be published on April 14, 2011, and will be posted on Look for the box that reads “Enter Keyword or ID” and enter the Docket number, which is FWS-R8-ES-2010-0031.

New information, materials, comments, or questions concerning this finding can be submitted to or to Field Supervisor, Carlsbad Fish and Wildlife Office, 6010 Hidden Valley Road, Suite 101, Carlsbad, CA, 92011. A photo of the butterfly can be found on Flickr.

The mission of the U.S. Fish and Wildlife Service is working with others to conserve, protect and enhance fish, wildlife, plants and their habitats for the continuing benefit of the American people. We are both a leader and trusted partner in fish and wildlife conservation, known for our scientific excellence, stewardship of lands and natural resources, dedicated professionals and commitment to public service. For more information on our work and the people who make it happen, visit

-- FWS --