One of America’s Rarest Butterflies Finally Receives Protection under the Endangered Species Act


Media Contacts:

Scott Hoffman Black, Executive Director, The Xerces Society for Invertebrate Conservation

(503) 449-3792 |


For immediate release

OLYMPIA, Wash.; April 11, 2018—More than 15 years after the Xerces Society for Invertebrate Conservation initially submitted a petition asking for federal protection for the island marble, the U.S. Fish and Wildlife Service (USFWS) announced today that the butterfly warrants protection as an endangered species under the Endangered Species Act.

The island marble is among the most imperiled animals in the world. Fewer than 200 adults were observed during surveys in 2017 and its habitat faces continued threats.

“We are happy that the U.S. Fish and Wildlife Service has taken this positive step to protect this butterfly under the Endangered Species Act,” said Scott Hoffman Black, Executive Director of the Xerces Society. “After years of delay, the Service must move quickly to implement conservation measures to reverse declines.”

The butterfly is named for the beautiful green and white marbling on the underside of its wings and because it lives on islands. It has already been extirpated from Vancouver and Gabriola Islands in British Columbia and from Lopez Island in Washington State, and now is only found on San Juan Island in Washington State.

The Xerces Society petitioned the USFWS asking for Endangered Species Act protection twice. The first time in 2002, with the Center for Biological Diversity, Friends of the San Juans and the Northwest Ecosystem Alliance. The USFWS did not list the species.

The Xerces Society petitioned the USFWS again in 2012. That resulted in a 2016 decision by the USFWS that listing of the island marble butterfly was warranted but precluded by higher priority listing actions.

“The island marble’s extremely small population size, isolation and restricted distribution place a huge question mark over its survival,” said Sarina Jepsen, Endangered Species Program Director with the Xerces Society. “Endangered Species Act protection is this butterfly’s only real hope.”




For photos, please contact Matthew Shepherd at

For more information about the island marble butterfly visit:

To read the complete Endangered Species Act petition submitted to the U.S. Fish and Wildlife Service visit:

The Federal Register entry, Endangered and Threatened Species: Endangered Status for the Island Marble Butterfly and Designation of Critical Habitat, can be accessed at