10 April 2014
THE SHORT ANSWER
Xerces Blue (Glaucopsyche xerces) was a species of butterfly. It has the sad distinction of being one of the first American butterfly species to become extinct in modern times.
Sporting blue wings with white spots, it was first documented and described in 1852. The last sightings of this butterfly were in the early 1940’s in the Golden Gate National Recreation Area. Extensive human settlement in the Bay Area, around San Francisco, California, resulted in a swift loss of habitat. The sudden disappearance of the butterfly’s familiar range is thought to have caused its extinction.
Efforts are underway to introduce the Palos Verdes Blue butterfly into the northern California range of the extinct Xerces Blue. Indigenous to the Los Angeles area, the Palos Verdes Blue is a cousin of the Xerces.
The Xerces Blue butterfly has gained a measure of fame, in part, because of its extinct status, but also because its name was adopted by a non-profit conservation organization. The Xerces Society focuses its efforts on the preservation of local California habitat for the benefit endangered species, native pollinators, and the maintenance of watershed health.