EHL is seeking listing under the California Endangered Species Act for the rare Quino checkerspot butterfly.

In view of ongoing decline and threats, the Center for Biological Diversity (CBD) and EHL filed the petition to list the butterfly in December 2024. This updates an earlier version, submitted in 2020, which had been stalled by legal uncertainty over whether insects could be listed under CESA. This is now favorably resolved.

Once widespread in Southern California south of Ventura, habitat fragmentation has extirpated the animal from Orange, San Bernardino, and Los Angeles Counties. Even though its host plants – needed by the caterpillars – remain in those places, populations collapsed. In Riverside County, the butterfly’s territory continues to shrink due to rural subdivision, yet the Multiple Species Habitat Conservation Plan does not have enough money to acquire these properties. Also, wildfires are replacing host plants with non-native weeds, in which the butterfly cannot survive. In San Diego, the Quino faces major threats from a proposed landfill and other development. 

The Quino checkerspot is already federally listed, but this has not been enough to control the threats and stop decline. The higher standards for conservation under CESA would be a big help.

EHL assisted CBD’s staff scientists with research for the well-documented petition, which is available here.