Green Hairstreak Corridor

The Coastal Green Hairstreak butterfly (Callophrys viridis) was thought to be extinct in San Francisco due to habitat loss and invasive plants. The species was rediscovered in San Francisco's Golden Gate Heights neighborhood in April 2006 by lepidopterist, Liam O’Brien.

Nature in the City and our partners are restoring living “stepping-stones” to connect larger butterfly habitats. The Green Hairstreak Corridor is supporting the recovery of a species.

The corridor includes natural areas, street parks and school gardens, all stewarded by local neighborhood residents and students. With nearly 20 established habitat sites so far, you can find this butterfly on coastal dunes, rocky outcrops, and in front and backyards throughout the corridor.

San Francisco State University researchers annually monitor the expansion of plants and butterflies at each site. We know that a single butterfly lives for about two weeks and flies up to 300 feet from its original habitat. Also, we know that Green Hairstreak butterflies emerge as adults from early-February to late-May, peaking in mid-April.

There is so much yet to be discovered year-round in the corridor. Your iNaturalist observations help us gather critical data about what’s living in the corridor: pollinators, moths, plants, birds, amphibians, insects and more. Your data helps us effectively restore this true urban wildlife corridor. less ↑