Photo of Barbara Kobayashi by Troy Dean

Photo of Barbara Kobayashi by Troy Dean

Photo by Taji Allen, Cloud Candy Photography

Photo by Taji Allen, Cloud Candy Photography

Connecting islands in the sky to save an imperiled butterfly.

Barbara Kobayashi, Mike Belcher, Jeff Brown with Kids in Parks and Hoover Middle School students, Bob Hall, Ellen Papp, Joan and Jack Louie, Mike Ng and so many others care for 14+ butterfly habitat gardens in the Green Hairstreak Corridor. In addition to this, San Francisco State University students, supervised by Barbara Holzman, PhD, conduct research on the success of the Corridor.

In early spring, female Green Hairstreak butterflies (Callophrys viridis) mate and disperse looking for host plants to expand their population. This iridescent green nickel-sized butterfly can only fly a few hundred feet from her original habitat. In the Inner Sunset District of San Francisco, there are three distinct hilltop populations surrounded by neighborhoods. Because the populations are small and isolated, the butterflies would vanish without intervention. 

In 2006, the Green Hairstreak Corridor was initiated by lepidopterist Liam O'Brien and continues to be managed by Nature in the City. The corridor connects these populations to each other with strategically placed Street Parks planted with the Hairstreak’s habitat, and cared for by neighborhood residents and schoolchildren. Every year, since inception, the population of butterflies and other associated insects and birds, has been increasing two-fold.

Photo of San Francisco State University students by Liam O'Brien

Until I moved to San Francisco to pursue my education, I never appreciated the vastness, the serenity, and its undeveloped charm.

It was a rough transition, but then I discovered the Green Hairstreak Corridor Project. I related more to a green nickel-sized butterfly better than any of my peers. I had a epiphany while volunteering for this project: “The green hairstreak butterfly is just like me! It has been transitioning through the last century of urban development.” Ever since then, I’ve dedicated my last three semesters of college in assisting the project any way possible. I have performed vegetation cover analyses, conducted population surveys, compared populations between restored habitats and natural habitats, compared past population data with current data, created plant identification cards for native plants found within the corridor, and many other small tasks.

The Green Hairstreak Corridor Project has given me so much clarity to what I want to do for my future. I want to pursue a career in urban environmental restoration. I have learned about urban ecology, stewardship, and the importance of community involvement.
— Adriana Austin, San Francisco State University

This brochure and self-guided tour celebrates the restored habitats in the Green Hairstreak Corridor. You can also click here for a browsable Google Map of the Corridor. 

Click here to view Corridor brochure

Included is our beneficial plant list for the project.  Use this guide to create habitat in your yard or neighborhood garden, and help encourage these butterflies to continue proliferating.

Click here to view our plant list