Safe passage for butterflies
The lonely Mission Blues of Twin Peaks aren’t the only butterflies that are essentially living on an island in a sea of city. The Green Hairstreak butterfly, a dashing, shimmery green, nickel-sized insect, now lives in just three parks in San Francisco. It’s a grassland butterfly; it would have flown from hilltop to hilltop before concrete blocked its path.
Hawk Hill, one end of the Green Hairstreak corridor.
The road from Hawk Hill. Where's a Hairstreak to go?
Local lepidopterist Liam O’Brien decided to do something about it, and last weekend I joined his tour of the Green Hairstreak Corridor. Working with non-profit Nature in the City, and with people who–many of them unwittingly–share a neighborhood with the butterflies, he’s planted the native plants the Green Hairstreak caterpillars eat along sidewalks and in medians. He’s trying to link two of the remaining populations, giving them a better shot at survival.
A corner volunteers have adopted. They planted the right plants, and the hairstreaks followed.
Green Hairstreak larvae only eat two plants: deer brush and coastal buckwheat.
The tour heads up the rocky outcrop at the other end of the corridor
O’Brien says San Francisco is most well known as the county that lost a butterfly: the Xerces Blue, a San Francisco native, was the first butterfly to go extinct in the U.S. because of urban development. He says he doesn’t know if this project will work, but that he just wants to try.
O'Brien holds a picture of the Xerces Blue.
Nature in the City leads other tours of local habitats. And check out their map of the Green Hairstreak corridor.
And…you probably noticed there are no pictures of the butterflies themselves here. I can’t claim to be much of a wildlife photographer. Nature in the City has nice pictures on their site, though.
