New butterflies introduced in SF's Presidio after species went extinct in 1940s

ByDan Ashley and Tim Didion KGO logo

Friday, April 19, 2024

New butterfly species introduced in SF's Presidio

The new Silvery Blue butterflies in SF's Presidio will replace a long-lost species called the Xerces Blue that went extinct in the 1940s.

SAN FRANCISCO (KGO) -- An intrepid group of butterflies is about to help turn the clock back nearly a century in San Francisco's Presidio. Biologist Durrell Kapan, Ph.D. of the California Academy of Sciences says the butterflies will be replacing a long-lost species called the Xerces Blue that went extinct in the 1940s.

"The Xerces Blue was a beautiful blue butterfly that was restricted to the dune habitat from Fort Funston to Baker Beach, and occasionally was seen on places like Lone Mountain or once or twice on Telegraph Hill," Kapan said.

That was before the west side of San Francisco transformed from sand dunes to development, wiping out their habitat. But ecologist Lew Stringer says the Presidio has spent decades restoring the native dunes around the former Army post -- including butterfly-friendly plants, like the edible deer weed.

"If we didn't have this habitat, we wouldn't have the plant and we wouldn't have the ability to bring back the species that was lost to San Francisco many years ago," Stringer told a crowd of onlookers.

MORE: Here's how trust team is working together to restore Presidio Forest in SF

And with butterflies in tow, the joint team from the Academy of Sciences and the Presidio Trust hit the trail. But they say the scientific part of the journey actually began much earlier, in the sand dunes of Monterey. That's where biologists from the Academy were able to identify the closest living relative to the extinct Blue Xerces. Combining sophisticated genetics with matching samples from their own collection, the results pointed to a species known as the Silvery Blue.

"In fact, we sequenced the complete genome of three different subtypes of the Silvery Blue butterflies, so we could say which one was closer," Kapan said.

And with a delicate touch, wildlife ecologist Phoebe Parker-Shames, Ph.D., helped settle the Presidio's newest residents into their adopted home, placing them underneath a protective net to let them get acclimated. And even giving them a quick drop of Gatorade for hydration.

"And they get a sense of, yeah, yeah, this is good habitat. And then they stay, hopefully stay put, sort of get their way, worked into the plant, hopefully lay some eggs on those plants. And then we can very gently take the netting off in an attempt to not sort of disturb them in the hopes that they actually still stay put," Parker-Shames said.

MORE: Locally extinct butterfly species returned to San Francisco's Presidio

For the Presidio, it's the latest in a string of native reintroductions, ranging from coyotes, to pond turtles to the Western Fence Lizard.

And they believe partnering with the Academy of Sciences could offer new opportunities.

"Absolutely. It's a place of experimentation and innovation around conservation in the 21st Century," Stringer said.

A living lab, with the potential to bring native environments back to life. The teams will be keeping a close eye on the butterflies, which were marked for future identification -- and using a platform called iNaturalist, which allows volunteers to help as well.