There may not be a corner of San Francisco with a more diverse wildlife than the Presidio.

The park is home to over 200 species of birds, sand lizards and gray foxes. Even coyotes have space to keep their pups on the trails.

And now a small species that has been missing in the park since the 1970s is thriving there again.

The colorful variable checkerspot butterfly is back thanks to a project launched in 2017 by wildlife managers at the Presidio Trust.

“It’s an indication of a healthy ecosystem – that there are enough food resources for them and other grass-dependent insects, and that they in turn provide food for other creatures in the chain,” a Presidio Trust spokesman said in a statement. “This pagan abundant insect community will produce happy fat birds and lizards and more.”

The butterflies left the area in the mid-1970s due to habitat loss. The caterpillars of the species require very specific types of native plants to survive. In this case, the Checkerspot’s host flora is the California bee plant and a sticky monkey flower. These plants were lost when urban development crept into the park, leading to the local extinction of the species nearly 50 years ago.

The variable checkerspot butterfly.

Wikimedia Commons

The restoration of these plants and other coastal scrubs in the park over the past 20 years created a welcoming habitat for the checkerspot, but the little bugs needed help getting home.

“This butterfly can’t fly very far, the caterpillars can’t crawl very far, the nearest population of these butterflies is very far … It takes human effort to bring it back,” said wildlife ecologist Jonathan Young on a video from the Presidio Trust the project.

Hundreds of the caterpillars were found in the same California bee plant on Mount San Bruno, placed in an ice box to temporarily slow their metabolism, and driven to their new home in San Francisco.

“They took off. You can see them in all these restored areas of the park,” said Young on the ABC7 news this week.

Thanks to years of restoration efforts, strolling through the Presidio in the spring, especially around the point of inspiration, you can see a brown butterfly fluttering past with white, yellow, and red checkerboard patterns.

The next target for the reintroduction to the Presidio is the Californian marigold butterfly – the team is currently finding, catching, and icing them in the Marin Headlands – and hopefully one day they will bring San Francisco’s official bird, the plump Californian quail be back to town.