(A pin handed out after the Bioblitz of the Silvery Blue Butterfly, current star of a rewilding project in the Presidio.) FoglineSF.com
Lately, I have been on the lookout for some fun activities to help me re-engage with nature. I spend a lot of time in Golden Gate Park for exercise and relaxation, but I was in search of something I could do with others in the community that would also be educational. The perfect opportunity popped up on parksconservancy.org: the City Nature Challenge.
The City Nature Challenge I took part in was the Bioblitz at Lobos Creek. It gave community members an opportunity to become scientists for a day by looking for and identifying the flora and fauna of Lobos Creek in the Presidio. No special skills were required. This event was a part of a four-day international event. We learned that by locating and documenting our observations, we were helping scientists study and protect the wildlife and plants of the area.
History of the City Nature Challenge
This event started in 2016 as a competition between Los Angeles and San Francisco to locate and document wild plants and animals in their communities as a citizen science initiative. It has since grown into an international collaboration. Last year’s observations totaled over 3 million. La Paz, Bolivia, ranked first globally in submissions with 148,865, followed by San Antonio, Texas, with 133,953.
The Bioblitz at Lobos Creek in the Presidio was organized by the Golden Gate National Parks Conservancy. They recruited naturalist volunteers with expertise in birding, insects, and plant life to assist the participants. We had a quick tutorial on using the iNaturalist app for logging observations, grabbed some binoculars, and headed off to explore!
On the iNaturalist website you can find a checklist of species local to San Francisco to inform your own bug hunting and plant hunting missions. Earn titles like top observer or top identifier on the site’s leaderboard.
The volunteer guides were amazing at spotting wildlife. A couple of them demonstrated their ability to identify local birds based on their unique vocalizations. With their guidance, I learned how to photograph the insects and use iNaturalist to identify them by their scientific names. During our search, we observed an Allen’s Hummingbird perform its J-shaped courtship dive, pill bugs doing “pill bug things”, a Variable Checkerspot Caterpillar, a dung beetle, and several Yellow-faced Bumblebees buzzing in the flowers.
We also had excellent guides helping us spot and identify flora. We located The San Francisco Wallflower, a special plant that plays a significant role in the biodiversity of the Presidio’s coastal dunes. It attracts butterflies and many other beneficial insects.
We learned about the Silvery Blue Butterfly that is being rewilded in the Presidio as an ecological surrogate for the Xerces Blue Butterfly that was lost to extinction in 1943. The Xerces Blue was the first American butterfly species that went extinct due to urban development. Researchers from the Presidio Trust, the California Academy of Sciences, and Revive & Restore identified the Silvery Blue as the closest relative to the Xerces Blue through genome matching. A specific population of Silvery Blues was chosen due to its adaptation to coastal, foggy conditions.
Fun Fact! The Silvery Blue butterflies that were transported from Monterrey County to the Presidio were fed fruit-punch flavored Gatorade on Q-tips during the journey to keep them hydrated.
Although I didn’t see a Silvery Blue during the Bioblitz, I now have the knowledge to identify one in the future and understand just how special they are to the Presidio. I thought about times I have walked through the park and never taken the time to notice the life that is around me: a butterfly’s cocoon, a tiny beetle, or a milky yellow flower that draws insects to it. The impact of an event like this is the power it has to reveal what seems hidden. And once you see the beauty of nature in its smallest details, you can’t help but want to protect it.
I came away from this experience having learned so much about the coastal dune ecosystem of Lobos Creek, the importance of the conservation work being done there, and the ways in which I can help support these efforts as a citizen volunteer.
I also learned about the Golden Gate National Parks Conservancy, the local nonprofit partner of the National Park Service. They act as a critical bridge for funding and labor that the federal government does not provide for restoration and preservation, wildlife conservation, and climate resilience. As of 2026, San Francisco is experiencing shake-ups due to the firing of the Presidio Trust board and proposed funding cuts to the National Park Service, which governs the Golden Gate National Recreation Area including Muir Woods, Alcatraz, and coastal lands. If you have an interest in helping the Parks Conservancy in their mission, here are a variety of ways to give your support.