
What is the City Nature Challenge?
Started in 2016 as a competition between San Francisco and Los Angeles, the City Nature Challenge (CNC) has grown into an international event, motivating people around the world to find and document wildlife in and around their cities, using biodiversity recording apps and platforms like iNaturalist. Run by the Community Science teams at the California Academy of Sciences and the Natural History Museum of Los Angeles County, the CNC is an annual four-day global urban bioblitz at the end of April, where cities are in a collaboration-meets-friendly-competition to see not only what can be accomplished when we all work toward a common goal, but also which city can gather the most observations of nature, find the most species, and engage the most people in the event.
The 2023 City Nature Challenge will be April 28 – May 1. Participating is easy: just use iNaturalist to make and share observations of wild plants and animals in any of the nine Bay Area counties. Be sure to check back here as well for information about City Nature Challenge events happening throughout the Bay Area.
City Nature Challenge 2022 Results

San Francisco Bay Area City Nature Challenge 2022 Results

Special thanks to our partners
From getting the word out to hosting events, the Academy's Bay Area partners make City Nature Challenge the inspiring, empowering, and fun 4-day nature bioblitz that it is—and we are incredibly grateful. Click the links below to learn more about each group.
California Native Plant Society | California Lichen Society | Latino Outdoors | California State Parks: Candlestick Point SRA | Bay Nature | San Francisco Department of the Environment | Nature in the City | Presidio Trust | Golden Gate Audubon Society | California Native Plant Society Yerba Buena Chapter | Sutro Stewards | Golden Gate National Recreation Area | San Mateo County Parks | Sequoia Audubon Society | Bioblitz.club | East Bay Regional Parks | California Center for Natural History | Community for Lake Merritt | Oakland Zoo | Oakland Museum of California | Wholly H2o | One Tam | Marin Municipal Water District | Marin County Parks | Sonoma Ecology Center | Sonoma County Parks | Pepperwood Preserve | Napa County RCD | Saved by Nature | Keep Coyote Creek Beautiful | Santa Clara Valley Audubon Society | Grassroots Ecology
Additional resources
Explore, observe, and document the plants and animals around you—even inside your house!
You don't need to venture too far from home to find exciting and surprising creatures! Download this PDF to get started.
Download this PDF and see if you can find all 25 of these commonly observed Bay Area (plant and animal) neighbors.
Don't have iNat yet? Download the app today and discover how fun (and easy) it is to document biodiversity in your neighborhood.
Have questions about the City Nature Challenge? Visit our Frequently Asked Questions page to find some answers!
The work we do utilizes iNaturalist to make biodiversity observations while building community around nature. It's a community-powered website and app that makes it easy to upload and share your observations in the field and to get help from other users with flora and fauna IDs.
Have questions about our community science programs? Want to get involved? Email us at communityscience@calacademy.org.
The Academy community science team is Rebecca Johnson and Alison Young