City Nature Challenge

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April 25 - April 28, 2025

City Nature Challenge, one of the world’s largest community science events, returns for its 10th year of connecting people through local nature and their communities. Kicking off Friday, April 25 at 12:01 a.m., the Challenge runs through 11:59 p.m. on Monday, April 28. From participating in organized biodiversity surveys to recording the wildlife in their own neighborhood, City Nature Challenge encourages community scientists of all levels to explore their local environment—all while contributing to biodiversity science and conservation and using free mobile apps like iNaturalist. Identification of photographed species will be crowdsourced through the online community April 29 – May 4, and results will be announced on May 5. 

How to Participate
For both budding and veteran community scientists, participation is easy. Photos taken during the Challenge can be uploaded to iNaturalist, where an online community of naturalists confirms species identifications.

Wildlife can be found in the participants’ homes, neighborhoods, backyards or anywhere else, and can be any wild plant, animal, fungi, slime mold or other evidence of life (scat, fur, tracks, shells, etc.). Whether participating in an organized habitat survey or making observations in their own neighborhood, participants can upload photos or sound recordings of their findings to iNaturalist or their city’s chosen platform via app or website where they can learn more about the plants and animals they find as their observations are identified.

Here in the Bay Area, joining in is easy! If you live in or are visiting any of the nine counties that touch San Francisco Bay, all you have to do is:

1. Download the free iNaturalist to your mobile device.

2. April 25 - April 28, 2025, take photos of WILD plants and animals anywhere in the nine Bay Area Counties (San Francisco, San Mateo, Santa Clara, Alameda, Contra Costa, Solano, Napa, Sonoma, Marin).

3. Upload your observations to share with the iNaturalist community. They will automatically be added to our San Francisco Bay Area City Nature Challenge project!

4. Learn more as your finds get identified!

Those not able to take photos or record their observations can still participate by helping identify species documented in their area during and after the Challenge. Many organizers in cities around the world will be hosting wildlife identification events Tuesday, April 29 – Sunday, May 4.