Philadelphia City Nature Challenge 2021

Contact Name:
Navin Sasikumar
Filed in:
Things to do near Philadelphia, PA » Activities » Lifestyle

The Greater Philadelphia Area will be joining with cities around the world to see who can make the most observations of nature, find the most species, and engage the most people in the 2021 City Nature Challenge. Between April 30th and May 3rd take pictures of flora and fauna (animals, plants, fungi, microorganisms) and upload the pictures using the iNaturalist app. The more observations you can make, and the more friends you can get to do the same, the better Philly's chances of being a top citizen science city!

We have a full list of guided walks on our website (, but you can simply go out on your own into your backyard, a weedy lot, or your neighborhood park and click away. It doesn't matter if you don't know what you took a picture of, iNaturalist has a machine identification system that will help you identify the species in your picture. There is also a community of experts and other citizen scientists who will help with identification if the machine ID fails.

The City Nature Challenge is organized worldwide by the California Academy of Sciences and the Natural History Museum of LA and it originally started as a friendly citizen-science competition between the two cities in 2016. It has now expanded and had 250 cities competing in 2020. Philadelphia participated for the first time in 2019, with over 500 people participating across the 4-day period and making over 13k observations, and finding nearly 1600 species. Can we do better in 2021? It's up to you!

Just download the iNaturalist app on your cell phone and mark your calendars for this fun 4-day bio blitz. Top cities get bragging rights and who doesn't want a chance to tell your friend from NYC that we have more citizen scientists than them?




Time: 00:00 to 23:59


Venue Name: Various Locations in Greater Philadelphia

Street Address

Philadelphia, PA 19123


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