Bay Nature magazineSpring 2018

Urban Nature

The City Nature Challenge Returns April 27-30, and It’s Gone Global

March 30, 2018

A few years ago, Alison Young from the California Academy of Sciences and Lila Higgins from the Natural History Museum of Los Angeles County hatched an idea for a weeklong nature-finding competition pitting the Bay Area against Los Angeles. They launched the first City Nature Challenge in 2016, and when a reporter from The Los Angeles Times called about the event, she asked Higgins how many observations of animals and plants—be they birds or blades of grass—the team thought they’d get. Ten thousand, Higgins said.

“When I said 10,000,” she says now, “I was like, ‘Mouth! Shut up!’ We’re never going to do that!”

Yet in one week in April 2016, more than 1,000 people in the two regions recorded more than 19,000 observations in the nature app iNaturalist. Los Angeles scored a narrow victory, and Higgins became the seer of the City Nature Challenge.

Last year the competition expanded to 16 cities across North America, and Higgins predicted 100,000 observations. It seemed “equally insane,” she says, especially given that the time window was shortened from a full week to three days. Didn’t matter: more than 4,000 people recorded more than 125,000 observations of more than 8,000 species, with Dallas–Forth Worth emerging as the winner with 23,957 observations.

This year, April 27–30, the competition goes international, with more than 60 participating cities worldwide, including London, Berlin, Mumbai, Kolkata, Sao Paulo, Tokyo, Bogota, Kuala Lumpur, and Hong Kong. There will be free bioblitzes and nature-finding hikes daily in every county in the Bay Area; you can find a list at

You don’t have to join an event to participate (or even know you’re participating): any observation added to iNaturalist counts if it’s made in one of the competing cities. Just find something alive, or even evidence of something that once was alive, like scat or a shell. Take its picture, and upload the photo to the app along with its location and your best guess at what the thing is. During the second part of the competition, from May 1 to 3, experts will weigh in with identifications for as many observations as they can, to try and determine which city or region found the most species. Winners in three categories—most observations, most species, most participants—will be announced on May 4.

So. How many observations does Higgins say they’ll record this year?

“I’ve thought 500,000,” she says. “Which sounds ridiculous to me. Maybe I should be more conservative.”

Join Bay Nature and the San Francisco Public Library to bioblitz San Francisco’s Noe Valley at 3:30 p.m. on April 27. Or join us the following week for a party to identify species observed during the challenge. Find an event near you at

About the Author

Eric Simons is a former digital editor at Bay Nature. He is author of The Secret Lives of Sports Fans and Darwin Slept Here, and is coauthor, with Tessa Hill, of At Every Depth: Our Growing Knowledge of the Changing Oceans.