What is happening? 

Every year, cities across the globe come together for a friendly, nature-focused competition known as the City Nature Challenge. This exciting event invites people of all ages and backgrounds to explore the natural world around them and share what they find, all through the community science platform, iNaturalist. 

Launched in 2016 by the Natural History Museum of Los Angeles County and the California Academy of Sciences, the City Nature Challenge has grown from a local event into an international celebration of biodiversity. What started as a competition between two cities has expanded to include hundreds of cities on nearly every continent. 

The mission is simple: to engage people in observing, recording, and identifying as many wild species as possible in urban environments over a short period of time. 

Why it matters 

This isn’t just a competition; it’s a huge contribution to science. The observations you make help researchers track species distributions, monitor changes in local ecosystems, and better understand urban biodiversity. Plus, the data is open and accessible to anyone, contributing to conservation efforts and environmental education worldwide. By participating in the City Nature Challenge, you’re helping cities understand the wildlife that lives alongside us, and how we can protect it. 

Through the City Nature Challenge, you’re getting involved with nature, helping to create a global snapshot of biodiversity, contributing to real scientific research through open access data, and raising awareness about the wildlife that lives right alongside us in our urban environment. 

Get involved 

Whether you’re a seasoned nature enthusiast or someone who’s just curious about the wildlife in your backyard, there are plenty of ways to jump into the City Nature Challenge. Your first step? Download the free iNaturalist app and get familiar with how it works—this powerful tool turns everyday observations into valuable data for science and conservation.   

Check this map for every location participating in the challenge. 

Once you’ve got the app set up, there are two main ways to contribute to this global urban biodiversity effort: 

1. Observe and Record (April 26–28, 2025) 

  • This is the fun, fieldwork part! During these four days, your mission is to document as much urban nature as you can, everything from mushrooms and mosses to birds, bugs, and beyond. 
    • Snap photos or record sounds of wildlife in your area. Yes, even that dandelion growing through the sidewalk counts!
    • Make sure your photos and audio recordings are clear and detailed enough to help others identify the species: here’s a helpful guide and a video on taking great iNaturalist observations. 
    • Once you’ve uploaded your observations to the app, double-check the date and location are correct. This ensures your sightings can be verified and counted toward the challenge. 
    • Your contributions will be reviewed by the iNaturalist community, and with enough confirmations, your data can become research-grade, which is real science in action! 

2. Help Identify Species (April 29–May 4, 2025) 

  • After the observation window closes, it’s time to dig into the detective work. This phase is all about community science and helping others identify what they’ve seen. 
    • You don’t have to be an expert! Even helping sort observations into broad categories (like “plant” or “insect”) is a big help.
    • If you do have some background in biology or a special interest in local species, this is your time to shine by confirming or suggesting IDs for others’ submissions. 
    • Every identification helps build a more accurate and complete picture of local biodiversity. 
    • Check out this guide and video for utilizing the identify tab on iNaturalist. 

 

The City Nature Challenge is about more than just counting species. It’s a celebration of local ecosystems, a call to reconnect with the natural world around us, and a way for anyone, no matter their background, to contribute to real scientific research. 

So, grab your phone, head outside, and see what you can discover. Your observations might be the key to a better understanding of your city’s ecosystem. Everyone is welcome, no experience necessary! Just bring your curiosity and a sense of adventure. 

Information from City Nature Challenge and iNaturalist.