City Nature Challenge 2025: Pima County, Arizona, April 25-28
2024 Pima County Results:
Total Observations: 4022 Total Species: 911 Total observers: 341
Broad-reaching science depends on diverse community participation.
Community science has been happening ever since humans could communicate, though in recent years the tools we use and our ability to share and communicate information have exploded! Community science relies on non-professional scientists and community members to contribute to crowd-sourced data collection and analysis. Our collective observations of plants and animals create an important global record of biodiversity and changes in our environment, thus using the power of the many to answer some of the biggest questions we face today.
You do not need to have scientific training to contribute to our understanding of the natural world; the study of nature is for everyone. We seek to provide community science opportunities through our own Pima County Master Naturalist projects and those of our partners. These projects aim to connect people to nature and to protect local diversity, all while supporting a growing community of local naturalists. We want to emphasize that everyone in the community is encouraged to participate in these endeavors; community science benefits from the diverse viewpoints, traditions, and skills of everyone in our community.
The Arizona Master Naturalist’s Pima Chapter is hosting the 2025 City Nature Challenge in Pima County, Arizona. Be a part of this community science project by participating in this worldwide effort to document the amazing biodiversity of our region.
April 25th through April 28th– Search for WILD plants, animals, and other creatures to see how many species you can find and show the world how diverse our region is. Add your observations to iNaturalist and they’ll automatically be included in the project.
April 29th through May 4th– Finish any last uploads and identify all of the observations in the project. Let’s see how many we can get to research grade!
Join the Pima County City Nature Challenge project on iNaturalist to get updates. We will add events below as they are confirmed. Visit the main City Nature Challenge website to learn more about the event and to see the list of the 400+ cities participating in 2025!
Joining the project is easy:
- Download the free iNaturalist app to your mobile device. iNaturalist is 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.
- During April 25-28, take photos to make observations of wild plants and animals in your house, your backyard, a park, your neighborhood – anywhere you find nature and can maintain safe social distancing. Check out this guide for finding nature in and around your home for ideas of where to look for species. Be sure to mark the observation as captive/cultivated if it’s not a wild organism!
- Upload your photos to iNaturalist. They will be automatically added to the Pima County City Nature Challenge project. Note that only photos taken in the April 29 – May 4 time range within the project boundaries of Pima County will be added.
- Learn more as your finds get identified, and feel free to help ID other people’s observations, especially during the April 29th – May 4th identification period.
- Results will be announced on Monday, May 5th!
Please help us spread the word about the City Nature Challenge!
City Nature Challenge Events
In Advance of the City Nature Challenge:
NEW!!! Check out a Community Science Kit at the Pima County Public Library (Joel D Valdez Main Library or Richard Elías-Mission Library). There are three kits available: 1. Exploring Biodiversity, 2. Measuring Light in the Night, and 3. Observing Pollinators. The biodiversity and pollinator kits are perfect to get you ready for and to participate in the City Nature Challenge!
Upcoming events will be listed here
Date / Time
Location
Host
Community Partners
The 2025 Pima County City Nature Challenge is organized by The Pima County Master Naturalists in conjunction with the California Academy of Sciences and the Natural History Museum of Los Angeles County. We’re fortunate to partner with incredible organizations across Pima County for the City Nature Challenge! These partners help us get the word out, hold events, and make the City Nature Challenge the fun and educational 4-day nature bioblitz that it is.
Pima Master Naturalists 
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