WHAT:           

The end of April signals the annual City Nature Challenge, the largest, collaborative bioblitz on Earth! It’s fun and easy. Pull out a smartphone, download the free iNaturalist app, and make observations of local wild species of animals, plants and other living beings. The four-day biological survey invites everyone around the globe to make as many observations of wild nature as possible over one weekend, leading to a better understanding of urban biodiversity and advancing conservation research. 

 
City Nature Challenge 2026 kicks off April 24. People of all ages, backgrounds, and abilities across the Seattle-Tacoma metropolitan area (King, Pierce and Snohomish counties) are invited to participate. The global nature observation event helps drive community science by encouraging everyone to find and document wildlife living outside their windows, in their backyard, on their windowsills, and in their neighborhoods and cities. Individuals can participate or take the kids outdoors and make it a family affair. Nature enthusiasts can take their involvement to the next level by helping identify people’s City Nature Challenge observations in iNaturalist. 
 
Participate in City Nature Challenge and make your nature observations count! Last year’s Seattle-Tacoma City Nature Challenge logged 19,628 observations of 2,138 species, with 1,233 observers; participating. Join the 2026 City Nature Challenge: Seattle-Tacoma Metropolitan Area iNaturalist project to see the neat nature observations your fellow community scientists are finding! 
 
WHEN:           
City Nature Challenge takes place in two parts:  
Observe!  
April 24–April 27, 2026 
Take and upload pictures of wild plants and animals  
                       
Identify!  
April 28–May 10, 2026  
Help identify what was found  
 
HOW:             
Download the free iNaturalist app or access it on a computer.  

• Take photos of wild plants, animals and fungi anywhere in King, Pierce and Snohomish counties—your backyard, out your window, a city park—go explore! No photos of pets or cultivated plants, please! 
• Upload your photos to iNaturalist from your mobile device or via your computer.  
• Help identify as many observations as you can.  

Woodland Park Zoo offers City Nature Challenge supporting resources in Chinese, Russian, Somali, Spanish and Vietnamese.
 
EVENTS:           
Visit our City Nature Challenge Events page:

• Find out about City Nature Challenge meetups and join virtual and in-person sessions to learn how to observe nearby nature and share your observations.   
• Join your neighbors on one of many City Nature Challenge walks happening in the Seattle-Tacoma area.    

INFO:             

City Nature Challenge is the largest annual biodiversity census in the world. To date, more than 363,000 people have engaged in collecting more than 12.9 million biodiversity observations. In the Seattle-Tacoma area, local parks departments rely on nature observations made by community members, such as those collected during City Nature Challenge, to better understand and protect the biodiversity in the region’s natural areas.  
 
Woodland Park Zoo, Point Defiance Zoo & Aquarium, Northwest Trek Wildlife Park, Seattle Parks and Recreation, and other collaborators help mobilize people across the greater Seattle area to join a friendly nature observation challenge involving hundreds of cities across the globe.