City Nature Challenge - St. Louis

The City Nature Challenge is a fun competition that offers a terrific opportunity to connect with nearby nature. Join us April 30th-May 9th, 2021!

City Nature Challenge 2021

Perhaps now more than ever, connecting with nature is important to our health & well-being.

It is well-documented that time spent connecting to nature is important for people's health and well-being. The global City Nature Challenge is an annual opportunity for individuals in urban areas to compete with other cities around the world by making observations of plant and animal life.  An overarching objective is to celebrate connections with nature, and the global challenge encourages (1) as many people to make (2) as many observations of (3) as many species of wild plants, birds and animals as possible during the City Nature Challenge period.

2021 City Nature Challenge Special Notes

Pandemic Era Competition - Due to the Covid-19 pandemic, the 2021 City Nature Challenge will not be conducted as a true city vs. city competition. However, observations will still be counted and posted on a global leaderboard.  The City of St. Louis and partners in the St. Louis Metropolitan Region will again team up to participate in a modified version of the global event, which encourages safe connections with nearby nature through community-based (also known as) citizen science.  

Challenge Dates - The global City Nature Challenge dates are April 30-May 3, 2021 (Species Observations) and May 4-9, 2021 (Species Identifications). A special STL Region City Nature Challenge website will automatically collect all of the regional data entered on those days. Before and after the global challenge, we hope you will explore the flora & fauna around your porch or backyard, or just observe birds and other wildlife out a window. 

The Free App - To get started, download iNaturalist, which is the recommended app on your smart phone. Additional guidance and details are listed below, as well as upcoming virtual events and support opportunities. 

  • Android Phones: Download the free iNaturalist app from Google Play
  • iPhones: Download the free iNaturalist app from the Apple App Store

GeoPrivacy Considerations - If you would like to restrict access to a specific address, indicate "Obscured" on iNaturalist when uploading photos from your home. This will indicate a general area but not the specific address. If you indicate "Private" only you will see the observation, and it will not count.

Wild Species Are Preferred - Flora such as plants and trees that were planted in a yard should be noted as "Cultivated" in iNaturalist. Fauna such as pets should be noted as "Captive" in iNaturalist. Please do not upload photos of people.

Urban Biodiversity - In addition to being fun, a reason to get outside, and a wonderful educational opportunity, the City of St. Louis uses the City Nature Challenge as a way to help build the City’s Urban Biodiversity Inventory through citizen science observations. Information - such as photos taken on your smartphone - that is entered on iNaturalist can be used as an indication of where species are living at a given point in time. The iNaturalist observations collected before, during and after the City Nature Challenge will still be valuable pieces of the St. Louis region's biodiversity data. See below for links to the iNaturalist Projects.

(The April 2018 photo, below, shows numerous nests of wading birds at O'Fallon Park).

Walking by a Lake

Observe & Track Species with the free iNaturalist App 

Exploring Nature In & Around Your Home: The iNaturalist staff created this guide for participating in the City Nature Challenge where you live.

Wildlife Viewing Tips: Here are Top 10 Tips for Observing Wildlife, recommended by the Missouri Botanical Garden and Saint Louis Zoo.  

Using iNaturalist: To learn more about noting species observations with the free Naturalist app, check out these resources: 

City Nature Challenge & Nature ID Resources

How to Participate During the Challenge

Eagle on a perch

While the City Nature Challenge is held during late April-early May, the iNaturalist app is available year-round to help people make and identify nature sightings. The suggested first step is to download the free iNaturalist App at, as it is the easiest way to participate (check the Participant Guide for additional methods). 

If you would like to look for species that have a strong chance of being observed during the City Nature Challenge period, considering using the FIELD ID sheets at home or in open places like City Parks. Again, it is extremely important to heed all Covid-19 distancing requirements, precautions and best practices noted by local, state and national authorities.

Building the City's Urban Biodiversity InventoryUrban Biodiversity

If you are interested in noting the presence or absence of surrogate species (those species that are thought to be particularly good indicators of high quality urban biodiversity), please contact Catherine Werner, Sustainability Director, at for details. The City of St. Louis is attempting to collect urban biodiversity information throughout the year, not just during the City Nature Challenge. On this map, you can see the iNaturalist species observations made in the City of St. Louis. Below is information to a specific set of indicator species and urban biodiversity monitoring in the City.

  • Indicator/Surrogate Species: The City of St. Louis has worked with many biology and ecology experts to develop an urban biodiversity Indicator or Surrogate Species list for three key urban habitats: aquatic/wetland, prairie, and woodland/forest. Noting the presence (or absence) of a surrogate species can be an important indicator when assessing the quality of urban biodiversity areas.
  • Public Monitoring Locations: This map shows six Urban Biodiversity Monitoring priority locations in the City of St. Louis. 
  • An initial focus of biodiversity monitoring has been on public spaces, but it is equally important to learn about urban biodiversity in private and residential settings. If done in accordance with CDC and other local, state and national health and safety protocols, iNaturalist observations can be made of plant and animal species near where you live. Here are some tips on looking for nearby nature from the iNaturalist staff. If you do not want your specific location recorded, simply indicate "obscure" in the iNaturalist settings.

2021 STL City Nature Challenge Events

Due to the situation with Covid-19 and the need for physical distancing, there will only be virtual and self-guided City Nature Challenge 2021 events.

STL City Nature Challenge Page on Facebook

Biodiversity, Eco-Literacy & The STL City Nature Challenge

Video presentation by Catherine Werner, Sustainability Director (20 minutes long - April 20, 2020)



Related City Nature Challenge Resources

St. Louis Metro official City Nature Challenge April 2021 site

Ongoing City of St. Louis iNaturalist Urban Biodiversity observations

Ongoing Biome (St. Louis Region) iNaturalist observations

City of St. Louis Biodiversity Indicator/Surrogate Species List

City of St. Louis Biodiversity Monitoring Priority Location Map

Top 10 Tips for Observing Wildlife in the St. Louis Region

City Nature Challenge Field ID Guides for St. Louis Region - Spring Species

STL City Nature Challenge - Educator Guide

STL City Nature Challenge - Participant Guide

STL City Nature Challenge - Scout Leader Guide

Global City Nature Challenge website

iNaturalist app guidance and site

Covid-19 & City Nature Challenge FAQs

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