City Nature Challenge

The City Nature Challenge (CNC) is an international community science effort to discover and document plants and wildlife in cities across the globe. The observation period of CNC 2022 takes place April 29 - May 2, 2022

As with so many aspects of our lives, this global bioblitz continues to feel the impact of COVID-19. To embrace the healing power of nature, and encourage the celebratory aspect of the CNC, participants are encouraged to safely document biodiversity in whatever ways they can, including from the safety of their own homes.

People across the globe photographed and uploaded images of nature to iNaturalist.org to contribute to our body of knowledge and—hopefully—help their city win an accolade. 419 cities across 44 countries participated in 2021's CNC.

The District of Columbia rose to the occasion, ranking second globally in both number of participants (behind San Francisco) and number of observations (after Cape Town, South Africa). The lovely native mayapple (Podophyllum) topped the list as the number one plant species observed. Other interesting finds in the area included silver-haired bats and alien-like eggs from the spiny assassin bug.

Baltimore saw a record high for number of observations and species identified since the city began participating in 2018. The number one reported plant species in Charm City was the common blue violet (Viola sororia). Out of all 1,917 species observed in the city, 44 were considered protected,threatened or endangered.

Zoom in: I posted a photo of a ladybeetle larva in my garden, then learned from other users that the Asian species has forked bristles; the natives’ bristles are single-tipped. Now I know what to look for! Zoom out from any observation and you can see the global distribution of that species.

With a few more clicks, you can see how each organism fits into the entire taxonomical tree of life. Likewise, with TNC, I can spend a morning at work monitoring a plant found only in one small patch in Maryland, then in the afternoon share conservation strategies with TNC colleagues from Mongolia, China or Indonesia.

iNaturalist and TNC are both constantly learning and evolving. iNaturalist’s computer vision, added in 2017, becomes smarter as users identify photos of organisms.

When I started working at the Maryland/DC Chapter, one of my first plant monitoring projects was documenting the steady decline of a rare wildflower, Canby's dropwort (Oxypolis canbyi). Now we have learned that it needs fire to thrive. We are burning its habitat and watching it multiply, and we are working with partner organizations to develop regional strategies to develop a more fire-friendly culture for natural area managers.

Friendly Competition

I’m not normally a competitive person, but when the City Nature Challenge begins, I will be out at midnight helping the DC area make the best possible showing. In 2020 the region ranked 3rd for both number of observers and number of research grade observations and 9th for number of species.

So, what observations have DC-area iNaturalists submitted in the moments past midnight? Photos of a flashlight-illuminated ichneumonid wasp, a shield lichen, raccoon tracks on a trash can, a kitchen pantry moth and an audio file of a mockingbird singing its late-night song all have contributed to our picture of the diversity of life in Washington, DC.

Explore our collection of recorded webinars for guidance and tips for recording observations in the iNaturalist app, engaging children with nature using the iNaturalist and Seek apps, tips and tricks to elevate your nature photography, and guidance on properly identifying CNC observations.

When you're ready to start observing, use our photo gallery of local TNC preserves and partner sites below to help you get started or explore your own backyard or neighborhood parks. There's nature all around you!