Stories in Maryland/DC

City Nature Challenge

Discover and document the biodiversity of our urban spaces.

A young girl crouches down next to a tall leafy plant to take a photo with her cell phone.
Bioblitz A girl takes a photograph of a species of plant to upload to iNaturalist. © Devan King/TNC
White circle with an irregular edge showing the outline of tall buildings and animals on a green background with the words City Nature Challenge in the center.
City Nature Challenge Connect with nature. © CNC

Explore Your World

× White circle with an irregular edge showing the outline of tall buildings and animals on a green background with the words City Nature Challenge in the center.

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 2023 takes place April 28 - May 1, 2023

Use the iNaturalist app to join a CNC project for your city or area, and head outside to snap photos of plants, fungi and wildlife. Don’t let the word “city” fool you—observations can be made anywhere, including your own backyard!

A closeup of a mayapple, a delicate white flower with five petals that gently curve inward towards a yellow center.
Mayapple Podophyllum peltatum. The common name refers to the May blooming of its apple-blossom-like flower. © Kent Mason

During City Nature Challenge, people across the globe photograph and upload images of nature to, contributing to our body of knowledge and—hopefully—helping their city win an accolade. 67,220 participants in more than 400 cities around the world made 1,694,877 observations during 2022's CNC.

The District of Columbia rose to the occasion, ranking second globally for number of participants (just behind La Paz, Bolivia) and fifth for number of observations. 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 put in a strong performance for number of observations and species identified. Out of the 8,016 observations made in the city, more than half (57.36%) are considered research grade, meaning they can be used by scientists around the world.

Maryland/DC Director of Land Conservation Deborah Barber is an avid member of the CNC community.  Here she shares her City Nature impressions and observations.

What kind of wild species can you spot at one-minute past midnight on a rainy spring night?

That’s the question DC-area community scientists ask themselves each year. There’s stiff competition to be the first person to post a photo of a wild organism to the iNaturalist app and become Washington, DC's first City Nature Challenge observer.

A close up macro view of a black fly sitting on a dried brown leaf.
Flesh Fly (Family Sarcophagidae) observed during the 2020 City Nature Challenge. © Deborah Barber

The event has grown by leaps and bounds since it began in 2016 as a friendly competition between San Francisco's California Academy of Sciences and the Natural History Museum of Los Angeles County. The aim remains the same—find out which city can spot the greatest number of wild species, find the most diversity of species and engage the most observers. 

One exciting find for the DC metro in 2020 was a white-spotted slimy salamander (Plethodon cylindraceus) observed by a high school student in Arlington, VA. Endemic to the eastern US, this was the first sighting recorded in the county since 1977.

Zoom In, Zoom Out

iNaturalist, like The Nature Conservancy itself, is both deep and broad, highly local and powerfully global.  Zoom in, zoom out, you’ll see amazing things at every level.

Two beetles sit on a dark green leaf. The insects have a black body with a reddish cream marking on the back. Two black stripes on their backs resemble wings.
Asian Lady Beetle (Harmonia axyridis) pupae on plant in Lyon Park, Maryland native plant garden. © Deborah Barber / TNC

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. 

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.

City Nature Challenge Observations

Discovering the wild world in Washington, DC.

Three children face a tall green bush examining the thick leaves. They are each holding long handled butterfly nets.
View of the front of the US Capitol building through the branches of a cherry tree. The branches are covered with dark pink blossoms.
A night photo with flash of a small rabbit sitting in a suburban front yard. The rabbit is sitting on a bare patch of dirt next to a wide concrete sidewalk.
View looking up through a shallow plastic container of a four-legged winged insect. The insect has a thin body and nearly translucent wings.
Two women stand on opposite sides of a large tree trunk, smiling and posing while hugging the tree.
Macro, upside-down view of a brown spider crawling on a
Woodlouse Spider (Dysdera crocata) One of the first observations of the 2019 City Nature Challenge, spotted at 12:05 a.m. © Deborah Barber

Explore Your World

There are many ways to look for nature in your home or backyard.

Discover the plants that are growing on their own and the insects and pollinators that live in and around our homes and yards. You never know what you mind find!


Insects are probably some of the easiest organisms to find in and around our homes, since they’re abundant and incredibly diverse! But where should you look to find them? What can you use to catch them?

These sites provide some guidance on how to find and temporarily hold insects. Be sure to release them after you've posted your observation on iNaturalist!


Setting up a light and a sheet to attract moths is a simple and easy way to bring more nature into your backyard. Photographing moths on the sheet is easy, and you’ll definitely attract other flying insects as well!

Science Friday has a great set of instructions for observing moths, and the Devon Wildlife Trust's video shows how to build your own moth light to attract a wider variety of moths. (Note: in the video, "torch" is British for flashlight.)

How You Can Take Part

It's never too early to start honing your observation skills! It’s easy to get involved using the iNaturalist app (free on the App Store and Google Play). Just take a picture of a plant or animal and upload it to the app.

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!