Peterborough City Nature Challenge encourages residents to document local biodiversity

To culminate local Earth Week activities and to celebrate biodiversity, Peterborough is once again taking part in the four-day City Nature Challenge (CNC). It takes place from Friday, April 26 to Monday, April 29. The CNC is a global “bioblitz” competition engaging cities around the world. A bioblitz is a community-science effort to document as many plants, animals and other organisms as possible within a designated location and time period. This provides valuable information for conservation purposes. The main idea of the challenge is that cities try to outdo each other in terms of total observations, the number of species seen, and the number of participants.

Peterborough residents and visitors alike are therefore encouraged to get outside and discover the abundance of species that can be found in our yards, neighbourhoods and local greenspaces. Peterborough County residents are also encouraged to come into the city and take part. The CNC is also something that adults and children can participate in together. Sightings can be made anywhere in the City of Peterborough but must be recorded using the iNaturalist app. More about that below.

In Peterborough, we are blessed with nature all around us.  Knowing what species are present and where they are helps researchers and conservationists  study and protect them. By participating in the CNC, not only do you learn more about local nature – and feel more connected to the natural world – but you also make Peterborough a better place for you and other species.

Special launch event

To kick off the Challenge, the City of Peterborough, in collaboration with the Peterborough Field Naturalists (PFN), is hosting a community event on Friday, April 26 and Saturday, April 27 at Ecology Park on Ashburnham Dr.  Both days between 11 a.m. and 3 p.m., volunteers from the PFN will be on hand to share their knowledge and to provide help with using iNaturalist. Guided nature walks are also planned and, on Saturday, there will be children’s activities.

On April 26 at 11:30 a.m. Carlotta James of Three Sisters Natural Landscapes will be leading a family-friendly walk on the theme of pollinators and Peterborough’s role as a Bee City. At 1 p.m., the Otonabee Region Conservation Authority will talk about the history and ecology of nearby Meade Creek.

On April 27 at 11:30 am, a tree walk will be led by Vern Bastable, director of GreenUP Ecology Park and landscape programs. At 1 p.m., I will be leading a general nature walk.

Before arriving, be sure to download the free iNaturalist app to your mobile device and create an account. You can then take photographs of some of the species observed on the walks – or as you wander around on your own – and upload them to iNaturalist. They will automatically count towards the competition.

Late April nature happenings

The timing of the CNC is excellent. In late April a wide variety of migrant birds are returning. These include yellow-bellied sapsuckers, white-throated sparrows, ruby-crowned kinglets and the first warblers like the yellow-rumped and the northern waterthrush. Birds such as robins, grackles and blue jays are already nesting.

Wildflowers and even some trees are in bloom. They usually include marsh marigold, bloodroot, violets, and Dutchman’s breeches, along with alders, aspens, willows and even Manitoba maples. Some shrubs such as currants and red elderberries are usually in leaf.

As for invertebrates, late April sees the first dragonflies as well as butterflies like mourning cloaks and spring azures. There is also abundant bird and frog song. It’s even possible to upload song recordings to iNaturalist.

A global competition

The City Nature Challenge gives three awards each year to the cities that make the most observations, find the most species, and engage the most people. Last year, 66,394 participants from across the globe made almost two million observations and recorded more than 57,000 species, 75,000 of which were in Canada. La Paz, Bolivia took the triple crown with the highest number of observations (126,435), species (5,344) and observers (3,025). The most observed species globally was the mallard duck. Victoria, B.C. finished first in Canada with 8,604 observations, 1,414 species and 423 participants.

Due to poor weather and insufficient publicity, only 37 people participated in the 2023 Peterborough CNC. They tallied 574 observations and 298 species. Organizers are hopeful to surpass these numbers this year. We already know that Peterborough is home to at least 4,596 species thanks to the iNaturalist sightings of over 3,000 observers. Check out the Peterborough City Biodiversity project page at to see all that’s been observed. You’ll be amazed.

Let’s hope that large numbers of local birders and feeder-watchers take part this year. This could really boost the number of participants, observations and species. It would be wonderful if Peterborough could outdo Kingston in the CNC!

Using the iNaturalist app

For CNC sightings to be officially documented, participants must use the free iNaturalist app or the iNaturalist website. At its core, iNaturalist is a species identification and information platform that catalogues all sightings. It’s also a way for citizen scientists to provide important scientific data. And no, you don’t need to be an expert. Most people begin by exploring plants and insects in their own backyard or neighbourhood.  

To get started, download the iNaturalist app on your iPhone or Android device and create an account. You can also register via the website. Next, open the app and head outside with your smartphone, making sure the location (geotag) function is turned on. If necessary, the location can also be added manually.

Here are the instructions for using the app with an iPhone. For Android phone instructions, go to: When you find a species of interest, click on “Observe” and then on “Camera”.  It’s often best to take several shots in order to show different features – the flowers and leaves of a plant, for example. You can also use any pictures in your phone’s photo library. Your photo will appear on the iNaturalist “Details” page, along with the date, time, and location.

Click on “What did you see?”. The probable family or genus will pop up along with suggested species. You’ll see a picture of each species and whether it’s expected nearby. If you wish, click on the blue information circle to the right to see a larger photo, species description and a map of observations. Choose the species that looks most likely. If you feel it’s important to add more information, you can use the Notes space. Click “Share” and the sighting will appear on your personal Observations page. The sighting will automatically go to the “City Nature Challenge 2024: Peterborough” Project page and count towards the CNC.

It’s also likely that someone in the iNaturalist community will confirm your identification or suggest another species. You will receive an email letting you know. Experienced local naturalists will be needed from April 30 – May 5 to review and confirm the CNC sightings. This confirmation process helps to eliminate incorrect identifications, especially with tricky species like moths, lichens and fungi. You have until May 6 to upload your sightings to iNaturalist and have them count in the City Nature Challenge 2024.

What about birds?

Because it’s difficult to photograph birds with a phone, I use my zoom camera. Then, I bring up my best photo of the bird on the LCD screen of the camera and take a picture of the screen with my phone. I usually crop the photo before using it on iNaturalist.

Although the app itself is extremely powerful, you need to visit the website to appreciate all that iNaturalist offers. For a given species, you can click on “Explore” to see all of the observations in a given location. There is also a map page showing where – in Peterborough, for example – it has been found. It’s also possible to upload observations directly from the website.

To see all of the resources that iNaturalist offers, go to I also recommend watching the Peterborough Public Library’s iNaturalist how-to video at

            More information on the CNC can be found at

Drew Monkman

I am a retired teacher, naturalist and writer with a love for all aspects of the natural world, especially as they relate to seasonal change.