City Nature Challenge 2020

After an incredibly successful City Nature Challenge 2019, with almost 1 million observations of 31,000+ species uploaded in 4 days by 35,000+ people, we’re already planning for City Nature Challenge 2020!

2020 is the 50th anniversary of Earth Day and the 5th anniversary of the City Nature Challenge, and we’re excited to celebrate those together. After getting feedback from the 2019 local organizers, the dates for CNC 2020 will be:
April 24-27: observation period
April 28-May 3: uploading and IDing
May 4: results announced!

If those dates work for you and you’d like to help organize the City Nature Challenge in your city, now is the time to let us know! You can sign up here:

General requirements for being an organizer are:

  1. Making monthly online meetings
  2. Creating and maintaining your city’s CNC project
  3. Promoting the CNC in your area including how to best participate
  4. Completing milestones in a timely manner (based on a timeline given to organizers)
  5. Agreeing to guidelines around logo use, talking to media, fundraising, partnerships, etc.

We’ll have our first meeting with new CNC organizers in September, and will start our planning meetings with all organizers (new and returning) in October.

Not only does the City Nature Challenge get people outside and making observations in your region, but it helps build the community of people who regularly make iNaturalist observations. Check out the bump in the baseline of active users (top blue line) after each CNC!:

We hope you’ll join us in building this community and being part of this worldwide celebration of biodiversity in 2020!


I’m curious why Berlin is on the city list for 2019, even though we did not participate :thinking:

Berlin used Naturblick rather than iNaturalist:


How big is an avarage city, in square km?

Average this past year was 5362 sq km. But the range was 2 - 34,082!


if Berlin uses Naturblick again, would it be possible to make an iNaturalist project as well? I would like to participate, but I Much prefer iNat to Naturblick (you also need a phone for that, which I don’t have). I think the same thing was done in 2018.

I cannot install Naturbick, is it only allowed for Germans?

Platform for the CNC is decided by the city’s organizers. The 2018 iNat project looks like it was made by a participant, and unfortunately those observations were not counted in Berlin’s totals that year.

The issue with using 2 platforms is that we have no easy way of combining numbers to get the city’s stats. I’d say the best thing to do it to reach out to the Berlin organizers to ask them if they’d consider using iNaturalist instead.


No clue! I don’t have much familiarity with the other platforms that get used for the CNC, except for Natusfera since it’s basically an old version of iNat.

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I can’t see why they wouldn’t allow you to…
the app is only for Berlin, so that might be why?

I have a question. If I participate in the next Challenge, how does it work with your current “Observations” page of your account? In other words, I don’t want a bunch of duplicate observations of stuff I already have, because it is part of the Challenger. Is there a way that it is completely separated from our regular observations?

I am wondering because #1 I am interesting in participating and would like to contact our city about joining, BUT #2, I would hate to recommend it and then sorta look like a jerk not to participate.

Bottomline, I don’t want to clog up my observations page. Thanks

Just like with all projects, if you go and make observations for the CNC, they will show up in your observations. When you say “duplicate observations” do you just mean observations of species you’ve already observed before?

Yes, it would end up being a bunch of duplicates. Plus, it’s been my personal purpose to only document what I find in my yard. The City Challenge would be observations from all over the city.

I may be in the minority on why people make observations, but photography is sort of my first hobby and I made “my yard” the subject matter.

Nothing wrong with compiling a species list for your yard. I do it too (though i also add a bunch of other stuff). It’s the best way to track changes because you’re there so often.

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