City Nature Challenge 2026

General
1

Dear iNat Forum Community,

With the City Nature Challenge approaching, we wanted to reach out and make sure that there is an open line of communication between the iNaturalist community and City Nature Challenge Global organizing team. As has been mentioned in other forum threads, the City Nature Challenge is organized by the California Academy of Sciences and the Natural History Museum of Los Angeles County, and most, though not all, projects are hosted on iNaturalist. In recent years, iNaturalist has taken on a greater partnership role, but they do not run the City Nature Challenge. We are incredibly grateful for iNaturalist’s support and to the iNaturalist community for all the extra work of identifying that happens during and after the City Nature Challenge. We, as the Global Organizing team, organize the thousands of local organizers who organize their cities and participants. With numerous problems emerging in the 2025 City Nature Challenge, we want 2026 to be a better experience for everyone involved, and we have made significant changes to the project and how we train and educate the local organizers, as noted below. Many of these changes were suggested by the iNat Forum. One of the biggest changes is that casual observations will not be included in the City Nature Challenge. We have worked to train our organizers so they can educate participants about the difference between verifiable and causal observations, but we know even if they are not included in the CNC, causal observations will still be shared on iNat, and that means more work for everyone. As a Global Organizing Team, we will be monitoring the iNaturalist Forum and reporting problems to our organizers. We have also created a form in which you can share problems you encounter directly with us. Thank you for the work you do as iNaturalist identifiers every day of the year.

As a reminder, here are the dates for the City Nature Challenge

April 24-27th: Observation period

April 28th-May 10th: Identification period

May 13th: Results Announced

Thanks so much for all you do,

Rebecca Johnson @rebeccfay

Amy Jaeker- Jones @amyjaecker-jones

Co-Directors, City Nature Challenge

Three Notable Changes to City Nature Challenge 2026 (this will be a journal post reminder to all of our organizers and participants)

Not new this year, but it is worth a reminder that the City Nature Challenge is not a competition and we do not recognize “winners.” The project pages on iNaturalist no longer say Leaderboard thanks to a recent update by iNaturalist, but they can show projects sorted by descending number of observations, species, and people. We encourage folks to move past this and focus on overall contributions that benefit your community and biodiversity worldwide. Be sure to check out the results pages on our website.

2026 changes -

  1. More time to upload observations:

    1. Observers now have more than a week (up until May 10) to work on uploading all the observations made during the April 24 - April 27 event time frame.

    2. The results for YOUR CITY will be whatever the numbers are in your city’s project on May 10, 2026.

    3. Global results will be announced around 2pm Pacific time on Wednesday, May 13th

  2. Collaboration and quality over quantity:

    1. Lots of poor photos, repetitive observations of the same species of plant in a field, observations of captive animals, or photos with not enough information to make an ID, are some of the recurring problems associated with past CNC events, when participants focused on numbers and leaderboards.

    2. At its heart, iNaturalist is about connecting people with nature, and CNC agrees with that philosophy. This year, CNC urges observers to slow down and notice the nature all around us. Making good quality observations provides the framework of data available to researchers and public policy makers for their work. Help us celebrate and protect biodiversity by taking these steps. With all of the folks around the world engaging in CNC for four days this April, we believe this will be a collaboration of epic proportions, showcasing our collective love of our shared natural world.

  3. Excluding casual observations:

  4. Beginning this year, casual observations will not count for the City Nature Challenge. This includes pets, animals in a zoo/aquarium, plants in your garden, potted plants, plants at a botanical garden, people, etc.

  5. If you do make an observation of something that you know is captive or cultivated, IT IS IMPORTANT TO MARK THOSE OBSERVATIONS AS CAPTIVE/CULTIVATED. Observations marked captive/cultivated won’t show up in the City Nature Challenge project, but they will still exist on iNaturalist.

Understanding casual observations and avoiding the three P’s (people, pets, and potted plants): Casual observations may be defined as those that are of captive/cultivated species and/or observations that lack sufficient data, such as evidence (photo or sound), date, or location. In order to have one umbrella project, we need to have a standard set of project criteria. Therefore, casual observations will not be accepted in any CNC project.

We encourage organizers and event hosts to remind participants to focus on making observations of wild plants, animals, insects, fungi, slime molds, etc., and to mark anything that is not wild as captive/cultivated. We also ask organizers and our local partners to help keep the data clean by marking observations that are obviously captive/cultivated when identifying observations.

2

The wording is a good start, but it would be best if the projects were displayed in alphabetical order. That way finding who is “winning” would be too much scrolling for most people.

Because the projects currently have 0 observations, right now the umbrella project is listing the projects in alphabetical order. I would think it wouldn’t be too difficult to tweek the coding to have it stay that way.

Edit: I guess it might be difficult to change the coding of this one umbrella project without changing all umbrella projects.

3

Just wanted to let everyone know that we’ll be putting up a blog post in the next couple weeks (before CNC) that highlights multiple changes we’ve made to projects.

Specifically for sorting projects in ALL umbrella projects (not just CNC), project admins can now set what they’d like the default sorting to be when people first look at the project. The CNC admins have set it to default to alphabetically, so even when the CNC starts and observations start getting made, visitors to the page will see alphabetically at first, and they can then choose to sort by the other options.

4

As an active iNat observer and identifier, as well as a local CNC co-organizer (yes, it’s true, I do not sleep), I want to say thank you to the global CNC organizers for paying close attention to the issues raised by the iNat community around the 2025 CNC. Your responses of excluding Casual observations and allowing more time for iNat identifiers to help confirm and clean up CNC observations are much appreciated. Here’s to a great 2026 City Nature Challenge!

5

Signed up for two cities. I go to Asheville at least once a week and most of my activity is in the counties of that project, but on the 24th I have a continuing education class for surveying north of Shelby. Normally I spend the entire time indoors except maybe for lunch, but this class will include tree identification, for which I’ll be outside observing trees.

6

You might think a country with the reputation of Costa Rica would have numerous cities participating.

But there are exactly zero.

7

If you would like to organize a city in Costa Rica next year, you can learn more here.

8

Thanks for clarifying, Alison!

9

And organizing a local CNC is not hard. You just can’t expect to be incredibly successful in your first few years, but that’s ok; more and more observers participate every year no matter what, at least in my experience. On the other hand, Costa Rica is a perfect place for a CNC. Maybe I can find a way to get there for 2027….

10

There is also the Global Project - for my City is not …

11

И снова в эти даты я буду в глуши бродить, даже не в городе))

12

You can still participate if you’re not in the city, as long as the глуши you’re wandering in are in the region of the city.
(Извини, у меня нет практики по-русски)

13

Нет, мои выходы в глушь примерно такие)

https://www.inaturalist.org/observations?on=2024-04-28&place_id=186379&subview=map&user_id=leschij&verifiable=any

No, my trips into the wilderness are something like this)

14

Looks like в CNC нет города в Беларуси. You can still join the global project: https://www.inaturalist.org/projects/city-nature-challenge-2026-global-project

A nearby place is labeled “Bol’shaya Rusilovka Вялікая Русілаўка”. Why is the transliteration from Russian instead of Belarusian?

15

В Беларуси два государственных языка: русский и беларусский.
Но карты Гугл иногда удивляют тем, как на них отображаются названия населённых пунктов, да.
Belarus has two official languages: Russian and Belarusian. But Google Maps sometimes surprises with how it displays the names of settlements.

В этом отпуске я планирую много внимания уделить руинам водяных мельниц.

This vacation I plan to pay a lot of attention to the ruins of water mills.

16

As a regular participant and organizer of CNC, these changes are much welcome and appreciated. After the initial experience of going through, a lot of casual/low quality observations being uploaded, we have been trying to reach out participants and help them out eliminating junk observations. As identifiers we also try to mark as many possible within our city area. I’m sure we will see much more quality data with this changes in place.. With the increased time for identification will also be useful for follow-up and adding annotations or marking captive.
Many thanks to the organizing team!

17

Yes- if your city is not participating, you can join this project: https://www.inaturalist.org/projects/city-nature-challenge-2026-global-project

18

I’m actually glad that this year’s Colorado projects are region-specific for the most part, instead of tied to municipalities. It gives me a whole lot more scope without having to join multiple projects.

19

These changes are very welcome indeed. Last year I really struggled to meet the deadline for uploading all my observations. Having a 2 week upload & indentify period will surely help with data quality and provide much relief for me…. :grinning_face:

I am an “offline iNatter” if I may say so, in the sense I don’t use the app much and I don’t upload observations in “real time”. I prefer to use my camera to take pictures and take my time enjoying nature without being connected at the same time. When getting back home I offload my photos to my computer and select the best ones for uploading to iNat. It’s a lengthier process for sure, but it works well for me and I feel I can produce better quality observations this way.

However, to make things even more challenging, the CNC falls on the first weekend of the 2 weeks spring holiday here. Last year, after finishing my CNC round on Monday, we grabbed our bags and left for the station. During the next days I spent my time sorting thousands of photos and uploading obsevations on the laptop on the train or in the evening at the hotel after everyone else went to sleep… That was my late night schedule for the whole week, with my headphones on and a good beer, until way past midnight. And I made it on time, I could upload all my observations, but I had very little time left to help with identifications… not to mention that during the holidays I took thousands more photos of wildlife which had to wait their turn to get sorted after we returned home.

But I don’t complain, this year I am ready to start all over again, train already booked for Monday late afternoon after the CNC round… :grin: Nevertheless, having 2 weeks to finish uploading all my observations is great, I will have less worries about deadlines and hopefully more time to help with identifications also… and more time to enjoy the ride… :winking_face_with_tongue:

20

Кстати, да. Продление периода загрузки наблюдений до 10 мая удобно.
Я планирую 21 апреля-3 мая провести у родителей и почти каждый день делать выход на 8-12 км. Разобрать всё отснятое уже будет проще на своём компьютере, как домой вернусь.