CNC 2024: Updates

The City Nature Challenge had to set up two umbrella projects this year because they maxed out the number of collections project allowed in an umbrella project, one for all the City Nature Challenges in North and South America and the other for Eurasia, Africa and Oceania.

In the NA/SA project, the top 5 most commonly observed species as of this writing are the American Robin, Mallard, Canada Goose, Western Honeybee and Red Winged Blackbird while in the E/A/O project the top 5 are Garlic Mustard, Lawn Daisy, Common Dandelion, Great Stinging Nettle and Ribwort Plantain.

Looking at the 2023 species list when all the projects were under one umbrella, the top five were Mallard, Western Honeybee, Dandelion, Garlic Mustard and American Robin.

Breaking the world into regions like this means that the La Paz and Cape Town are no longer directly competing but Cape Town is at the top of their regional project with 23,427 (hopefully with very few nursery plants @dianastuder) while La Paz has 62,752.


This year I am concentrating on IDs for the Rest of Africa. Struggling more with D#mned Dicots, than garden plants.

But still clearing the Cape Peninsula for Kingdom Disagreements, and plants above family. Those two bunches deserve a second chance.
In our top 5 is guineafowl feathers - such eye candy with the spots

Graz in Austria was leading when the first results rolled in. We have … edged past them - with Hong Kong well in the lead! San Antonio TX a close second. Sorting by number of species.


…all animals, mostly birds.

…all weedy plants.

There is bound to be an interesting story there.


Interestingly, the top 5 in Pittsburgh are all weedy plants (if you consider mayapple weedy, otherwise only 4 of them are) – there’s only one bird in the top 36. I do wonder why it’s such a big difference.

Sure they are. Combined stats are on


It’s not just La Paz. There are currently three cities/projects in Bolivia in the top 8 of North and South American cities according to the umbrella project overview. Bolivia is awesome.


@cigazze, As a newbie to CNC and amateur observer using a cell phone camera, I can almost guarantee that the fact that plants don’t fly away explains the difference. Wild plants are much easier to photograph than any wild animal! And participants are adding “weedy” plants because they’re confident they are “wild” rather than cultivated.


That makes perfect sense, but it doesn’t explain why the Americas have so many observations of animals.


Individual places outside the Americas have lots of animals. But when you look at species found all over Europe, Asia, Africa and Australasia, there aren’t a lot of animals or birds found everywhere around the world.

It a … Dicot!
Animals are so much easier to sort out. (I concede - insects are also difficult)

@arboretum_amy beyond the blunt tool of bigger is better - I wish CNC offered some targets for the MANY smaller projects, which can never compete on observer or observation totals. Species numbers are also handicapped by the designated area covered, and which habitats are included. Cape Town has mountains and ocean. La Paz covers a huge altitude difference. Hong Kong surprises me by a wild green interior (since we usually see pictures of the high rise rim)

We need a ‘handicap’ system like golf. We can compete against what we saw last time but that is not exciting, a minor challenge.

Best biodiverse square kilometre? First obs of a new sp? First living obs? But would prefer not to set up a target for poachers. ??


I bet the global organizers are running as hard as they can just to do what they currently accomplish. Plus, they are emphasizing getting everyone involved with nature in their backyards, so setting up competitions runs contrary to that. Not everyone can find a new species or lives in a highly biodiverse area. Many people don’t understand there’s a difference between an insect and a spider. Or a cultivated plant vs. a wild plant, for that matter. I’d rather see lots and lots of people learn those sorts of basic facts than compete on any level.


No - I want a target for the newbies. That is why I ID for them first.
5 flowers ? 5 bugs ? Just 5 whatevers ?
It can be a kind small ‘welcome hug’ - you done good! - sort of target.

If they wanted to, individual project organisers could set a target that works for them.

(Quietly horrified to be the leading identifier for Maputo - shows how dire the need for identifiers is away from well iNatted big cities and universities)


Yes I remember when I was first introduced to CNC, I was baffled how participating “cities” just get to choose the size of their area. In CA most teams are entire counties, which in the south are large, and actually team Inland Empire combined two of the state’s largest counties into one team, 27,263.39 square miles or 70,611.86 square km, no doubt bigger than some whole countries… and let’s not get started on how late April isn’t the ideal time of year in every location.


I also stepped out of my usual business (usually going through old needs IDs) and doing specific CNC spider IDs at the moment … covering the Europe/Asia/Africa umbrella for now (not much help in Oceania I fear, aside from the occasional push to family… you guys are so far off from the rest and have so specific wildlife :slightly_smiling_face:)


I wasn’t really sure I understood what you meant at first, but I think I see now - you’re saying there are more individual species in the Americas that are widespread across a larger proportion of the search area, so those species are able to climb to become most-observed species in ways that species in the world outside the Americas can’t, right? This was a good reminder that a top X species list isn’t really representative of what’s going on more broadly.

I got curious about the overall ratio of animal observations, so I searched the observations in the two projects for animals. It turns out the Americas actually don’t have more observations of animals - they have proportionately fewer! When I checked a few minutes ago, about 27.3% of CNC observations in the Americas fell under Animalia, while in Europe, Asia, Africa and Australasia the CNC observations under Animalia accounted for 29.1%.


If we’re looking for options for competition, one option that comes to mind would be to compare the project’s findings with all historical findings in that same area prior to the challenge, but still rank cities in terms of how well they revisited/consolidated their coverage of their area. You’d end up with two values of interest that projects could compete on - who managed to re-observe the highest percentage of previously observed species from their area, and who managed to add the largest number (or percentage, or something else) of first observations of a species within their area.

Seasonality would limit what could be accomplished there, but maybe one could adjust for seasonality by comparing the project with historical observations from the dates of the project +/- two weeks or so across previous years.

The downside is that those values are probably less intuitive and tougher to explain to the broader user base.

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I can’t say it worked but for a Bioblitz I organized, I gave easily achievable observation targets related to iNat’s iconic taxa. I chose to exclude fungi, protozoa and reptiles because I knew those were either absent from the Bioblitz boundary or too difficult to find/observe. Ultimately the Bioblitz flopped as a friend and I were the only participants, but I think giving small collective or individual targets can help encourage participation. Collective targets in particular may emphasize the social aspect of bioblitzes


Yes, that is exactly what I meant. Thanks for trying to understand!