City Nature Challenge 2026

The City Nature Challenge 2026 took place this year from April 24 to May 10. It is a global, friendly competition in which nature observations are collected and shared: Which species can be discovered? Where is the greatest diversity documented? And is it even possible to record certain species for the first time during the event? The City Nature Challenge has now become a fixed part of my spring. Of course, I also wanted to contribute again this year to this international citizen science project.

As soon as spring begins, the City Nature Challenge comes into reach. This year it started on April 24, and until April 27, nature enthusiasts around the world were encouraged to collect as many observations from nature as possible. The City Nature Challenge is a global, friendly competition in which numerous cities take part.

Germany was represented again as well – including cities such as Berlin and Hamburg, as well as the metropolitan region of Nuremberg/Fürth/Erlangen, which joined in the shared observation and documentation of biodiversity.

For me, the focus is not on winning. I take part for Berlin – a city that is indeed very green, but which cannot compete internationally, for example with many cities in the United States, when it comes to the sheer number of submissions. The competition originated there, and to this day it still mobilizes particularly large numbers of participants. At the same time, there is also strong engagement worldwide: in cities such as Hong Kong, Mexico City, or Cape Town, many nature enthusiasts are inspired to take part in the City Nature Challenge year after year (screenshot taken on May 15, 2026 from the official City Nature Challenge website).

In the previous year, during the City Nature Challenge 2025, the highest number of observations were uploaded in La Paz, followed by San Antonio and Cochabamba. In terms of species richness, Cochabamba and San Antonio were also at the top, followed by Hong Kong. The largest number of participants was likewise mobilized in La Paz, closely followed by Cochabamba and San Francisco. It is particularly remarkable that La Paz has managed for several years now to inspire so many people to take part in the City Nature Challenge. All the more, it is a joy to see this success for Bolivia.

In Berlin, 382 nature enthusiasts were drawn into the friendly competition and out into nature last year. How many there were this year in the City Nature Challenge 2026 remains to be seen.

In the following, I will first report on my own observations before later taking a look at the overall results. I took my photos this weekend in Volkspark Friedrichshain as well as in Großer Tiergarten.

It is also important to note that each participating city has its own project page on iNaturalist, where all observations are collected and analyzed. The page for Berlin can be viewed here (screenshot from May 15, 2026 on iNaturalist).

On my first day of participation in the City Nature Challenge 2026, I initially focused on the plants in Volkspark Friedrichshain. I would actually have liked to photograph more birds as well, but I consciously decided not to bring my large telephoto lens—it is simply too heavy and impractical.

In addition, it was already the afternoon, a time of day when bird activity is generally lower. However, I did spot a few birds at the feeding station in the park and was able to photograph them. These included, among others, a single common wood pigeon. Overall, it was fairly quiet.

A bird that I always, really always observe in Volkspark Friedrichshain is the great tit. However, I have recently been seeing noticeably fewer of them. That surprises me a bit, because great tits are often remarkably tame and will sometimes even eat seeds directly from your hand. Normally, there are many of them in that area.

Perhaps they are currently finding better food sources elsewhere?

At least that is my assumption. Especially in winter, large numbers of great tits often gather at the bird feeding station, attracting many bird enthusiasts. In summer, however, far fewer of them can be observed there.

Furthermore, I heard the first nightingales singing in Volkspark Friedrichshain. However, I did not manage to see any of them that day. That was to change the very next day—but more on that later.

In Volkspark Friedrichshain, I also photographed a wide variety of plants to upload them later to iNaturalist. These included, for example, lesser celandine (top left), a typical early spring bloomer, as well as the beautifully purple-flowering common lilac (top right). Greater celandine (middle left) could also be found here and there. Garlic mustard is also quite common at this time of year (middle right). The purple dead-nettle (bottom left) was seemingly everywhere, as was the European stinging nettle (bottom right).

Since I mainly write about animal observations on this blog, I tend to be more reserved when it comes to my further plant observations. In addition, not all of my observations on iNaturalist have yet been identified by other nature enthusiasts. For the plants mentioned here, I am mostly confident that they have been correctly identified. However, for one of them I am still uncertain about the exact species.

If you are knowledgeable about plants, you are welcome to visit my profile on iNaturalist and help me with the identification. There you can of course also take a look at my other observations.

The next day I fortunately had time to focus on birds in a more relaxed way. I went to Berlin´s Tiergarten, as I was hoping for a high diversity of bird species on an April day. The Berlin´s Tiergarten is a large urban park that has increasingly become an important habitat for many different species. And indeed, on that Sunday I encountered numerous bird species that I was able to contribute to the City Nature Challenge 2026.

At first, I came across a female blackbird. Quick but quiet, she was moving along the ground.

But suddenly I was distracted by a loudly singing nightingale. Where was that song coming from? I stopped and tried to locate the source without disturbing the bird. My eyes scanned through the bushes, carefully checking every hiding place—but at first, without success.

And then I saw it right in front of me. How could I have possibly overlooked that nightingale?

It feels like nightingales are becoming easier to photograph from year to year. Am I simply becoming more attentive when it comes to nightingales? Are they increasing in number in Berlin while also losing some of their shyness toward humans? Or is the competition among males so strong that they expose themselves more in order to be noticed by females?

I cannot answer these questions. Perhaps the first one: I do think that with each passing year I become more attentive when it comes to birds. The longer I engage with them, the more I learn about their behavior, and my observational skills develop accordingly.

At some point I moved on. I could have listened to and watched the nightingale for longer, but singing likely already costs it enough energy. In addition, I did not want to accidentally disturb it. So I continued on in a wide arc.

Shortly afterward, I once again spotted a blackbird—this time a male blackbird.

The blackbird seemed to look at me somewhat puzzled and then quickly moved on. It appeared less shy than simply very busy—hardly surprising, given that it is mating season in spring.

Nevertheless, I continued walking. And then, a little further away, I spotted a rabbit feeding. However, it was only a single animal. Since I am no longer regularly out in the Berlin´s Tiergarten, I have particularly noticed that I see fewer wild rabbits there overall.

What has happened? Has a disease perhaps broken out? Has predation pressure from animals such as foxes or birds of prey increased? Or have changes in the park’s habitat caused the wild rabbits to retreat to other areas?

It is also possible that this is simply a misperception on my part.

Eventually, the wild rabbit noticed me, looked in my direction, but continued feeding for a while. In the end, however, it decided to run off. It was the only wild rabbit I saw that day.

After this brief encounter, I continued walking. I heard a short-toed treecreeper and a nuthatch, but did not manage to see either of them. It was also difficult to clearly identify their calls in the moment. Therefore, I was unfortunately unable to contribute any records of these two species to the City Nature Challenge 2026 at that point.

I also heard a song thrush. Each year, I look forward to its song almost as much as that of the nightingale. Fortunately, I eventually spotted one sitting on a branch.

The song thrush, however, did not stay perched on the branch for long and soon flew off again.

I continued on, passing a number of trees, when I suddenly heard a familiar song: that of the wood warbler. By now I can recognize the song of this species quite well, even though I usually only hear it in spring. However, I did not get to see it—it stayed high up in the canopy. I also did not manage to record its song. Still, I was very happy to hear it again; it was my first wood warbler of the year.

Instead, I managed to observe a great tit (top left), even though the photo was not particularly good. For the City Nature Challenge 2026, however, the identification was sufficient—the species was clearly recognizable. The same applied to the great spotted woodpecker (top right).

The Eurasian blackcaps were also already very active and vocal on this April day. I eventually managed to photograph one of them as well (bottom).

Besides the birds, I had actually also wanted to photograph a few plants. I did capture some, but overall my focus was clearly on the birds. Somehow they captivate me so much that I perceive everything else around me less intensely.

I also encountered more blackbirds and eventually a European robin. To be precise, I heard it first and did not see it at first—similar to the nightingale earlier. I scanned the branches of the tree in front of me as well as the surrounding bushes where it might be hiding. It took a moment. I stood still to avoid disturbing it.

And then I finally spotted it: clearly visible on a branch right in front of me. Why had it taken me again so long to see it?

Next to the tree there were numerous bushes. From one of them I heard singing—that had to be a warbler. I carefully searched the dense undergrowth, but it was difficult to spot the bird.

In the end I was lucky: for a brief moment, a lesser whitethroat peeked out of the bushes, and I was able to take a photo of it.

I had the warbler identified via iNaturalist, because the lesser whitethroat looks quite similar to the common whitethroat. I have already seen a common whitethroat once on the Tempelhofer Feld. In Berlin, however, I generally hear more lesser whitethroats.

Since the song in Tiergarten did not immediately remind me of a lesser whitethroat this time, I was honestly cautious with my own identification. What do you think?

At the City Nature Challenge 2026, more than 100,000 nature observers worldwide took part (2026: 106,354). In total, over 3 million observations were submitted (2026: 3,001,825), and more than 76,000 species were identified (2026: 76,422+).

Compared to the City Nature Challenge 2025, this represents around 3,400 more participants (2025: 102,945). At the same time, however, fewer observations were uploaded to iNaturalist than in the previous year: in 2025 there were still over 3.3 million observations (2025: 3,310,131), despite fewer people participating at that time.

The picture is different when it comes to identified species: here, the City Nature Challenge 2026 is ahead of the previous year. In 2025, over 73,000 species were identified (2025: 73,765), meaning that more than 2,500 additional species were identified this year.

What could be the reason for this?

According to newsletters from iNaturalist, the platform is currently increasingly encouraging users not only to upload observations, but also to participate in species identification. In line with this, there is this year—alongside the categories observations, species, and observers—for the first time a separate category for identifiers.

This could explain why, despite a lower total number of observations, more species were identified: the community seems to be participating more actively in the identification and evaluation of findings—not just in uploading new observations (screenshot from May 15, 2026 on the official City Nature Challenge website).

The cities and regions where the most people were mobilized were San Francisco, Monterrey, and Washington, D.C.—meaning that this year they were exclusively locations in North America. The highest number of observations, however, was uploaded in Ostrava in the Czech Republic, followed by San Antonio and Dallas in the United States. The most species were identified during the City Nature Challenge 2026 in Styria. San Antonio ranked second in terms of identified species, followed by Hong Kong.

The results were somewhat surprising. In previous years, cities such as La Paz and Cochabamba often ranked very highly. This year, however, fewer people there seem to have been mobilized for the City Nature Challenge 2026.

And how did Berlin perform?

Unfortunately, Berlin declined across all three categories. In the new “identifiers” category, Berlin reached a total of 762. This year, 278 nature observers took part (2025: 382), uploading a total of 20,974 observations (2025: 21,794). In total, 2,321 species were identified (2025: 2,634) (screenshot from May 15, 2026 on iNaturalist).