The City Nature Challenge in Berlin

The City Nature Challenge is a global competition which takes place every year on one long weekend. Several cities around the globe participate in this competition. Berlin was one of these cities in 2019. During the City Nature Challenge every participating city asked its citizens between the 26th and 29th of April to record every nature observation. Berlin could count on many nature enthusiasts during that weekend. In this blog entry I will tell you more about the City Nature Challenge in Berlin and why you will read more about citizen science in future here on this blog.

What is the City Nature Challenge?

In 2019 the City Nature Challenge took place between the 26th and 29th of April. The City Nature Challenge was organized by each participating city through an institution. The Museum für Naturkunde was in charge of this competition in Berlin. During that long weekend in April the museum offered several presentations, nature walks or other events to their participants. I went to the event NachtiGala in the Museum für Naturkunde, accompanied a hedgehog researcher on his monitoring walk and listened to a presentation about bats (further below I will tell more about all this).

I read about the City Nature Challenge on the citizen science platform iNaturalist. Although the City Nature Challenge is a competition, it’s about more than just winning. It’s rather about exploring nature and improve knowledge about plant and animal species. Every participant is encouraged to contribute to a worldwide research project to know more about the distribution of different species. Thus, the City Nature Challenge is not only a competition, but also a worldwide citizen science project.

Of course, I was encouraged to participate in the City Nature Challenge on that weekend in April. I went to a park close to my flat and collected some nature observations by taking photographs or recording bird songs. The City Nature Challenge was also a reason for me to get to know the app Naturblick, as it was only possible to participate in the City Nature Challenge in Berlin via this app (I will tell you more about this app in the paragraph after next).

On that weekend I observed especially many blackbirds (Turdus merula) and great tits (Parus major).

I also saw many blackcaps (Sylvia atricapilla) and squirrels (Sciurus vulgaris).

In total, 596 different animal and plant species were found during the City Nature Challenge in Berlin on that weekend.

Why citizen science?

The City Nature Challenge was not only a reason for me to learn more about the app Naturblick, but also to dig more into the topic citizen science. I had the idea long before to incorporate this topic more into this blog. I came across citizen science for the first time on my three month stay in South Africa. During my time in South Africa I joined citizen science projects by contributing, for example, photographs of whales and dolphins and other environmental information to several projects. I also helped collecting egg cases of sharks and writing down every sighting of a shark. Since then I thought again and again about citizen science and how I could connect this topic with my travels.

On my two-month journey through the south of Brazil, I tried to record as many animal observations as possible to share them on the citizen science platform iNaturalist. On the one hand, I wanted to share all my animal observations with others (I thought maybe it is helpful for some people?), and on the other hand, I wanted to learn more about Brazil’s wildlife. The platform iNaturalist was a great possibility for me to let identify several animal species by experts or nature enthusiasts, respectively. In this way I learned a lot about many animals in Brazil.

However, why citizen science? For me there are three reasons why I think citizen science is important and why you will read more about this topic here on this blog in future blog entries.

Firstly, I think it is just a great thing to participate in a worldwide research project. I think, the more we are, the better we understand the distribution of species. I’m convinced that the more we know, the better we can protect all those different animal and plant species.

Secondly, in my opinion citizen science is a great way to improve knowledge about species. I think that citizen science encourages people to stay curious.

And thirdly, exploring and discover new species is just fun. You learn more things about different animal and plant species, but you also have to be outside in nature. I personally enjoy looking for animals in the parks, in the forests or anywhere else. Sometimes, you might even have a very special encounter. I had one of this special encounter, for example, in Brazil when I observed the world’s largest fly species. I found this fly in the Atlantic Forest in Minas Gerais close to Caratinga and Ipanema. As I’m not an insect specialists, I was not aware of this in the forest. Only on iNaturalist an insect expert told me that. I’m also always very happy when I can make the first contribution of an animal species on a citizen science platform like on iNaturalist. This was the case, for example, for the crested capuchins which I found in the southeast of Brazil.

The City Nature Challenge in Berlin

The app Naturblick

As mentioned above, it was only possible to participate in the City Nature Challenge in Berlin via the app Naturblick. Therefore, I want to write more about this app in the following paragraph. The app was created by people from the Museum für Naturkunde in Berlin. During the City Nature Challenge I realized that the app is useful not only during the competition, but also afterwards.

So far, I shared my nature observations like the ones in Brazil on iNaturalist by taking photographs with my reflex camera and uploading them on their website. iNaturalist also has created an app for mobile phones or tablets. However, as I do not enjoy taking photographs with mobile phones or tablets, I haven’t used it until now.

During the City Nature Challenge I was more or less forced to use only the app Naturblick, as there is no corresponding website to upload nature observations. Therefore, I had to take photographs of all my nature observations with my tablet.

On the front page of the app you will find all your fieldnotes (German: “Feldbuch”) with all your nature observations. Be it a photo or be it a recording. Every nature observation is automatically added to the fieldnotes section. If you do not have internet on your mobile phone or tablet while you are outside, it is possible to identify all observations afterwards to contribute them to the City Nature Challenge.

Another section of the Naturblick app is the species descriptions (German: “Art-Portraits”) with 557 different animal and plant species in total. Among them are 13 amphibians, 24 bees, wasps and others, 315 herbs and wild flowers, 42 leaf trees and ginkgo, 5 reptiles, 29 butterflies, 29 mammals and 100 birds.

There are three ways to identify animals and plants via the app. I used especially the function “Record bird song” (German: “Vogelstimme aufnehmen”). As it was so difficult to photograph birds with my tablet, I only recorded birds by their bird songs. I tried this function and was immediately convinced about the capability of the app. The Naturblick app identified correctly almost all bird songs.

In some occasions I tried to record a bird song of one bird species, but some other birds were singing in the background. In this case, of course, the app had more difficulties to identify correctly the target bird.

During the City Nature Challenge I tried to take photographs of some house sparrows and wood pigeons with the app Naturblick. However, I was not successful with this. Although these birds were not that shy, it was too difficult to get a useful photo of them. It was impossible for the app to identify the birds (but of course you can add the correct identification by yourself).

In the first moment it was not that easy for me where and how to take a photograph with the app. If you want to take a photograph with the app, you have to enter the section with the fieldnotes and click on the plus sign on the right. In this way you can also record audios.

There is another function in the app which I really like. The function’s name is “Photographing plants” (German: “Pflanze fotografieren”). If you click on this function, the camera of the app automatically opens. With this function it is possible to identify the plant with the app (you need Internet for that). I was very impressed by the capability of the app. However, I have to admit, that I wouldn’t trust blindly an app with respect to the identification of animals or plants. I personally prefer to control the results of the app. Furthermore, if you do not know much about plants, in my opinion, the photographs in the app are not enough to identify a species. If you have internet access while you are outside, you will find further information. The app will lead you to the corresponding and informative websites. If you do not have internet access, you can check this information later.

The third function of the app is “Choose characteristics” (German: “Merkmale auswählen”). This function will lead you to the 557 different animal and plant species of the species portraits. With this function you will be able to identify a species step by step.

If you need more information of a species (you need again internet for that), the app will lead to an Open Nature Guide (German: “Offener Naturführer”) which will further assist you in the identification of aspecies.

The event NachtiGala

Starting point of the City Nature Challenge in Berlin was the Museum für Naturkunde. One of its current citizen science projects is about the nightingale. The name of the project is “Forschungsfall Nachtigall”. At the start of the City Nature Challenge and the nightingale season, respectively, the Museum für Naturkunde organized the NachtiGala in the museum. Of course, I visited the museum on that evening.

The program of the NachtiGala was very interesting. All visitors could not only learn more about the nightingale itself, but also more about the citizen science project of the nightingale in Berlin. An artistic performance and discussions on the stage about citizen science, science communication and knowledge about species contributed to a very diverse program on that evening. They also discussed about how citizen science could connect children and young people in schools with nature. Furthermore, all visitors could ask researchers more about the nightingale. Do males and females of the nightingale sing? How do the nightingale songs differ between day and night? And how is the song of a nightingale structured? On that evening you could meet many nightingale experts to find an answer to all these questions. You could also hear more about how everyone can participate in the citizen science project. As the aim of the project is not only to inform, but also to motivate people to actively engage in the project, all visitors of the museum could share their anecdotes about the nightingale in Berlin. In general, it was a very interesting and nice evening in the Museum für Naturkunde.

Monitoring of hedgehogs in the Treptower Park

During the City Nature Challenge it was possible to join several excursions and presentation or other events. On one evening I went to the Treptower Park in Berlin to help searching for hedgehogs in the park. On this evening I learned more about hedgehogs in Berlin.

We were a group of about 10 people. Equipped with torches we walked through the Treptower Park trying our best to find hedgehogs. In total, we met just one hedgehog on this evening at the end of April. However, this was actually not a big surprise. Apparently, one year ago it was similar. They had found just one hedgehog one year before. Maybe the population of hedgehogs in Berlin is decreasing? They do not know that for sure yet. However, they know that the population of hedgehogs in England is in decline. And in Germany? They don’t know yet, but researchers try to find this out by monitoring hedgehogs in the parks of Berlin. They use all data in statistical models to calculate or estimate, respectively, the number of hedgehogs in Berlin. For example, if they encounter an hedgehog on one day and the same hedgehog on the following day, they assume a smaller population. If they find two different hedgehogs on two subsequent days in the same park, the whole populations in Berlin might be larger.

On that evening in the Treptower Park, the researcher of the project also took some saliva samples of the hedgehog. They try to find out more about the genetic relatedness of hedgehogs in Berlin. Furthermore, they can investigate with these saliva samples, if there are barriers for hedgehogs that prevent genetic exchange. After collecting some saliva samples, the researcher also weighed the hedgehog and attached some tags to the animal to identify this individual animal again next time.

I also learned that global warming is affecting hedgehogs. If the climate is warmer, hedgehogs might wake up from hibernation during a warm winter. This could negatively influence the energy balance of hedgehogs.

Presentation about bats

During the City Nature Challenge I listened to one presentation about bats in Berlin. With 18 different bat species, Berlin is not only the capital of Germany, but also the capital of bats. In Berlin there are many common pipistrelles, mountain noctule bats or Natterer’s bats.

The presentation was about how we can help bats in Berlin and which threats bats in Berlin are exposed to. Bats need a structurally diverse habitat. They prefer dead trees with holes and do not like clean gardens where they cannot find any hiding places. Maybe this is one reason why bats like Berlin? In contrast, in Brandenburg they find mostly farmland. As bats do not find many hiding places on farmland, bats avoid these areas. Another threat for bats is the use of herbicides like Roundup. The use of herbicides kills many insects, and thus, less food is available for bats. One more threat for bats is the reconstruction of buildings. If an expertise on environmental matters was not done in detail, they might cement in bats in the buildings.

After the presentation we went to the park Bürgerpark Pankow to look for bats. We encountered many bats on this evening, however, only one species: common pipistrelles. By the way, this bat species is the most common species among the bats in Berlin. Luckily, on that evening it was not that cold and we could see many bats, because if it is too cold, bats do not come out of their hiding places. Ideally, it should be more than 10°C. Only during a long period of cold and rainy days, bats might come out of their hiding places to hunt insects.

Bats and hedgehogs have one thing in common: they suffer from global warming. For bats it is energetically disadvantageous, too, when winters are warmer than usual as they might wake up.

The winners of the City Nature Challenge

In total, 159 cities worldwide participated in the City Nature Challenge in 2019. With more than 33.000 nature observers, the number of participants has more than doubled when compared to 2018. Overall, all worldwide participants together contributed more than 32.000 different animal and plant species and almost 920.000 nature observations.

Winners were found in three categories: Observations, species, and people.

In the first category with over 53.000 observations, Cape Town in South Africa was the winner. La Paz in Bolivia with almost 47.000 and San Diego in the US with over 38.000 observations reached the second and third place, respectively. Berlin obtained the 63th place with 3003 observations (remember: 159 cities participated).

In the second category Cape Town in South Africa won again with 4588 animal and plant species followed by Hong Kong in China with 3596 and Houston in the US with 3367 species. Berlin reached the 67th place in this category with 596 different plant and animal species found during that long weekend in April.

Most people participated in San Francisco in the US where 1927 nature observers contributed their observations to the City Nature Challenge. On the second place is another city from the US: Los Angeles with 1555 people. Laz Paz in Bolivia reached with 1500 participants the third place. As 732 people participated in the City Nature Challenge in the German capital, Berlin obtained the 15th place. By the way, no other European city could encourage so many people for the City Nature Challenge like Berlin. I also want to mention here, that Berlin participated in the City Nature Challenge this year for the first time.

The citizen science platform iNaturalist summarized the results of the City Nature Challenge in an article.

Have you already participated in a citizen science project? If yes, let me know more about it. If you have participated at the City Nature Challenge, which animals or plants did you see? Did you encounter any special species?