Wild nature | Berlin's biodiversity: Nightingales, otters, and beavers return

"If you listen carefully now, you'll be able to recognize the nightingale's song!" Derk Ehlert holds his finger to his lips and stares intently from the Spree River into Treptower Park. The wildlife expert from the Senate Department for the Environment is aboard the "Spree-Comtess" and is telling around 300 visitors about the diverse animal life in the capital . It's the opening cruise of the Long Day of Urban Nature, organized by the Berlin Nature Conservation Foundation. On Saturday and Sunday, 500 events took place at 120 locations in Berlin, highlighting the biodiversity of Berlin's flora and fauna.

The end of April is the best time to hear the nightingales sing, says Ehlert. Then they woo the attention of the females with long, complicated songs. Now, you only hear short verses – that's the singing lesson for the newly hatched birds. "When I hear that, I know immediately: That's a male and he has offspring, so it's a successful season. It'll be back next year." Treptower Park is home to particularly large numbers of these songbirds, says Ehlert. Berlin generally boasts high nightingale numbers. "No other city has as many nightingales."

But these birds aren't the only ones feeling at home in the capital. Great gulls and cormorants perch on a jetty in the Spree River near the Osthafen harbor. Swifts, hooded crows, buzzards, greylag geese, and great egrets can also be seen on the one-and-a-half-hour Spree cruise from the Märkisches Ufer at the Jannowitzbrücke S-Bahn station to Plänterwald and back again. Wildlife expert Ehlert provides information on the species spotted. Swifts, for example, are distributed throughout the city as building nesters and flutter through the air prolifically: they can cover 150,000 kilometers in a year, says Ehlert. "And they weigh just 50 grams."

"If they learn to hunt here, they'll stay in the city. Berlin hawks are loyal to their location."

Derk Ehlert Wildlife expert of the Senate Environment Administration

Goshawks are among the birds particularly adapted to urban conditions. With 120 breeding pairs, Berlin has more of them than any other city in Europe, says the expert. They catch pigeons – a total of around 10,000 a year – and have adapted their hunting behavior to the city. "Urban goshawks are surprise hunters," says Ehlert. They fly from backyard to backyard and suddenly drop down in the hope of encountering a pigeon, which then has little chance of escape. This is a different hunting behavior than in the countryside, which is why the goshawks that grew up here repeatedly return to the big cities to breed. "Once they learn to hunt here, they stay in the city. Berlin's goshawks are loyal to their location."

Preserving green spaces is important for species conservation in the capital. Currently, 40 percent of Berlin is green space, and approximately 17 to 18 percent of the state's land area is protected, says Ehlert. However, the global extinction of species is also making itself felt in the capital, says Stefan Richter, Managing Director of the Nature Conservation Foundation. He remains optimistic nonetheless: "We see that species conservation and the restoration of areas are effective." This can be seen, for example, in the fact that some species are re-establishing themselves in Berlin that previously hadn't been found there for a long time. Beavers and otters, for example, are back in the capital, and numerous insect species are also being rediscovered – Richter mentions the lesser great capricorn beetle, for example. "They're back because we're renaturing."

The fact that numerous insect species have been rediscovered, especially in recent years, is primarily thanks to the committed urban community, says Derk Ehlert. Since 2018, the Nature Conservation Foundation's "Species Finder" has been in existence – a citizen science project. Those interested in nature conservation can enter their finds – in the garden, on the balcony, or in the grass verge on the street – into a database. For example, in 2024, the Oak Orb Moth was found in Berlin for the first time since 1986. And the Glossy Black Jewel Beetle, considered extinct in the capital for 100 years, was discovered. Since 2018, over 70,000 reports of approximately 2,900 species have been received.

Ehlert is enthusiastic about the project. "Wherever we participate, whatever we identify with, we also want to protect," he told "nd" after the Spree cruise. He believes that the biodiversity of urban nature is a vital resource for the lives of Berliners. Therefore, it is particularly important to him that residents also take action to preserve it. "The urban community is responsible for its own survival," says Ehlert.