Why do some animals abandon their offspring

City animals

Goodbye country life

Scientists predict: The number of animals in cities will continue to increase in the future. Because many are doing better here than in the country, says Berlin wildlife expert Derk Ehlert. The large supply of feed is decisive for this.

The large amount of open and easily accessible waste attracts foxes, swifts and raccoons to the big city. The conditions here are better than outside in the forest, in fields and meadows, where agricultural monocultures offer little food.

"We only grow one type of plant per hectare, over-fertilize the fields, and use heavy equipment to destroy habitats," says Derk Ehlert. What grows and what doesn't, is entirely in the hands of a person. This means that there is less food left for wild animals in the countryside.

New highways and railways cut their habitats more and more and reduce the area for foraging even further. The cities are also expanding, so that some animals are completely losing their rural habitat.

Hello city life

The city is diverse and offers the wild animals enough food. Full garbage cans, for example, invite you to foray. In Kassel they even have to be locked because raccoons open the bins. Allotments offer a wide range of plant-based food on the bed or compost.

And sometimes people even feed the animals extra. People feed birds in winter, and starvation is almost impossible.

A big city has a lot to offer animals not only in terms of foraging but also in terms of accommodation. There are niches to live in in parks, houses, and fallow land that are even safer than the wild.

Wild rabbits, for example, are hunted less frequently in residential areas than outside of the city: natural enemies do not get lost here, dogs are usually on a leash and a hunter only becomes active when the population is too much.

The mostly dry and warmer climate also keeps the animals in the city, where the next generation is well taken care of. Wild boars, rats, foxes, pigeons, rabbits - they all become so-called cultural successors: They live very close to people and benefit from it.

Fallow land in Berlin

Animals should live in the middle of the big city, even in the middle of the German capital? In fact, it is mainly the sections between the districts, especially the fallow land, that are so attractive to wildlife.

"Berlin is unique because of its structure," says wildlife expert Ehlert. "The city is arranged in a star shape, criss-crossed by a lot of green. It is thus possible for an animal to penetrate from the very outside to the center."

The mixture of grassland, short distances to the rubbish and quiet hiding places invites the animals. Especially in Berlin there are numerous fallow land on which they can settle undisturbed and multiply. It also has a lot to do with the history of the city. After the fall of the Wall, many old businesses were closed; What remained were abandoned halls and factory grounds.

Animals find new living space at the abandoned freight yards in the former GDR. Other cities and regions that are undergoing structural change also offer wild animals new habitats on fallow land, for example the Ruhr area.

Animals change

Life in the city is not like life in the country - and that leaves its mark. The animals react to their environment and change. If they live close to humans, they lose their natural shyness. A return to the wilderness is hardly possible for the second generation.

Because the animals only know life in the city and would not survive in other surroundings besides their natural predators. There are foxes that have made themselves at home in parks and no longer leave their territory. If they were stunned and taken into the wild, they would be back in place the next day.

Birds also change their behavior: great tits and nightingales sing louder and more shrill in the city, as ornithologists have discovered. They suspect the animals do this to sing over the city noise. Some robins become nocturnal to avoid contact with humans.

And starlings and blackbirds suddenly chirp cellphone melodies. Scientists do not agree on whether urban animals will still be able to reproduce with their conspecifics in the wild in the future. Ornithologists, however, predict the emergence of new species that specialize in urban life in the long term.

Animal immigrants

The city is not only home to animals that have come from the countryside. Again and again one hears of escaped exotic animals who do not come from our latitudes. In September 2010, for example, a kangaroo that had been torn away made headlines in Hamburg and the police made every effort to recapture it.

It turned out that the owner was missing a second one too. Would the marsupials have a chance to survive? The story is very reminiscent of the spread of the raccoon in Germany.

In the 1930s, two pairs of raccoons lived in Germany: one was released on the Edersee near Kassel, the other had run away in Berlin. Today, decades later, the animals, which originally came from North America, have become a real nuisance. Raccoons have found their niches in Germany and are multiplying rapidly.

"This is a sign that they are doing well with us and that the range of feed is excellent," says Derk Ehlert. "We can do little there. Only scarce feed resources or diseases could reduce the population."

Author: Claudia Kynast