Modern cities are literally crowded with high-rise buildings, so it is extremely unsafe for birds to fly in such an area - they can easily crash against any structure. Researchers from the University of Michigan found that birds especially risk their lives at night, especially if they coordinate the movement of the flock with the help of singing. The reason for this is the artificial lighting of cities - it confuses the birds, and they doom each other to certain death.
The researchers came to this conclusion after studying bird collision statistics collected by staff at the Field Museum of Natural History in Chicago since 1978. In addition to this knowledge base, researchers had access to more relevant information collected by volunteers. So, only in Cleveland and Chicago during all this time because of the night collision with buildings, about 70,000 birds have died.
According to biologist Benjamin Winger, mortality is directly related to the way people light cities. Night flights probably somehow make it easier for the birds to make collective decisions, but the city lights are confusing. Individuals flying at high speed, with their singing, can call their relatives behind them, which is why, instead of one death, several happen at once. It is noteworthy that previous studies have shown that birds "communicate" much more often inside illuminated cities than in open areas.
Because of all this, urban lighting can be considered another anthropogenic factor to look out for. Cleveland and Chicago are of particular interest to researchers because they are along the north-south route of migratory birds. To identify more precise reasons for the disorientation of birds, scientists intend to continue research - perhaps new discoveries will help them solve the problem.
Ramis Ganiev