Many bird species take advantage of the darkness of night to fly during their migration. in spring and autumn, but also during the non-migratory seasons. A new study that focuses on the Americas but applies equally to Europe shows that increased levels of light pollution are stunning these animals.
Light attracts and disorientates birds, they often cause not only injuries, but also death when they collide with buildings. For this reason, birds try to avoid light to a large extent during the breeding season, but also at other times of the year.
However, during migration, birds travel wide ranges, including: populated areas that have higher levels of light pollution and cannot always bypass these areas. Also, in regions such as the southeastern United States, Mexico, and Central America that are considered important migration corridors, these levels have increased to 16% of the land surface over the past two decades.
Only 7% of the continental land area of the Americas has reduced light pollution levels, thanks to declining populations and urban scorch in regions such as the northeastern United States, for example, according to a new study published in the Journal. ecosphere.
For scientists at the Cornell Laboratory of Ornithology and Colorado State University this trend poses a real threat to night-flying birds during spring and autumn migration. and even in non-migration seasons.
“The evidence that nocturnal migratory birds are experiencing increased levels of light pollution in these areas is alarming,” says the lead author. Frank La SorteFrom the Cornell Laboratory quoted by the SINC Agency.
Turn off the lights during transitions
The study used data from eBird, a Cornell Labs citizen science program, where volunteer birdwatchers input their observations from anywhere in the world to create weekly estimates of the birds’ relative abundance. 42 species were included in the study.
The authors compared these abundance data with 12-month satellite measurements of light pollution collected over a 22-year period.
The scientists found that all the species studied were found in areas with increased levels of light pollution. The greatest increases occurred during migration, particularly for birds migrating through Central America. The weakest increases were seen in birds spending the summer breeding season in the northeastern United States.
“Adverse light pollution trends in Central America, particularly in the spring, and start programs Lights Out (‘lights out’) in transitional periods Kyle Horton of Colorado State University and co-author of the study, Kyle Horton,
On the other hand, the researcher suggests doing the same with light pollution trends in the southeastern United States and Central America during the summer breeding season. non-breeding winter. “This will yield the greatest benefits outside of migration periods,” he continues.
Through this work, scientists can better determine where and when birds will encounter current or increased light pollution. Therefore, they hope that more effective efforts will be made to reduce the risk of these animals and increase their survival.
Reference work: https://esajournals.onlinelibrary.wiley.com/doi/full/10.1002/ecs2.3994