Reduce light pollution, essential to save migratory birds

On the morning of October 5, the glass building of the Convention Center Chicago appeared surrounded by small dead songbirds. Another episode of massive collision that confirmed with facts what a study today confirms: light pollution must be reduced to save birds.

The magazine Nature Communications today publishes the largest analysis carried out to date on the impact of artificial light on birds, after episodes such as the one mentioned in Chicago – in which volunteers from its Museum of Natural History collected up to 946 dead specimens – are becoming more common.

The study, led by the University of Colorado, has compared more than 10 million observations from weather radars with landscape data and the diagnosis is clear: light pollution is the second cause of mortality for migratory birds.

“Migration is a risky stage in the lives of birds, which usually travel hundreds or thousands of kilometers, sometimes burning half their body mass along the way. Finding a good place to rest and feed is essential for migratory birds to survive and thrive once they reach their destination,” underlines Kyle Horton, a biologist at Colorado State University.

Artificial light becomes the main indicator of where to land for birds, which usually migrate at night, and at the same time an ‘ecological trap’, since it causes collisions and attracts them to cities that are not safe stopping places. due to problems such as poor air quality or the abundance of predators.

Researchers suggest that lowering the brightness, softening the color of lights, or including decals with dots or grid lines can help prevent collisions by revealing the barrier to birds.

For its part, this study has provided the first continental-scale maps of the ‘hot spots’ in bird migration in the United States, so that conservation plans and addressing light pollution can be established from them.