Funding From the Leon Levy Foundation Finds That Artificial Light Makes Birds Fly Into Buildings at Night
The new analysis of a 40-year record of more than 70,000 nighttime songbird collisions in Chicago and Cleveland suggests that birds disoriented by artificial light from illuminated buildings at night send out flight calls that may lure other nearby birds to their death.
“Nocturnal flight calls likely evolved to facilitate collective decision-making among birds during navigation, but this same social behavior may now exacerbate vulnerability to a widespread anthropogenic disturbance: artificial light from buildings,” says first author Benjamin Winger, an assistant professor in the ecology and evolutionary department at the University of Michigan and an assistant curator at the Museum of Zoology. The study relies on bird-collision data Field Museum researchers collected in Chicago starting in 1978 and, more recently, data volunteer groups in Chicago and Cleveland collected.
Although the collision-monitoring efforts researchers cite in this study have led directly to reductions in light pollution in Chicago in recent years, the new findings show that more needs to be done, according to the paper’s authors.
“Our results underscore the critical importance for bird conservation of reducing artificial light at night from buildings and other structures during migratory periods,” they write.
In addition to conducting a broad regional analysis of collision frequencies, the researchers analyzed data from Chicago’s lakefront convention center, which is a hazard to migratory birds. They found that when people left more lights on at night during migration, more birds collided with the convention center and died...