A significant number of birds are expected to travel through the Chicago area on Tuesday night, prompting a migration alert.
Birdcast, a website dedicated to tracking migrating birds and predicting migration patterns, reported more than 28,000 birds will be in the skies per square kilometer throughout the night.
According to experts, the greatest traffic times for migrating birds typically occur between 11 p.m. and 6 a.m., when hundreds of thousands of birds cross over the Chicago area on highly trafficked evenings. During such periods, residents are asked to turn off all non-essential lighting.
Bright lights can attract and disorient migrating birds and can potentially cause fatal collisions, according to Birdcast.
Since 1995, Chicago has adhered to a “Lights Out” program each migration season; it encourages the owners and managers of tall buildings to turn off or dim decorative lights. Tenants on buildings’ upper floors are asked to turn out lights or draw blinds after 11 p.m. from Aug. 15 to Nov. 15 for the fall migration and from March 15 to June 15 during the spring.
The McCormick Place, one of the most dangerous buildings along the lakeshore for birds, installed 3.6 million dots on its windows to help prevent bird strikes during the summer of 2024. The program has drastically reduced the number of bird strikes at the building, officials previously said.
During the fall migration, most birds typically pass through the U.S. from early September to October. Each spring, bird migrations peak over Illinois in mid-to-late May.