Chicago-area residents and businesses are being urged to take steps to protect vulnerable birds when migration alerts are issued Tuesday.
Researchers at CornellLab, along with Colorado State University and UMass Amherst, say millions of birds are expected to fly over the state of Illinois on both Tuesday and Wednesday nights.
As a result, a migration warning was issued for both nights, with residents asked to turn off all non-essential lights.
“Bright lights attract and disorient nocturnal migratory birds, potentially causing fatal collisions with buildings,” officials said.
Residents are also urged to leave cats indoors, as cats tend to hunt at night and exhausted birds have a harder time avoiding predators.
American Redstart, Swainson’s Thrush and Bay-breasted Warbler’s are among the birds expected to travel through area on Tuesday evening and into Wednesday morning.
American redstarts spend their winters in Central and South America, while bay-breasted warblers usually spend their winters in the northern forests of South America, according to experts.
Birds begin making their journeys south to their winter homes, with more than 43 million birds flying across the state of Illinois Sunday night and into Monday morning alone. Nearly 380 million birds have already flown over the state since the fall migrations began.
According to American Bird Conservancy, there are four main “flyways” of birds use to fly south during the winter, and Illinois is in the middle of the “Mississippi Flyway,” a popular route used because of ample access to lakes and rivers, as well as projections where the birds can rest on their long journeys south.
Chicago’s location on that flight path can lead to catastrophic outcomes, as tall buildings with lots of glass and interior and exterior lighting can disorient the birds and cause them to hit the buildings.
City officials have tried to assuage some of those concerns, with McCormick Place officials recently placing special films over windows to protect birds after thousands of birds crashed into the building in recent years.