A new study has named Chicago as the most dangerous city in America for migrating birds, and a group is hoping to bring about changes to help reduce the number of birds that die while flying through the city.
According to the study, conducted by Cornell University, Chicago tops the list due to a variety of factors, including the bright illumination of its skyline and the amount of glass on buildings, which can reflect the sky or other habitats and cause confusion and disorientation in birds.
“(The study) confirms what we’ve always felt: that there are a lot of hazards in Chicago,” Annette Prince of the Chicago Bird Collision Monitors said.
According to data released by the group, tens of thousands of birds are killed in Chicago every year, while over 6,000 birds a year are killed within a one-square mile area of the downtown area.
The group is now part of an effort to circulate a petition that would call for a “Lights Out” program in the downtown area. With more than 40,000 signatures, the petition calls for lights that point downward, and for businesses and residences to dim lobby lights at night to make them less visible to migrating birds.
“We want the very bright top lights to go out,” Prince said.
A similar city ordinance, called the “Bird Friendly Design Ordinance,” was introduced in the Chicago City Council earlier this year. The bill would aim to protect native and migratory birds that fly through Chicago.
“We would like it to be spread throughout the Chicago area, as well as established as an ordinance,” Prince said.
Millions of birds migrate through the Chicago area every year, making it one of the most highly trafficked areas of the country. While coastal areas tend to only see birds migrate through once a year, the Chicago-area sees migrations in both directions due to its centralized location in the United States.
That factor, as well as the heavy light pollution that the city’s buildings give off, both make a serious impact on migratory patterns and lead to thousands of bird strikes every year.
Artificial light tends of draw in migratory birds, according to the Cornell study, and birds drawn in by those lights can call in other birds, leading to mass bird strikes. The light can also disorient birds, causing them to expend more energy in trying to find their way around buildings.
Glass can also pose a threat to birds, as it can reflect the sky. Birds will also try to fly through glass if they can see the sky on the other side, according to the Smithsonian Magazine.
The study that tagged Chicago as the most dangerous city for migratory birds took into account 20 years of satellite data showing light pollution and weather radar, which helped determine the density of migrating birds across the country.
According to the Audobon Society, there is something that homeowners can do to help. If you live in an area that experiences high numbers of migrating birds, you’re encouraged to make sure your exterior lights are pointed downward, which can help prevent birds from being attracted to, or disoriented by, the lighting.