Almost 1,000 Birds Died in One Night From Striking a Chicago Building

Another 1,000 were killed in window collisions across the downtown area, amid calls for more bird-friendly architecture and reduced light pollution     

In an average year, about 1,000 to 2,000 migratory birds die from striking a lakeside Chicago convention center, reports Clare Marie Schneider for NPR.

But on one single night last week, at least 961 birds were killed after crashing into the building’s glass exterior.

“It was just like a carpet of dead birds at the windows there,” David Willard, a retired bird division collections manager at the Chicago Field Museum, tells Todd Richmond of the Associated Press.

“A normal night would be zero to 15 [dead] birds. It was just kind of a shocking outlier to what we’ve experienced,” he tells the news service. Museum volunteers have tracked bird deaths at the building for four decades, and they say no other single night has been so deadly.

With its mostly glass facade and location beside Lake Michigan, the building, called McCormick Place Lakeside Center, is a well-known bird hazard in the Windy City. Volunteers and researchers from the Field Museum visit the site daily during the spring and fall migration seasons to look for and collect bird carcasses, writes Amanda Holpuch for the New York Times. The center’s previous record was 200 bird fatalities in one night, per the publication.

Most birds migrate by night, relying on the stars for navigation—so artificial light emanating from buildings can be highly disorienting. The animals do not recognize windows as solid objects, and reflections on the glass can look like a continuation of the sky or the habitat that surrounds a building.

Chicago has been named one of the deadliest cities for birds because of its high light pollution and its placement along one of the continent’s most trafficked migratory flight paths, known as the Mississippi Flyway. Beyond the avian carcasses collected at McCormick Place last Wednesday, volunteers found an additional roughly 1,000 dead birds across the rest of the downtown area.