Nearly 1,000 Migrating Songbirds Tragically Perish in Collision with Windows at Chicago Exhibition Hall

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David Willard, who has dedicated four decades to inspecting the premises of Chicago’s lakefront exhibition center for deceased birds, made a grim discovery on Thursday morning. The grounds were strewn with the lifeless bodies of songbirds, so numerous that they resembled a macabre carpet.

Close to 1,000 songbirds met their untimely demise during the night after colliding with the windows of the McCormick Place Lakeside Center. Avian experts attribute this tragedy to a lethal convergence of factors: ideal migration conditions, rainfall, and the exhibition hall’s unique design with well-lit interiors and walls lined with windows.

“It was akin to a haunting tapestry of avian casualties at the windows,” recounted Willard, a retired manager of the bird division at the Chicago Field Museum. His responsibilities included overseeing, preserving, and cataloging the museum’s extensive collection of 500,000 bird specimens, as well as monitoring bird strikes as part of migration research.

Under normal circumstances, the count of deceased birds would range from zero to 15 on any given night. This incident, however, stands as a shocking outlier in the 40-year history of observations at McCormick Place. Willard remarked, “In 40 years of tracking events at McCormick, we’ve never encountered anything remotely on this scale.”

Researchers estimate that window strikes claim the lives of hundreds of millions of birds in the United States annually. In a 2014 study conducted by scientists from the Smithsonian Conservation Biology Institute and the U.S. Fish and Wildlife Service, the number was estimated to fall between 365 million and 988 million birds per year.

Window strikes are a pervasive issue in almost every major U.S. city. Birds often fail to perceive clear or reflective glass as a barrier, resulting in fatal collisions when they attempt to reach the perceived foliage or plants beyond the glass.

This phenomenon, known as fatal light attraction, has manifested in various urban centers. For instance, in 2017, nearly 400 passerines became disoriented in the floodlights of a Galveston, Texas skyscraper, leading to their tragic deaths in window collisions.

Matt Igleski, the Executive Director of the Chicago Audubon Society, lamented, “Unfortunately, it is really common. We see this in pretty much every major city during spring and fall migration. This (the window strikes at McCormick Place) was a very catastrophic single event, but when you add it all up (across the country), it’s always like that.”

The conditions were conducive to a massive southern migration of songbirds over Chicago on the preceding Wednesday evening, as explained by Stan Temple, a retired professor of wildlife ecology and an avian expert from the University of Wisconsin-Madison. These small songbirds typically feed during the day and migrate at night to avoid turbulence and predators. However, they had been delayed due to unseasonably warm southern winds in September. When a front finally swept south, providing a tailwind, thousands of birds took flight simultaneously.

These birds followed the Lake Michigan shoreline, ultimately encountering a maze of illuminated structures, as Temple pointed out. Subsequent pre-dawn rain forced them to descend to lower altitudes, where they found the lights of McCormick Place still on. The result, according to the Field Museum’s tally, was 964 bird fatalities at the center. This figure is nearly 700 more than the highest previous count over the past four decades. Among the casualties, 33 different bird species were identified, with a majority being palm and yellow-rumped warblers.

Preventing window strikes and fatal light attraction is relatively straightforward, asserts Anna Pidgeon, an avian ecologist at the University of Wisconsin-Madison. Building managers can mitigate the issue by dimming their lights, and architects can incorporate markings in the glass to make it more visible to birds. Additionally, individuals can install screens, paint windows, or affix decals to the glass to reduce bird collisions.

Several cities, including New York, Boston, San Diego, Dallas, and Miami, have joined the National Audubon Society’s “Lights Out” program. This initiative encourages urban centers to turn off or reduce lights during migration months. Chicago is also part of this program, but its implementation of bird safety measures in new buildings is still pending, despite the passing of an ordinance in 2020. Notably, McCormick Place, constructed in 1959, poses unique challenges due to its architecture and proximity to the lakefront.

Cynthia McCafferty, a spokesperson for McCormick Place, affirmed the center’s participation in “Lights Out” and stated that interior lighting is typically turned off when the building is unoccupied. Nevertheless, during events, the lights have been operational. McCafferty could not confirm the timing of the window strikes or whether the center was occupied at the time.

Reflecting on this tragic event, Willard remarked, “It’s an odd building… When it was built, people weren’t thinking about bird safety. They still aren’t in most architecture. It’s right on the lakefront. There are many nights when it’s lit up. People are describing the whole night of migration as part of a once-in-a-lifetime thing … (but) this still is an unacceptable intrusion by humans and their architecture. Just terribly sad and dramatic.”

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[Note: The story has been updated to correct the name of the exhibition center to McCormick Place, not McCormick Center.]

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More about Bird Mortality

• Chicago Tribune Article
• Smithsonian Conservation Biology Institute
• National Audubon Society’s Lights Out Program
• University of Wisconsin-Madison Department of Forest and Wildlife Ecology
• Chicago Field Museum