Avian Enthusiasts Work to Mitigate Risks of High-Rises for Migrating Birds in Chicago

At dawn in downtown Chicago, Annette Prince, armed with a neon-green net, searches for injured birds. She soon finds a small yellow bird on the pavement. It doesn't fly away, so she carefully nets it and places it in a paper bag, noting the date, time, and location. "This is a Nashville warbler," says Prince, director of the Chicago Bird Collision Monitors. "He must only weigh about two pennies. He's squinting his eyes because his head hurts."

Bird collisions with buildings are a frequent occurrence during migration seasons in Chicago. The Chicago Bird Collision Monitors often encounter such incidents as birds fly into homes and skyscrapers. Last autumn, 1,000 migrating birds perished in one night after hitting the glass facade of McCormick Place, a convention centre by Lake Michigan. This fall, the centre introduced bird-safe window film on one of its glass structures.

Efforts to Reduce Bird Collisions

The USD 1.2 million project at McCormick Place involved applying tiny dots to the Lakeside Centre building's exterior glass, covering an area equivalent to two football fields. Doug Stotz from the Field Museum hopes this initiative will succeed. He estimates that only about 20 birds have died from collisions with the convention centre's glass this fall, which is promising.

"We don't have a lot of data since this just started this fall, but at this point, it looks like it's made a huge difference," Stotz said. Meanwhile, volunteers like Prince document bird casualties and injuries downtown to understand better and address the issue.

Rescue and Rehabilitation Efforts

Injured birds are taken to wildlife rehabilitation centres such as DuPage Wildlife Conservation Centre in Illinois for recovery. On a recent morning, veterinarian Darcy Stephenson examined a yellow-bellied sapsucker with a broken ulna due to a window collision. The centre receives about 10,000 animals annually, with 65% being birds.

During peak migration periods in autumn, hundreds of birds may arrive daily at the centre due to window collisions. Sarah Reich, head veterinarian at DuPage, notes that many birds survive and return to the wild after treatment. "Fractures heal very quickly in these guys for shoulder fractures," she said.

Challenges and Successes in Rehabilitation

Rehabilitation involves flight testing and thorough physical exams before release. Reich mentions that staff get excited about successfully treating challenging cases or injuries they've never managed before. "It's exciting to be able to get these guys back out into the wild," she added.

Efforts continue to educate officials and improve building designs and lighting to reduce bird collision deaths in Chicago and globally. The city lies on a major migratory path through the United States, compounded by artificial lighting that confuses birds traveling at night.

Dead birds are often preserved for scientific research at institutions like Chicago's Field Museum of Natural History. These efforts aim to mitigate the impact of urban environments on migrating bird populations.