When worlds collide

Response to migration mortality event offers a sliver of hope.

Of all the ways humanity has altered the environment, placing large buildings at the center of an ancient migratory flyway has to be one of the more pernicious ones. For millennia, species like Yellow-rumped and Palm Warblers have nested in the far north and flown south for the winter to places like Florida, the Caribbean, and even Central America. The birds streaming south utilize the shorelines of the Great Lakes as migratory corridors, in our case funneling along the western shore of Lake Michigan. 

But when they get to Milwaukee and later Chicago, they encounter large urban areas laden with obstacles. As much as popular migrant traps—the tiny green spaces amid the development—delight us, they are also a symptom of the broader problems we’ve caused with our sprawling cities. There just aren’t many places for the birds to land and refuel. 

Bird movements are driven by the mysterious life force of zugunruhe, the migratory restlessness period and an internal cue that it is time to take off for warmer climes. Recent weather patterns kept birds to the north of us—late September and early October were unusually warm. Southerly winds and high pressure resulted in a migratory holding pattern. There was a lot of pent-up zugunruhe. 

The dam broke when the winds finally shifted on Thursday, sending birds south in a torrent that some described as the most dramatic they’d seen in 40 years. These tiny birds, weighing 1 to 2 ounces, need to catch a tailwind if they’re to make it south and find food before colder days set in. There just aren’t as many insects around at the time of this writing as there were a week ago. 

So when they arrive in the city, birds can’t perceive glass the way humans do. As the American Bird Conservancy states, they perceive glass reflections of vegetation, landscapes, or sky to be real. That’s what happened last Thursday, when the number of collision deaths at Chicago’s McCormick Place convention center made national news. 

There are voluntary steps to prevent collisions—from tape on glass to “lights out” initiatives—that any business or homeowner can take. In this case, McCormick Place says it’s “working with experts,” to prevent future collisions. It will take continued public awareness efforts to convince building managers to prevent collisions.

A small silver lining is that elected officials including a Congressman, the Mayor, and an Alderman have issued statements about last week’s deadly event. That’s not something we’ve seen before, if I recall correctly. It may have taken such a terrible event to finally draw attention to what has felt like an intractable problem.