In the spring and fall migration seasons each year, billions of birds wind through the central U.S. as they soar the skies between Latin America and Canada. For many, the journey is deadly. Recent research from the Cornell Lab of Ornithology in New York estimates that a whopping 600 million birds in the U.S. die every year after crashing into tall buildings.
And for traveling birds, Chicago — where a skyline of glass and steel stretches across a heavily trafficked migration route — may be the most perilous of all U.S. cities. Many strike the windows of McCormick Place, the largest convention center in North America.
Yet these tragic collisions have borne surprising scientific fruit. Over the last 40 years, scientists and volunteers from Chicago's Field Museum have collected thousands of fallen birds outside the stocky glass building and its neighboring skyscrapers. Dave Willard, the museum’s collection manager emeritus, took it on himself to measure each of the dead animals and catalog the data by hand in a ledger.
