For years, it has been assumed that a staggering number of birds die in collisions with buildings in the United States — between 100 million and one billion every year. The total is often cited as fact, even though it was presented, in 1990, as only a rough estimate.
Now, in a study published in early January in The Condor: Ornithological Applications, the journal of the Cooper Ornithological Society, researchers say the totals are accurate. About 600 million and possibly up to one billion birds die each year from collisions with buildings, and especially windows.
Bird-building collisions are the second-highest cause of death in birds in the U.S. caused by humans. Only feral and free-ranging pet cats kill more birds than building collisions, says lead author Scott R. Loss.
His report is the first of its kind to use data from multiple studies to estimate the number of birds killed each year by collisions with U.S. buildings. We’ll have more about his important research in our upcoming April 2014 issue.
You can help researchers learn more about how many birds die from collisions by assisting with a collision-monitoring program — or by starting one. And you can help reduce the number of birds killed by collisions at your home by placing decals close together (within 5–10 cm of each other) on windows or locating bird feeders within one meter of windows so that birds have less momentum after taking off from a feeder if they do hit a window.
For larger buildings, such as low-rises and high-rises, research has shown that turning off lights at night reduces collision rates. “Many birds migrate at night, and bright lights disorient and attract them,” Loss says. “Birds either immediately collide with lighted buildings, or they become entrapped in the mazes of windows at street-level until they tire out or die from colliding with windows.” — Chuck Hagner, Editor
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