The Problem
"During their migratory season, millions of birds representing hundreds of species fly through our city on their way to their summer or winter homes. Lights from tall buildings can disrupt these migratory paths, causing birds to circle buildings repeatedly. As a result, many of them die from exhaustion or after colliding with a building.”  Lights Out Chicago

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Studies show an estimated 600 million birds a year die after hitting windows in the US and Canada. The problem is that windows reflect the sky and trees, and birds can't tell the difference. Lights left shining in glass buildings at night also draw birds, especially during migration periods -- like the one about to happen this fall. This happens with high-rise buildings, as well as, homes and offices." Source