Why do birds collide with buildings?
A. Most birds migrate at night and can be drawn off course by tall, lighted structures in their flight path. Scientists are not sure why this happens but it may be related to the fact that among many navigational clues, birds use the stars to stay on course. Lighted high-rise buildings may simply confuse them. Once among the lights, birds seem reluctant to fly out and become “trapped” in urban areas. Sometimes they strike buildings/windows outright during the night. However, many of the collisions take place during daylight hours when birds, which cannot perceive glass as an obstacle, fly into clear glass or windows that reflect vegetation.
