Birds may slam into windows, walls, floodlights, or even the ground. The problem is particularly acute when the weather is bad. On a rainy, foggy Labor Day weekend in 1981, more than 10,000 birds collided with the floodlit smokestacks at Ontario's Hydro Lennox Generating Station, near Kingston. Birds that are distracted by tower lights also may end up crashing into one another. They are apparently trying to orient their flight to the light, which they mistake for the moon or a star.
Nobody is certain of the total number killed across North America.
A tall building in the path of a migration can claim hundreds of lives. Passerines are not the only order of birds waylaid by lights. The Newell's shearwater, an endangered Hawaiian seabird, is particularly vulnerable. After their parents abandon their cliffside nests in October and November, fledglings make their first flights by relying on their innate attraction to light to guide them. Normally, because of the light's reflection on water, they fly out to sea, toward the horizon.