A proposal to blacken unnecessary lights in commercial buildings, a measure sponsored by the American Bird Conservancy, is being considered by San Francisco. Baltimore, too, has made a "lights out" policy part of its sustainability plan.
Why? Lighted skyscrapers send migratory birds off-course and often result in death-by-collision. As many as 975 million birds meet this fate each year, according to one estimate.
As the National Audubon Society put it, in one of its bird conservation tips for The Daily Green:
"Songbirds like bobolinks and hermit thrushes use constellations to guide them on their annual migrations, but bright lights in urban areas short-circuit their ability to steer. Every year millions crash into buildings and die. Close your curtains and blinds at night, turn out lights, and get your building manager to turn out lights that arent being used."
Of course, birds aren't the only reason to shut off unnecessary lights. An unnecessary light equals wasted energy, and the sum total of unnecessary light equals an obscured night sky (a.k.a. "light pollution), one in which the stars are difficult or impossible to see. The benefits of shutting out unnecessary lights are highlighted each year during Earth Hour.
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