Lights out, Chicago! Millions of birds expected to migrate over city in next two days
(Chicago Tribune Religion News)

Over the next two nights, millions of birds are expected to migrate across Chicagoland in one of the biggest migration movements of the season so far, according to the Chicago Bird Collision Monitors. But with migration comes lethal dangers, including high-speed crashes into building windows. Conservationists are urging building owners and residents to turn their lights off to help reduce the number of collisions.