|Image from NASA's The Gateway to Astronaut Photography of Earth|
Toronto is home to the Fatal Light Awareness Program (FLAP). The organizers of FLAP have been working hard to raise awareness that illuminated buildings are a danger to birds. Each year in Toronto, over a million birds are killed by colliding with buildings. They are attracted by light at night and either collide with buildings or become trapped in beams of light and fly until they are exhausted. Migratory birds are especially prone to the dangers posed by city lights.
Have a look at their website to learn more.