The stars provide an excellent navigating tool. Night-flying birds usually can't see the ground. Sometimes they end up over a huge lake or even the ocean, and by the time it's light are lost and have a long way to fly to reach land again. Since they can't see the ground, they have no idea what kind of habitat they are flying over. When day comes and they land, they may be in totally inappropriate habitat.
Songbirds have poor night vision.
They can see the stars fine, but in the dark can crash into mountains and other obstructions, including darkened buildings and dark towers. Their navigation system depends on seeing stars, and they get confused by and attracted to some kinds of artificial lights, crashing into lighted buildings and lighted towers. This kills millions of birds every year. In our May 3 update, we'll be asking for your feedback on the Journey North program. Watch for our Year-End Evaluation Form and please plan to take the time to send your suggestions and comments.