Why do birds face the same direction on power lines?

I saw hundreds of birds land on a telephone line and it seemed all were facing in the same direction. Is anyone aware of a reason why? Thanks!

Image by mikelietz via Flickr

Scientists believe the main reason that birds face the same way on a wire is due to the direction of the wind. Birds have an easier time taking off and landing facing the wind.

Birds sit on power lines, trees, roofs or any perch, facing into the wind. Any other direction would ruffle their feathers. It's also easier to communicate.