Migratory songbirds eat billions of insects, and they disperse billions of seeds .
They migrate at night to escape predators. During the day, they can rest and eat, and the daylight helps them see predators better . Many of the insect eating birds that migrate do so at night. They use constellations for directions, and lights on tall, man-made structures attract these birds causing them to collide with it . Scientists have estimated that domestic cats kill hundreds of millions of birds each year .