Navigator: How we know that migrating birds use the sun, stars, the magnetic field, and other cues to find their way

摘要

Imagine setting out on an ocean voyage without a compass. You might be able to steer a course for a while using the sun or stars. But as soon as clouds rolled in, you'd be lost. A magnetic compass, however, would enable you to find your way even undertotal cloud cover. Just as mariners rely on compasses, so too do migrating songbirds. Scientists have known for decades that migrants use the earth's magnetic field and the sun and stars to orient during migration. Topography is also useful, most likely as birds near their destinations.