Migration: Following the Stars

BirdNote^®

Migration: Following the Stars

This is BirdNote!
[Music from Ottorino Respighi’s The Birds runs throughout.]
Imagine flying thousands of miles without map or compass. Imagine covering those miles in the dark of night. Tonight and throughout this month, songbirds are traveling north on their annual spring migration.
For years, scientists wondered why songbirds migrate at night. Studies show that some songbirds use stars to help orient them. In a controlled experiment, scientists created an artificial nighttime sky inside a large enclosure. However, the north/south directions were reversed so the pattern of northern stars actually faced south. The scientists then released northern-migrating songbirds into the enclosure and watched carefully as the birds took off. The migrating birds flew in the direction of the fake northern stars rather than toward true north.
Although this experiment explains a bit about bird migration, the essential phenomenon remains a mystery—for example, how birds winter thousands of miles away, yet return to the same tree to nest as they did the year before. Or how young birds head south weeks after their parents leave, to find their wintering grounds.
One thing we know: the songbirds migrating overhead tonight will be keeping an eye on the stars as they head north.
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Music: from Ottorino Respighi's The Birds
Producer: John Kessler
Executive Producer: Chris Peterson
© 2008 Tune In to Nature.org                April 2010

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