Birds Use Light, Not Magnetic Field, to Migrate

[The Straight Story]

Birds Use Light, Not Magnetic Field, to Migrate

A cell in the eye may be worth two in the beak, at least when it comes to a migratory bird’s magnetic compass. In European robins, a visual center in the brain and light-sensing cells in the eye — not magnetic sensing cells in the beak — allow the songbirds to sense which direction is north and migrate correctly, a new study finds. The study, appearing Oct. 29 in Nature, may improve conservation efforts for migratory birds.

sciencenews“This is really fascinating science,” says biophysicist Klaus Schultenof the University of Illinois at Urbana-Champaign, who was one of the first to suggest that migrating birds can sense magnetic fields.

Researchers have known that built-in biological compasses tell migrating birds which way to fly, but the details of how birds detect magnetic fields has been unclear.

“This is basically the sixth sense of biology, but no one knows how it works,” says study co-author Henrik Mouritsenof the University of Oldenburg in Germany. “The magnetic sense is by far the least-understood sense in the natural world.”

http://www.wired.com/wiredscience/2009/10/bird-migration-light/

[TexasObserver]

1. That makes sense, since we know that magnetic North and South switch.

I don't know the intervals involved, but North and South magnetic poles switch periodically in earth's history.