>WASHINGTON (Reuters) - A sunset may do more than refresh the soul --
>it could recalibrate the internal compasses of migrating songbirds,
>U.S. and German researchers reported on Thursday.
>
>
>
>The researchers, who attached radio transmitters to thrushes and
>then followed them by car at night, said their findings help explain
>how birds fly across the equator at night without getting lost.
>
>The experiment, published in the journal Science, is one of the
>first to use free-flying birds instead of captive birds in a
>laboratory.
>
>Martin Wikelski of Princeton University in New Jersey and colleagues
>in the United States and Germany first caught several dozen thrushes
>and attached tiny radio transmitters to them.
>
>Knowing that birds use magnetic fields to orient themselves, they
>put some birds in an artificial magnetic field to confuse them, and
>then let them all go.
>
>The birds that had not been tricked flew north, as they usually do,
>but the birds exposed to the artificial field flew west, the
>researchers said.
>
>The next evening, all the birds were free to see the sun.
>Subsequently, all flew north again.
>
>"We suggest that birds orient with a magnetic compass calibrated
>daily from twilight cues," the researchers wrote.
>

--
Dennis Paulson, Director phone 253-879-3798
Slater Museum of Natural History fax 253-879-3352
University of Puget Sound e-mail dpaulson at ups.edu
1500 N. Warner, #1088
Tacoma, WA 98416-1088
http://www.ups.edu/biology/museum/museum.html
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