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Migration Along Orthodromic Sun Compass Routes by Arctic Birds

Authors :
Alerstam, Thomas
Gudmundsson, Gudmundur A.
Green, Martin
Hedenstrom, Anders
Source :
Science. January 12, 2001, Vol. 291 Issue 5502, 300
Publication Year :
2001

Abstract

Flight directions of birds migrating at high geographic and magnetic latitudes can be used to test bird orientation by celestial or geomagnetic compass systems under polar conditions. Migration patterns of arctic shorebirds, revealed by tracking radar studies during an icebreaker expedition along the Northwest Passage in 1999, support predicted sun compass trajectories but cannot be reconciled with orientation along either geographic or magnetic [oxodromes (rhumb lines). Sun compass routes are similar to orthodromes (great circle routes) at high latitudes, showing changing geographic courses as the birds traverse longitudes and their internal clock gets out of phase with local time. These routes bring the shorebirds from high arctic Canada to the east coast of North America, from which they make transoceanic flights to South America. The observations are also consistent with a migration link between Siberia and the Beaufort Sea region by way of sun compass routes across the Arctic Ocean.<br />How birds use different compass systems based on the sun, stars, and geomagnetic field to orient along their migration routes is not fully understood (1-4). The region at the Northwest [...]

Details

Language :
English
ISSN :
00368075
Volume :
291
Issue :
5502
Database :
Gale General OneFile
Journal :
Science
Publication Type :
Academic Journal
Accession number :
edsgcl.69961416