Fuel reserves affect migratory orientation of thrushes and
sparrows both before and after crossing an ecological barrier
near their breeding grounds Publikation/Tidskrift/Serie: Journal
of Avian Biology Förlag: Blackwell Publishing Ltd Fat reserves
influence the orientation of migrating songbirds at ecological
barriers, such as expansive water crossings. Upon encountering a
body of water, fat migrants usually cross the barrier exhibiting
'forward' migration in a seasonally appropriate direction. In
contrast, lean birds often exhibit temporary 'reverse'
orientation away from the water, possibly to lead them to
suitable habitats for refueling. Most examples of reverse
orientation are restricted to autumn migration and, in North
America, are largely limited to transcontinental migrants prior
to crossing the Gulf of Mexico. Little is known about the
orientation of lean birds after crossing an ecological barrier
or on the way to their breeding grounds. We examined the effect
of fat stores on migratory orientation