How migrating birds 'run a marathon,' burning muscles and organs in long flights

(University of Massachusetts at Amherst) Migrating birds complete long non-stop flights of many hours for songbirds and days for some shorebirds to reach breeding or wintering grounds. During such flights a bird's metabolic rate is very high, fueled by stored fat, but also by burning the protein in muscles and organs in a process that is not well understood, says eco-physiologist Alexander Gerson at UMass Amherst. He has a new grant to study the processes involved.