Recipe for energy saving unravelled in migratory birds

The pointed wingtips of migrating bat, bird, and insect species alike were thought to have evolved to cut down energy expenditure during flight. Some researchers also predicted that carrying less weight for a given wing area and flying in certain atmospheric conditions should decrease the flight costs. Bowlin and Wikelski were finally able to put these ideas to the test in free-flying migrants.

“Until now, research on the energetics of small birds in flight was largely confined to individuals flying in artificial wind tunnels,” says lead author Melissa Bowlin, a post-doctoral fellow at the University of Montana. “Now, we can study small, free-flying birds making actual migratory flights in the wild.”

To track the thrushes during their spring migratory flights over the central USA, the researchers applied some modern technology. A temporary radio-transmitter, weighing less than one gram, fastened to the bird’s back sent the heart beat rate to an antenna on the ground. In order to receive these signals, Bowlin and Wikelski had to follow the sometimes rapidly moving birds with a radio-tracking vehicle. “We lost a few birds because we had to obey the speed limits on the roads but they didn’t,” says Bowlin.

Contact:
Prof. Dr. Martin Wikelski
Max Planck Institute for Ornithology (Ornithological Station Radolfzell), Germany
& Princeton University, USA
Tel. +1 609-933-6975
E-mail:

Dr. Melissa Bowlin
University of Montana, USA
E-mail:
Tel +1 607-227-6861
Note: Will be in the field until June 11; will return calls and e-mails ASAP.

Some pictures of Swainson’s thrushes are available.

Citation: Bowlin MS, Wikelski M (2008) Pointed Wings, Low Wingloading and Calm Air Reduce Migratory Flight Costs in Songbirds. PLoS ONE 3(5): e2154. doi:10.1371/journal.pone.0002154

PLEASE ADD THE LINK TO THE PUBLISHED ARTICLE IN ONLINE VERSIONS OF YOUR REPORT (URL live from May 14): http://www.plosone.org/doi/pone.0002154

PRESS-ONLY PREVIEW: http://www.plos.org/press/pone-03-05-bowlin.pdf

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