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Frigatebird Migration

July 5, 2016

Solar transmitters on ocean-going frigatebirds reveal how they keep aloft for months at a time.

Transcript

Charles Sharp CC BY 2.0, via flickr B

A male great frigatebird in flight. (Charles Sharp CC BY 2.0, via flickr)

BOB HIRSHON (host):

A seabird’s grand journey. I’m Bob Hirshon and this is Science Update.

Great frigatebirds soar above the Indian Ocean for several months at a time without ever landing, even on water.

HENRI WEIMERSKIRCH (CNRS):

Their plumage is not waterproof, so they have to stay contunuously in flight.

HIRSHON:

That’s French National Center for Scientific Research ecologist Henri Weimerskirch, who says the frigatebirds feed by snatching flying fish out of the air. To discover how they accomplish their migratory feats of endurance, his team tracked the birds with solar-powered satellite transmitters. They report in Science magazine that the birds catch a ride on thermal updrafts, soaring more than 250 miles per day while expending almost no energy on flapping. What’s more, the birds even sleep on the wing, but only for several minutes at a time as the tradewinds lift them up to 13,000 feet in the air.

WEIMERSKIRCH:

In two months you can cross the entire ocean.

HIRSHON:

I’m Bob Hirshon, for AAAS, the science society.

Story by Susanne Bard