Frigatebird in flight. (Photo: Charles Davies)
Two Frigatebirds perched in greenery. (Photo: Ronald Woan)
Frigate birds are one of the only seabirds with feathers that are not water-proof, but as Michael Stein explains, their ability to stay airborne for weeks at a time makes up for that trait.
[BIRDNOTE THEME]
CURWOOD: Time for a flight of fancy now, way up over the warm southern oceans with one of the most iconic and breathtaking of all tropical sea birds. But as Michael Stein explains, this is a sea bird with an unusual aversion to the actual water.
BirdNote®
Frigatebirds: Seabirds That Can’t Get Wet
[Magnificent Frigatebird, http://macaulaylibrary.org/audio/136235, 0.13-18]
STEIN: Soaring above the warm oceans of the world, frigatebirds cut a distinctive profile: huge, slim, angular black birds with a 7-foot wingspan and long, scissor-like tails. They blithely chase down smaller birds like boobies to steal their fishy prey or drop to just above the surface and snatch fish from the water. Perched atop a rocky islet or dead mangrove tree, they look like seagoing vultures.
But one thing you’ll never see is a frigatebird floating on the ocean. Because their feathers -- unlike those of nearly all other seabirds -- are not waterproof.
Instead, the frigatebird is a master of staying aloft. Tracking devices placed on frigatebirds near Madagascar showed that they often stay in the air for a month and half at a time! They’ll soar above the ocean, riding a complex roller coaster of air.
Frigatebird in flight. (Photo: Charles Davies)
Intentionally flying into a cumulus cloud, which has a powerful updraft, they may rise as high as 2½ miles into the frigid atmosphere. From this high point, a frigatebird can glide more than 35 miles without flapping its wings.
Which is how this seabird that can’t get its feathers wet -- survives over the open ocean.
[Magnificent Frigatebird calls, http://macaulaylibrary.org/audio/136232, 0.05-.08]
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Written by Bob Sundstrom
Bird sounds provided by The Macaulay Library of Natural Sounds at the Cornell Lab of Ornithology, Ithaca, New York. [136235 and 136232] recorded by Martha J Fischer.
BirdNote’s theme music was composed and played by Nancy Rumbel and John Kessler.
Producer: John Kessler
Executive Producer: Sallie Bodie
© 2016 Tune In to Nature.org November 2016 Narrator: Michael Stein
CURWOOD: For pictures of these majestic frigate birds, coast on over to our website, LOE.org.
Links http://birdnote.org/show/frigatebirds-seabirds-cant-get-wet - Hear this segment on the BirdNote website https://whyevolutionistrue.wordpress.com/2016/07/06/how-frigatebirds-stay-aloft-for-weeks-and-weeks/ - More on Frigatebird flight