Why Frigatebirds Can’t Float

The seabirds can stay aloft over the open ocean for months, but they don't really have a choice.

This audio story is brought to you by BirdNote, a partner of The National Audubon Society. BirdNote episodes air daily on public radio stations nationwide.

Episode Transcript: ​

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.  

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.



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

Narrator: Michael Stein

© 2016 Tune In to Nature.org   November 2016