Frigatebirds' Kleptoparasitism

In the warmer regions of the world’s oceans, large seabirds called boobies plunge headfirst into the water, snatching up fish. But as a booby flies up from the waves with a fish now in its gullet, there may be another big seabird — a frigatebird — with its eye on the booby’s fresh catch. Now begins one of nature’s great chase scenes. Fortunately for boobies, frigatebirds don’t steal all their meals. Most of the time, they hunt their own seafood — perhaps a squid snapped from the ocean surface or a flying fish as it skims across the waves.

(In this photo, the frigatebird is attacking a tropicbird, another frequent victim.)

This story was produced with support from the Bobolink Foundation.

BirdNote^®

Frigatebirds’ Kleptoparasitism

Written by Bob Sundstrom

This is BirdNote.

[Featured bird sound/audio]

Some birds are masters at catching fish. In the warmer regions of the world’s oceans, large seabirds called boobies plunge headfirst into the water, snatching fish in their dagger-shaped bills.

But as a booby flies up from the waves with a fish now in its gullet, there may be another big seabird, a frigatebird, waiting overhead. With its eye on the booby — and on the booby’s fresh catch.

[Red-footed Booby aggressive call, http://macaulaylibrary.org/audio/6036, .32-.33]

Now begins one of nature’s great chase scenes. The booby flaps full throttle away from the frigatebird. But there’s no escaping. With a light body suspended on long, narrow wings and a long, scissor-like tail to match, the frigatebird is faster and more agile. It lopes up behind the frantic booby and, with its long, slender, hooked bill, clamps onto the booby’s tail or wing-tip. Thus snagged in mid-air, the booby flails. A crash is imminent, unless it surrenders what the frigatebird wants. So it disgorges the fish it’s just captured. The frigatebird releases the booby and swiftly snatches the free-falling fish.

[Magnificent Frigatebird, http://macaulaylibrary.org/audio/136232, 0.04-.06]

Fortunately for boobies, frigatebirds don’t steal all their meals. Most of the time, they hunt their own seafood — perhaps a squid snapped from the ocean surface or a flying fish as it skims across the waves.

But now and again, when a chance comes up, they’ll take it.

For BirdNote, I’m Mary McCann.

[Magnificent Frigatebird, http://macaulaylibrary.org/audio/136232, 0.04-.06]

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Bird sounds provided by The Macaulay Library of Natural Sounds at the Cornell Lab of Ornithology, Ithaca, New York.
6036 recorded by Robert J. Shallenberger 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
© 2017 Tune In to Nature.org March 2017/2019 Narrator: Mary McCann

ID# frigatebird-02-2017-03-28 frigatebird-02

Video of frigatebird kleptoparasitism: https://www.youtube.com/watch?v=ifes66o4t7s
Another good source is http://animaldiversity.org/accounts/Fregatidae/