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Sizing Up Birds of Prey
© Paul Bannick
In most birds - if the sexes vary at all in size - the male is larger. But with many hawks and falcons, the pattern is reversed. And female birds of prey are most notably bigger than males among hawk species that hunt agile prey, such as other birds. Perhaps the female Cooper's Hawk's larger size ensures that she may dominate the male through courtship and nesting. And together they can tap a wider range of resources. Learn more about the Cooper's Hawk at Cornell's All About Birds.
BirdNote®
Sizing Up Birds of Prey
Written by Bob Sundstrom
This is BirdNote.
[calls of Cooper’s Hawks]
A mated pair of Cooper’s Hawks – swift, bird-catching predators – perch side by side, slender, dashing, gray and rufous hawks. The male is 15 inches long. The female, however, stands a head taller and outweighs him by half.
[repeat calls of Cooper’s Hawks]
This seems odd. In most birds – if the sexes vary at all in size – the male is larger. But with many hawks and falcons, the pattern is reversed. And female birds of prey are most notably bigger than males among hawk species that hunt very agile prey, such as other birds.
Why is this so? Perhaps the female Cooper’s Hawk’s larger size ensures that she may safely dominate the male through courtship and nesting – with a mate who is, after all, a highly aggressive bird-hunter. Perhaps also, the smaller male will tend to hunt smaller prey, while the female will take somewhat larger prey, so together they will tap a wider range of resources.
Despite his smaller size, the dapper male is a good provider. Early in nesting, while the female concentrates on incubating and brooding the hatchlings, the male does most of the hunting.
[repeat calls of Cooper’s Hawks]
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Call of the Cooper’s Hawk provided by The Macaulay Library of Natural Sounds at the Cornell Lab of Ornithology, Ithaca, New York. Recorded by G.A. Keller
Ambient recording by Kessler Productions
Producer: John Kessler
Executive Producer: Chris Peterson
© Seattle Audubon 02/07/06 © 2008 Tune In to Nature.org
ID#020706COHAKPLU COHA-01
Sights & Sounds
