One bird of prey may steal another's meal, a behavior that biologists call piracy, or kleptoparasitism. The prey may change hands several times, perhaps from Northern Harrier to Peregrine Falcon to Bald Eagle. The Peregrine - like the young one seen here - may steal a meal, or have its meal stolen, or both! Visit your local Audubon chapter, to see where you might watch raptors this winter.
Piracy Among Raptors
Written by Bob Sundstrom
This is BirdNote! [Whistled calls of a Northern Harrier]
It’s early morning, and the winter sunrise bathes the horizon in pink. A Northern Harrier – a lanky, low-flying hawk – systematically covers a broad expanse of open ground. The harrier flies slowly on canted wings, hunting just a few feet above the grass-covered earth. [Call of a Northern Harrier] With a sudden, mid-air twist, it slams its talons toward the ground, catching an unwary rodent.
Just as the Northern Harrier lowers its head to partake of its quarry, a swift Peregrine Falcon streaks in on long, angled wings, knocking the harrier off its still-warm prey.
By snatching the harrier’s first morning meal, the falcon saves itself the time and effort of foraging. Biologists call this behavior piracy, or kleptoparasitism.
It’s a scene repeated in many areas across North America where birds of prey congregate in winter. In truth, piracy is almost routine – as our Peregrine Falcon is about to find out. Because just as the falcon took from the harrier and is now about to dine, a massive Bald Eagle – which had watched the entire drama unfold – flies in from a nearby perch to relieve the falcon of its already-once-purloined prey. [Call of Bald Eagle]
The eagle had better eat quickly. Other eagles are watching. [Calls of two Bald Eagles]
Call of raptors provided by The Macaulay Library of Natural Sounds at the Cornell Lab of Ornithology, Ithaca, New York. Northern Harrier recorded by W.W.H. Gunn; Bald Eagle individual and pair, recorded by J. Storm.
Padilla Bay ambient recorded by C. Peterson
Producer: John Kessler
Executive Producer: Chris Peterson
© 2015 Tune In to Nature.org January 2017 Narrator: Michael Stein