on 1/12/07 4:45 PM, Bud E-mail at bud at frg.org wrote:

Hi,
Peregrines do carry ducks regularly but I think that there are several
factors influencing this behavior.
For example, we have the world's largest peregrine residing in Washington,
the Peale's Falcon (incidentally, the type specimen was collected somewhere
in south Puget Sound by Titian Ramsey Peale while he was a member of the
Wilkes Expedition).
Female Peale's Falcons can weigh 1,350 grams (48 ounces) which is 3
pounds. That's a big peregrine. There are male Gyrfalcons that weigh in at 3
pounds or less.
Since they are so much bigger, Peale's are able to carry a larger prey
item than the smaller, lighter Tundra Peregrine. Although I have to say that
I once followed a tundra bird as it carried a Blue-winged Teal (very low to
the sand) for over two miles on Padre Island, Texas. But I was also pushing
her.
To complicate matters, male peregrines usually weigh about a third less
than a female. So they are less capable of carrying the large duck species.
They will take a few GW Teal, etc. but usually they seem to prefer smaller
birds, like sandpipers which they can carry off and eat with no problem.
Most of the successful hunts that I have observed, primarily on the Samish
Flats, have involved adult female peregrines and Bufflehead or GW Teal. A
female peregrine can pack these quite nicely. These seem to be a preferred
prey on Samish. The Wigeon kills are a different story. I have usually seen
the falcons eating these heavier


You mention body weight (size) of the preditor but not the comparative
weight of the prey. . .

A reasonable comparison. . .

Bill Kaufman
Woodinville, WA

birds directly on the ground. They might be able to carry them, as Kelly
mentions, but certainly not with a hungry Bald Eagle after them.
A falconer, Brett Gaussoin, reportedly observed an adult female peregrine
carry a recently caught GW Teal up to a good elevation over the
predator-dense Lummi Flats in winter and eat it entirely on the wing. This
behavior was interpreted to be a response to avoid kleptoparasitism by other
raptors on the ground.
I suspect that there are many other factors involved in carrying ducks.
For example the level of hunger, motivation and personality of a specific
bird, whether there is a strong wind, the appearance of competitors, the
presence of strong updrafts at cliff nest sites, stuff like that.
I think that the main point, for me anyway, is that it is always
noteworthy to see a successful peregrine hunt. In my experience, witnessing
these events is relatively rare.

Bud Anderson
Falcon Research Group
Box 248
Bow, WA 98232
(360) 757-1911
bud at frg.org

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