Hi Tweets,

I think Bob makes a good point here. The weights for different species
that are listed in the texts are a good reference, but they don't
necessarily represent the entire range of possible weights for a
species. It's reasonably safe to assume that the birds that become prey
are not going to be the healthiest, fittest, most powerful individuals.
They may already have issues that have led to significant decreases in
their body weight. We routinely receive ill or injured birds at our
rehabilitation center that are less than half of even the low end of
recorded weights for their species. They still appear to be the same
size as a healthy bird, but if you look beneath the feathers you find
nothing but skin and bones. An earlier post mentioned a Merlin carrying
a Rock Pigeon. Yes, it is hard to believe that a 190 g Merlin could
carry a 270 g healthy pigeon, but what about a190 g Merlin carrying a
100g, extremely emaciated pigeon? That definitely seems possible to me.

------------------------------------------------------------------------
------------
Kevin Mack
Naturalist, PAWS Wildlife Rehabilitation Center
425-787-2500 ext. 854
P.O. Box 1037 Lynnwood, WA 98046




________________________________

From: Bob Flores [mailto:rflores at nctv.com]
Sent: Saturday, January 13, 2007 9:38 AM
To: William Kaufman; Bud E-mail; Tweeters
Subject: Re: [Tweeters] Peregrines carrying ducks


I once came upon a peregrine carrying a male mallard because of my
action the peregrine has dropped the bird and I went over to see what it
was. The mallard still not eaten was rather light in weight. This is
not unusual in the winter months but is rarely indicated in text when
one reads of a birds "normal" weight. This occurred in Nevada about 8
years ago at the great Stillwater Marshes.

Bob Flores
Othello, WA

----- Original Message -----
From: William Kaufman <mailto:beaux at u.washington.edu>
To: Bud E-mail <mailto:bud at frg.org> ; Tweeters
<mailto:tweeters at u.washington.edu>
Sent: Friday, January 12, 2007 4:07 PM
Subject: Re: [Tweeters] Peregrines carrying ducks

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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