[birding] possible Swainson's Hawk Linn County
joel.geier at peak.org
Sun Dec 21 08:39:16 PST 2008
I ran the Linn Co. mystery hawk's photo by Trent Seager, who worked for a
number of years as a Swainson's (& Ferruginous) Hawk researcher.
Below are his comments on this bird, forwarded with permission.
On Fri, 2008-12-19 at 19:46 -0800, Trent Seager wrote:
> Hi Joel,
> Thanks for sending this along. I was curious right away to look at the pics
> - and I must say from a back only shot - this is like the raptor trick
> question of the winter!
> I used to say that adult SWHA are solid slate on the back, and have little
> to no streaking. But I have been proven wrong, by my own observations. So
> I now hold that -most- adult SWHA have little to no streaking on their back.
> And that, along with Occam's Razor, would lead me to think this a dark RLHA.
> Those 2 not being enough, I find the beak gives this buteo away. RLHA have
a very small beak. Whereas SWHA's beaks are similar in ratio size to their
> heads as a RTHA.
> The tiny beak size, the quick, sharp, curve down of the beak (no ground
> squirrel consumption over eons here) - and the coloration of the feathers on
> the back - and around the beak - all lead me to say RLHA.
> I believe that the SWHA has more full head of eye-beak-head ratio. The
> RLHA's in my mind have a larger forehead looks and even top-head look
> because the beak and eye are much smaller in proportion. Here are a few
> links that show a SWHA not quite at the same angle, but the beak is
> apparent, as is the eye and head ratio to my eye.
> That is my take and advice anyway :-)
Camp Adair area north of Corvallis
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