[birding] possible Swainson's Hawk Linn County

Joel Geier joel.geier at peak.org
Sun Dec 21 08:39:16 PST 2008


Hello folks,

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.

Happy reading,
Joel

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.
>
> http://www.pbase.com/marvbreece/image/62305272
>
> http://flickr.com/photos/hearman/2381254521/
>
> That is my take and advice anyway :-)

--
Joel Geier
Camp Adair area north of Corvallis




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