In message <9502171903.AA20283 at beaufort.sfu.ca> writes:
> Dear Tweeters and Obolers (sorry to those who will get this twice)
>
> I am interested in finding out a little about the _oedicus_ subspecies
> of the Swainson's Thrush which is supposed to extend up to n. Washington
> and Oregon along the **east** slope of the Cascades from California. I have
> not seen specimens of this guy, but I assume that it is a "Russet-backed"
> Swainson's, is this true? As well, how does it differ from typical
> _ustulatus_
> Swainson's from further north?
> Here in B.C., the Western Veery breeds in areas sympatrically with
> _almae_ Swainson's which is a really grey type of "Olive-backed" Swainson's
> Thrush so it is no problem to differentiate between the two. It appears
> that further south it gets a little trickier as a "Russet-backed" Swainson's
> will be found with the Veery. Such is life.
> Finally, have any of you regularly seen Olive-backed Swainson's as migrants
> at coastal sites? I think that this may be more common than is generally
> accepted, but I would like to have some data.
>
> Thanks
>
> Alvaro Jaramillo
> jaramill at sfu.ca
> Vanouver, B.C.
>
>
Al,
The California Swainson Thrush, _H. u. oedica_ Oberholser, breeds along the
east side of the Cascades from Goldendale to Lake Wenatchee.Jewett et al.
list four specimens from WA and states that they extend the northern limit
of this subspecies (to Lake Wenatchee). The Northern Swanison Thrush or
just Swainson Thrush _H. u. swainsoni_ breeds in Idaho and northeastern
Washington. I can tell these apart in the hand, with _swainsoni_ having
little or no rufous on its tail. I haven't banded in northern
Chelan or western Okanogan Cos. so I am not certain if intergrades exist.
_oedica_ has a fairly rufescent tail, with an olive/gray back. I believe
_ustulata_ breeds through out western WA west of the Cascade crest. I have
banded many of these birds, they have a browner back than _oedica_. Their tail
is slightly more rufous that their back (which is brown).
I have been banding in eastern WA for only about 5 years, so my experience
with these birds is limited; but I will be banding alot in the future and hope
to iron-out the details of passerine subspecies distribution in e. WA.
I have only one specimen of Swanison's Thrush in my little collection; I'm
sure Dennis Paulson could shed more light on the situation.




Dan Stephens (509) 662-7443
Dept. of Biology fax: (509) 664-2538
Wenatchee Valley College e-mail: dstephen at ctc.edu
1300 Fifth Street
Wenatchee, WA 98801