Speaking of phylogenetic species, I was excited to be able to study
Swainson's Thrushes in Okanogan County last weekend. Not only are they one
of the "olive-backed" subspecies, much less reddish than our
"russet-backed" birds west of the Cascades, but their call is different
from the latter birds. Russet-backs give a rather soft, light 'whit' as
their alarm call, while the call of the olive-backs was a much more
vigorous 'wip' or 'pip' (hard to describe, but really different). I
thought that birds in the south Cascades gave the soft 'whit' call, but now
I'll have to reconfirm that.

Also, these thrushes breed way up in the mountain conifer forests over
there, in the same habitat I usually associate with Hermit Thrushes rather
than the lower, wetter environments in which they breed west of the
Cascades and, to some, degree, on the east side farther south. At several
sites at around 4,000' or higher, there were Swainson's but not Hermit.
It's interesting that in the East the Swainson's is a high-mountain thrush.
Do we have another incipient species split here, a la Gray-cheeked and
Bicknell's?

Any comments, you widespread tweeters? Are you there, Alvaro?

Dennis Paulson, Director phone: (206) 756-3798
Slater Museum of Natural History fax: (206) 756-3352
University of Puget Sound e-mail: dpaulson at ups.edu
Tacoma, WA 98416