Tweets,

Three ornithological observations from the center of the state, ranked from
beginner to advanced:

Today (12 May) in my yard in Wenatchee: Western Tanager-2 (first of the year),
Vaux's Swift-2 (feeding overhead) , Cedar Waxwing-2 (present all year),
Evening Grosbeak-40 to 50 (first large flocks this spring, previous high 4 at a
time), Yellow-rumped Warbler-0 (up to 30 in the yard at a time in late April).

At Atkin's Lake in Douglas Co. (11 May) a Western and Clark's Grebe starting to
court. Several pair of Eared Grebe nested at Atkin's last year. 30 Eared seen
on the Lake on Saturday.

And (the best for last) a Western Flycatcher 'Pacific-slope' and a Western
Flycatcher 'Cordilleran' caught in the same net at the same time on Saturday
at the famous Douglas Creek Banding Station. The brit ringer there to observe
was thanking his lucky stars there were no Empids in England. You may be asking
how I knew the difference in hand. It takes a while, Pyle et.al.,and some
experience. I am familiar with the Cordilleran (then Western) from years of
banding and birding Idaho. It is the (Cordilleran) that breeds in the
Cottonwood riparian strips in Columbia, Garfield and Asotin Counties (in my
humble opinion) where I've seen and heard them the last 3 years. What happens
between Columbia County and the Cascades is a mystery. I've been banding at
Douglas Creek for 5 years and have caught, seen, and heard Western Flycatchers.
In my opinion (and without much hard evidence- I like limbs) I am in an
introgression zone between Cordilleran and Pacific-slope Flycatchers. I believe
the Cordilleran in SE Washington are pure Cordilleran (perhaps an ecotype as
they tend to be found in dry Douglas-fir in Idaho) if there is such a thing; and
the Pacific-slope along the east-slope of the Cascades (such as at the
Leavenworth Fish Hatchery) are also 'pure'. Then again it is possible that the
entire Cottonwood population of Western Flycatcher between Idaho and the
Cascades is best explained by the bounded superiority model of Moore (Moore,
W.S. 1977. An analysis of narrow hybrid zones in vertebrates. Q.Rev. Biol 52:
263-278). I've lived in Western Washington (Pacific-slope) and Idaho
(Cordilleran), and believe that the cottonwood woodlands along the eastern edge
of the Cascades is a hybrid zone for this species complex. I also believe the
superspecies concept fits this group well (see the preface to 6th edition of the
AOU Checklist). Questions? (sorry no answers, only more questions). Anyway some
food for thought for some tweets. Enough rambling- back to grading zo exams.
Dan





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