Tweets,

Yesterday I battled the frigid winds at Kent in search of the Ross's Goose,
which wasn't there (at Boeing) first off but showed up about 2 PM near the
northwest corner of West Valley Highway and 212th St. It was approachable
near enough to see the gray-green cowling on the diminuitive pink bill. It
even yawned to show it had no black grin stripe. It was with a flock of
slightly larger Canadas which are too big and too variable to be Cackling
Canadas. (I just saw thousands of Cacklers in the Vancouver, Washington area
and the contrast with these birds is obvious.). I suspect they are what is
sometimes distinguished as "Taverner's Canada Goose (Branta canadensis
taverneri)," which is said to be intermediate between Lesser Canada (B. c.
parvipes; the common wintering Canada form in eastern Washington;
medium-sized with pale breast), Dusky Canada (B. c. occidentalis; which
winters commonly on Willapa Bay; medium-sized, dark breasted); and, perhaps,
also intergrading with Cackling Canadas (B. c. minima; very small; dark
breasted; higher pitched "cackling" calls), since Taverner's seems smaller
than Dusky. Taverner's breeds in southcentral Alaska between the ranges of
the Lesser, Dusky, and Cackling Canadas, and thus is likely a site of gene
exchange amongs those forms. In any case, the birds in the flock with the
Ross's Goose at Kent were medium-sized but varied in breast color from pale
to quite dusky. In addition, several showed narrow white collars between the
black "stocking" and the breast. These superficially resemble the threatened
Aleutian Canada Goose (B. c. leucopareia; wintering in northwestern
California, breeding in the Aleutians), but were too big. The Aleutian
Canada is supposed to be nearly as small as the Cackler (which would have
been as small as the Ross's, rather than noticeable larger, as in this case.
Last, but not least, there were some of our now-resident Great Basin Canada
Geese (B. c. moffitti; resident in the Columbia Plateau and the Great Basin)
in the Boeing field. Big, white breasted Canadas with the throaty honk that
gives them the moniker "honker." It is interesting to track the rather
dramatic recent changes in distributions of these forms. Of course, there's
the explosions of moffitti-type Canadas in Western Washington (and also
about Anchorage, Alaska?? How did they get there? Or is that another form of
Canada?); these were intentionally introduced in the Seattle area in the
1960s from birds rescued when their nesting areas on islands in the Columbia
River above the John Day dam were flooded (or so I've heard). Other changes
are not so obviously due to human intervention. It seems the current
abundance of Cackling Canadas wintering in the lower Columbia River valley
and the large numbers of Taverner's Canadas wintering in the Puget Sound
region is a very recent phenomenon (the past ten years). Alelutian Canadas
also seem to have made a dramatic comeback in California (and no doubt
occasionally stop off in western Washington in migration). Evolution in action.

Gene Hunn.