I thought I might pop into the discussion, although I might not be adding
anything significant.

I like the image Dennis gave at the end of his post - the dispersing Lewis's
Woodpeckers passing their migrating conspecifics in confusion.

Although it may be apparent to everyone, I think in this discussion it is
important to note that acorns are an important source of fall and winter
food for Lewis's Woodpeckers (which has been inferred but not ever stated,
unless I've missed it and then I apologize for the repetition). After all,
they can't catch enough insects all year long in some of their range. They
haven't built up their habit quite so exquisitely as their congeners, but
they do store acorns too. Knowing this, I think it makes sense that many of
these birds could be residents dispersing to look for food.

Although nothing I've read ever gave a good reason for their wanderings,
beyond looking for food (a good one of course), Lewis's Woodpeckers are
known to do it. Nomadic birds (sometimes in small groups according to the
literature) could possibly be individuals that left an area with a poor
acorn crop. Knowing the variability of most plant crops, it isn't difficult
to expect birds to be flexible and opportunistic in their residency (think
of all the unripe tomatoes we've got on our vines still).

Irregardless of the specifics of why they are here, I think those of us West
of the Cascades should count ourselves lucky that we get to see either of
these species so close to home. Two weeks ago I had two Lewis's Woodpeckers
in my parents' backyard in N. Seattle, which I admit I did not report here
(only on Ebird). I was pretty stunned to have not only one but two
flycatching in their backyard.

Cheers!
--

-Brendan McGarry
Seattle, WA
groovypenguin at gmail.com
http://www.brendanmcgarry.com
visit my blog at http://wingtrip.org
check out my photos at http://www.flickr.com/photos/brendanmcgarry
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