[Tweeters] Above-normal numbers of Lewis's and Acorn Woodpeckers

Wayne Weber contopus at telus.net
Fri Oct 1 09:21:41 PDT 2010


Tweeters,



With all due respect to Dennis Paulson, I beg to differ in my
interpretation of the reasons for above-average numbers of Acorn and Lewis's
Woodpeckers in western WA this year.



Dennis's explanation (poor acorn crop) seems quite reasonable for Acorn
Woodpecker. This is a species which barely gets into WA (mainly Klickitat
Co.); most of the WA and BC records this year are likely vagrants from OR or
farther south. This species is non-migratory and generally stays in the same
area throughout the year. It is also very rare as a vagrant anywhere outside
its normal range, so the several records in BC and WA this year are quite
extraordinary.



However, the situation with Lewis's Woodpecker is quite different. This is a
species which breeds north well into B.C.; there are probably several
thousand breeding pairs in BC. (You can check out the breeding range of
Lewis's in BC by going to the species maps on the BC Breeding Bird Atlas
website at http://www.birdatlas.bc.ca/bcdata/maps.jsp ). At Vancouver,
Lewis's are seen regularly every fall (averaging 2-3 records per year,
sometimes of singles and sometimes small flocks), and more rarely in spring.
The species is highly migratory, and winters mainly in California, with
smaller numbers in OR and the southwestern states. The number of Lewis's
records in western WA this fall is above average, but does not strike me as
exceptional. Lewis's Woodpeckers in BC and WA breed mainly in areas with no
oaks (with the exception of the Fort Simcoe area, where they breed in a
large oak stand). Birds migrating from BC or north-central WA through
western WA would have no way of telling whether acorn crops in Oregon are
above or below normal. Therefore, I seriously doubt that acorn crops have
anything to do with the number of Lewis's being seen in western WA.



It's often hard to determine the reasons for multiple extralimital
occurrences (e.g. Acorn Woodpeckers), or for conspicuous variation in the
numbers of normal migrants (which I think applies to Lewis's in western WA),
but I agree that it is worthwhile trying to relate these kinds of events to
environmental factors such as weather or food availability.



Wayne C. Weber

Delta, BC

contopus at telus.net











From: tweeters-bounces at mailman2.u.washington.edu
[mailto:tweeters-bounces at mailman2.u.washington.edu] On Behalf Of Dennis
Paulson
Sent: September-30-10 5:56 PM
To: TWEETERS tweeters; Wayne Weber
Subject: Re: [Tweeters] Lewis's Woodpeckers near Deming, Whatcom Co.



Wayne, et al



With the Acorn Woodpecker in Magnuson Park today, that makes an
unprecedented number of records of both Lewis's and Acorn in western
Washington in the past few weeks. I notice also that both species were just
mentioned from western Oregon in the Oregon rare bird report on tweeters.



My guess is that this is a consequence of a failure of the acorn crop
somewhere to the south of us, with birds dispersing well away from their
normal haunts in search of winter sustenance. It would be very interesting
to find out if anyone in the range of the Garry oak woodlands knows more
about this.



Dennis




Date: Wed, 29 Sep 2010 16:55:15 -0700
From: "Wayne Weber" <contopus at telus.net>
Subject: [Tweeters] Lewis's Woodpeckers near Deming, Whatcom Co.
To: "TWEETERS" <tweeters at u.washington.edu>

Tweeters,

In case anyone was wondering about my cryptic reference to Lewis's
Woodpeckers in Whatcom County, 2 of them were reported to be flycatching
near a barn along Truck Road (just off the Mount Baker Highway east of
Deming) by a person called Fanter Lane on September 24 (message to the
Whatcom Birds group). I looked for the birds the next day, as did
Bellingham birders Phil Wegener and Barry Ulman, but we could not find them.
However, there were several raptors in the area including a TURKEY VULTURE,
COOPER'S HAWK, RED-TAILED HAWK, and 2 BALD EAGLES.

If we add these to other recent reports, there have been sightings in the
last week of Lewis's Woodpeckers in Whatcom, Skagit, Snohomish, and King
Counties, at least. There were also 2 or 3 seen in the Vancouver, BC
area earlier in September.

Wayne C. Weber
Delta, BC
contopus at telus.net





-----

Dennis Paulson

1724 NE 98 St.

Seattle, WA 98115

206-528-1382

dennispaulson at comcast.net









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