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

Dennis Paulson dennispaulson at comcast.net
Sat Oct 2 08:01:57 PDT 2010


Hello, all.

With all due respect to Wayne, I'm not persuaded by his argument. I do know that Lewis's Woodpeckers are migratory in BC and most of their WA range, as also are some OR populations, but there are also many resident populations, north to Fort Simcoe, as Wayne mentioned.

We have now heard about much reduced acorn crops in Klickitat County from Joe Higbee and east of Mt. Hood from Dave Catterson.

These are exactly the places where Lewis's Woodpeckers are *resident* in large tracts of oaks not that far from the Puget Sound lowlands. I will speculate again that these birds have dispersed away from those sites because of the scarcity of acorns. Because they are resident, they are just as likely to disperse north and west as east and south - just as the Acorn Woodpeckers seem to be doing. On the other hand, I can't come up with a reason why migratory Lewis's should all of a sudden be much more common than usual in western Washington.

And the numbers *are* exceptional, as I read the tweeters digest day after day. I can envision a southbound migrant passing a northbound disperser in the sky, both thinking ?????

Dennis


On Oct 1, 2010, at 9:21 AM, Wayne Weber wrote:


> 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

>

>

>

>


-----
Dennis Paulson
1724 NE 98 St.
Seattle, WA 98115
206-528-1382
dennispaulson at comcast.net



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