Tweeters and Vancouver Birders,

In my posting yesterday about the abundance of Eurasian Wigeon vs.
(Eurasian) Green-winged Teal, I forgot to mention a very good
scientific paper about the increase of Eurasian Wigeon in North
America which was published in 1984. For those of you that have access
to academic libraries, the reference is:

Edgell, M.C.R. 1984. Trans-hemispheric movements of Holarctic
Anatidae: the Eurasian Wigeon (Anas penelope L. ) in North America.
Journal of Biogeography 11:27-39.

Mike Edgell is a geography professor at the University of Victoria
with an interest in birds. His paper documented a 20-fold increase in
Eurasian Wigeon sightings between 1965 and 1981-- much more so on the
Pacific coast than on the Atlantic coast of N.A. He concluded that
much of the increase in sightings was due to a real increase in
wintering numbers, not just an increase in observers. Since Mike's
paper was published, the increase of wintering Eurasian Wigeon has
continued unabated, until now I find it unusual to see a flock of more
than 200 American Wigeon in winter without at least one Eurasian.

Wayne Weber
Kamloops and Delta, B.C.
wayne_weber at bc.sympatico.ca


-----Original Message-----
From: WAYNE WEBER <WAYNE_WEBER at bc.sympatico.ca>
To: TWEETERS <tweeters at u.washington.edu>
Cc: VANBIRDS <bcvanbirds at egroups.com>
Date: Friday, January 21, 2000 1:25 PM
Subject: EURASIAN WIGEON VS. EURASIAN GREEN-WINGED TEAL


>Tweeters and Vancouver Birders,
>
> In a message about 3 days ago, Lydia Gaebe asked which is more
>frequent in Tweeterdom-- Eurasian Wigeon, or (Eurasian) Green-winged
>Teal? This is a slightly belated response. As some of you are
>starting to realize, I like to give a statistical response to such
>questions whenever possible.
>
> In a nutshell-- Eurasian Wigeon is much more numerous than
>Eurasian Green-winged Teal, by at least 10 to 1. It has also
increased
>steadily in frequency as a wintering bird in the Pacific NW over the
>past 30 years, whereas I can detect no change in the status of
>Eurasian Green-wings.
>
> On the Ladner CBC, Eurasian Wigeon has been seen in 29 of the
last
>38 years, but has never been missed in the last 20. The average count
>of this species is 16 birds over the 38-year period, but in the last
>decade, it has averaged 45 birds. The high count is 74. Keep in mind
>that only the males are normally tallied, because the females are
>tough to identify, except for the rare rufous phase (which I have
seen
>3 or 4 times). So the actual numbers of Eurasian Wigeon are at least
>twice the numbers that have been reported. The status of this bird on
>the Vancouver bird checklist has increased from rare, to uncommon, to
>fairly common. I would say that currently, about 1% to 2% of wigeon
>wintering around Vancouver are Eurasians.
> On the other hand, Eurasian Green-wings have been seen only 4
>times in 38 years on the Ladner CBC. Eurasian X American intergrades
>have also been seen twice.
>
> On the Vancouver CBC, which has smaller counts of dabbling ducks
>than Ladner, Eurasian Wigeon numbers have averaged 7 over the last 31
>years, increasing to 15 in the last decade. However, the Eurasian
>Green-wing has been seen more often than at Ladner-- 6 times in 31
>years, plus 3 more times in count week. These are almost always
single
>birds.
>
> Eurasian Green-wings are probably not as rare, relative to
>Eurasian Wigeon, as these numbers suggest. They don't "stick out" as
>much as Eurasian Wigeon because the distinguishing marks are on the
>flanks, not on the head. Also, Green-wings tend to hunker down in
>dense vegetation more than wigeon, and do not feed openly on golf
>courses, etc., like wigeon, so oddball teal are not as easily picked
>out. At places like Blackie Spit on Boundary Bay, where large
numbers
>of Green-wings can be seen at close range, one or more Eurasians (as
>well as the occasional intergrade) can usually be found every winter.
>Nevertheless, this form remains much scarcer than the Eurasian
Wigeon.
>
> I believe that Michael Price, in the attached discussion quoted
by
>Eric Stahlfeld, is correct in concluding that virtually all
"Eurasian"
>Green-wings seen in B.C. and Washington are the widespread Old World
>subspecies, crecca, rather than the Aleutian form, nimia, which is
>supposed to be largely non-migratory.
>
>That's all for now!
>
>Wayne Weber
>Kamloops and Delta, B.C.
>wayne_weber at bc.sympatico.ca
>