Re Wigeons & stuff

Dennis queries the occurrence of mated Eurasian Wigeons (EUWI) in the
region. An experience here in Vancouver BC may be helpful.

First, it helps to know that, south of Alaska, the bay between the Roberts
Bank Coalport and Tsawwassen Ferry Terminal Jetties is the North American
capital for EUWI. On a given winter day, the large waterfowl flocks there
(large concentration of tens of thousands of Mallard, wigeon, pintails,
both scaups, all three scoters, teal, Brant) contain between 35 and 60
males alone. In spring, presumably when EUWI from further south migrate up
and join the local flocks, the accumulation has been known to top--no
lie--*150* males! At least three credible observers saw this flock (though
the local gods had some trouble accepting the number) and and several times
in subsequent years *pure* flocks approaching it in size have been seen
since. Another mixed wigeon flock containing *147* males alone was seen
during a freeze-up in late winter. No count was made of any females which
may have been present. In other locations besides the Ladner area (the
jetties, Reifel & Westham Islands), numbers are much more 'normal': 1 or 2,
occasionally 3, males per location. At any given time in a normal winter, I
would make a horseback guess that there are between 30 & 50 males at all
other locations combined in the Vancouver BC area. These large
concentrations seem to occur only during freeze-ups which drive them into
fields, or in the northbound migration. Either way, ain't rare here.

In March, 1993, I was helping a birder from Oz pick up some lifers, when we
found 19 EUWI at the Roberts Bank Coalport Jetty. Three were single
definitive males, 16 were in 8 pairs, each at the shoreline, spaced
regularly about 150m apart--that's 8 prs in less than a mile; on a jetty
close to 3 miles long, that would suggest, if the distribution was
consistent, 32 prs. Each pair seemed to be feeding but there was more an
air of, well, couples in a small, dark restaurant than dabbling ducks
slurping up sea lettuce. A distinct air of--can it be said?--foolin'
around. That's not counting the probably-equal to more numerous birds in
the offshore flocks. Each female was rufous-morph. Lack of time prevented a
full survey of the entire shoreline or the large offshore flocks. Hm. Just
wondering, after re-reading this, if that 150m separation is consistent
with the separation between nesting pairs on the breeding grounds. Anyone
know?

Over the years, my personal experience (such as it is) is that females are
more numerous than supposed, and their absence is more likely an artefact
of observer coverage than actual dearth. As N. American observers have
pointed out, the difficulty in female EUWI field ID posed by the
'grey-morph' female is formidable; also, as Gene Hunn has pointed out, some
birds tentatively identified as 'rufous-morph' females in the early part of
the southbound migration late Sept. to mid-Oct. may be, in fact, both
juvenile and eclipse-plumage males.

It's gonna take a few years of pretty dedicated flogging of the wigeon
flocks to figure out the proper migration dynamics (i.e., avg arrival in
Vancouver BC, Oct. 2; avg departure, April 19), total numbers per winter,
average ratio-per-AMWI, male-to-female and adults-to-young ratios. Michael
Price
Vancouver BC Canada
michael_price at mindlink.bc.ca