Subject: Gull Help (fwd)
Date: Jan 4 20:57:09 1995
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Subj: Help with gull identification, please

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From: Martin Meyers <meyersm at ROMEO.ECS.CSUS.EDU>
Subject: Help with gull identification, please
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Can anybody give me some advice on separating first-year Thayer's from
Glaucous-winged Gulls? I have studied most of the guides and specialty
identification books (Gulls, Seabirds, ..), and every time I think I have it
down pat, I have a day like today! Dozens of first year gulls at a distance
of about 20 feet, and I get really confused!

Today in the Sacramento, CA. area (Nimbus Dam fish hatchery, to be precise),
the hatchery was dumping dead salmon through a tube into the American River,
and the gulls were having the time of their lives. The first-winter Glaucous
Gull which has hung out along the river this winter was there, as were
numerous Herring Gulls and California Gulls. But the problem for me was the
Thayer's Gulls. I saw several obvious Glaucous-wings, with large, thich bills,
and big heads with sloping foreheads. And I saw a couple obvious Thayer's,
with cute little "dove-like" heads and thin bills. And then there were all
the others. Medium sized heads, sloping foreheads changing to rounded profiles
depending on how long I looked. The bills were thick, well, um, sort of not
too thick but not as thin as the obvious Thayer's (which, of course, had flown
away to avoid comparisons).

Nat. Geo. says that primaries are always darker than mantle in Thayer's, while
in G-W, they are the same color as mantle, but the range of variation in the
birds at Nimbus today did little to convince me of that distinction (and
that subject was discussed on birdchat previously, as well). And the
amount of mottling (speckling) in the plumages also seemed to run the gamut.

So, HELP!!!

Martin Meyers
meyersm at csus.edu
Sacramento (and Truckee), CA.