Path: utzoo!utgpu!attcan!uunet!seismo!sundc!pitstop!sun!decwrl!labrea!rutgers!att!whuts!picuxa!gpasq
From: gpasq@picuxa.UUCP (Greg Pasquariello X1190)
Newsgroups: rec.birds
Subject: Re: Trip to Mass.
Message-ID: <693@picuxa.UUCP>
Date: 2 Nov 88 18:19:15 GMT
References: <691@picuxa.UUCP> <31830@oliveb.olivetti.com>
Reply-To: gpasq@picuxa.UUCP (Greg Pasquariello X1190)
Organization: AT&T/EDS Product Integration Center
Lines: 66

In article <31830@oliveb.olivetti.com> mjm@oliven.olivetti.com (Michael Mammoser) writes:
>In article <691@picuxa.UUCP>, gpasq@picuxa.UUCP (Greg Pasquariello X1190) writes:
> > 
> > But the best bird came as we were headed back to port.  It was
> > with the other gulls, and was very probably a Thayer's gull.  I managed to 
> > see the bird quite well, and it had many of the characteristics of the
> > Thayer's. 
>
>	Two weeks ago I was out at the Bay and found the first Thayer's of the
>season; 6 birds in a flock of Western, Herring, and California Gulls.
>
>	Thayer's is intermediate in size and structure between Herring and 
>Iceland. The mantle is slightly darker than on Herring and obviously darker
>than on Iceland. Compared to Herring, the bill is smaller and the head is
>rounder, giving the bird a more "gentle" appearance; although not to the extent
>it is on Iceland. Thayer's will have a dark eye, which may be only a brown-
>flecked yellow, but never entirely pale like Herring. The legs may be a deep
>rose-pink or purplish-pink, where Herring and Iceland have pale pink legs.
>The black on the wing-tips is not as extensive as on Herring. The black is
>limited to the outer webs of the primaries except at the very tips of the
>feathers. When the wings are fully spread, the effect is of black and white
>lines on the wing tip (similar to the wing tip pattern for the Kumlieni race
>of Iceland Gull, except the Kumlieni has a frosted gray color and not black
>like Thayer's). The underwings are pale silvery with dark tips to the primaries.
>
>Good luck,
>Mike


Thanks for the tips.  Do you have any for the pre-adult birds?  The one we
saw in Mass was a second winter bird, with a somewhat gray mantle, back, 
and wings.   The tips (on top) were a dusky grey-brown, the underwing tips
were pale (see exception below) and the bird was generally paler than a
herring gull of the same age.  The rump was whitish (a fairly good mark),
and the tail was brown with a dark brown terminal band.  The head was pale.

Some of the exceptions that make me hesitate in calling it a Thayer's include:

	1.	The bill was that of a herring gull, not any more delicate.
	2.	The jizz wasn't right.  Color aside, it _looked_ like a 
		herring gull.
	3.	The eye was yellow.  All literature says it ranges from 
		brown to yellow flecked with brown, but Wayne Peterson
		says it can be clear yellow (true?).
	4.	There were no dusky ear coverts.
	5.	The outer 2 primaries were duskier than the inner ones,
		giving an impression of somewhat darker tips.
	6.	It was the size of a herring gull.

I am of the opinion that it may be a Herring x Glaucous hybrid.  I read
last night (I think in Harrison's seabirds) that 50% of the Glaucous gulls
in (hmmm, where was it... Iceland maybe?) are hybrids, and that in some
locations there are almost no pure glaucous.

I believe all of the large Larus gulls (of the "herring gull type") should
be lumped.

Thanks again Mike!

Happy Birding.
Greg
-- 
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"I crush your head!"		Greg Pasquariello   AT&T PMTC
				att!picuxa!gpasq    Parsippany, NJ
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