Gene Hunn, Seattle, hunnhome at accessone.com

Re. the 3rd year mystery gull. Wouldn't a 3rd year western have a more
streaked head? Isn't it just the adults that have the (nearly) immaculate
white head in winter? (Grant says the northern race of the Western has quite
a bit of streaking in winter, anyway.) Also, I'm confused about the
"distinctive" Slaty-backed underwing pattern. Just what is it supposed to
look like? My impression was that it lacked the well-defined black tips
under the wing, which, of course, the Western Gull also lacks, as sharply
defined black underwing tips is a feature of Herring Gull, etc. I had
concluded that this feature was used by those away from the West coast to
pick it out. Western Gull underwings are dusky but not sharply contrasting,
and the duskiness extends from primaries to the inner secondaries. In the
Slaty-backed Gulls I've seen I've not noticed anything particularly
different. The books say the Western outer primaries are blackish beneath,
those of Slaty-backed gray, but they don't distinguish southern from
northern Westerns, and in my experience our paler Westerns are dark gray
beneath, not "blackish." So it boils down to shades of gray beneath (which
is also subject to tricks of the light). The pale eye is not typical of
Western but does occur.

Signed: Confused in Seattle.



At 09:31 PM 12/3/97 -0800, you wrote:
>
>Took a cruise to the Everett 10th St. Boat Launch to look for the possible
>3rd year Slaty-backed Gull. Found it there, with Steve Mlodinow also
>there, having just exhausted his supply of Ritz crackers feeding it. I've
>never seen a bona fide Slatyback, let alone an immature, so this is
>presented for your perusal and feedback.
>
>The features on this one that suggest Slaty-backed are: Dark Mantle
>(darker than most local Western Gulls, but not much), combined with a
>heavily streaked head and light eyes. It also has large white tertial
>crescents for a third year bird. Most adult westerns that are anywhere
>near this dark have a nearly immaculate white head.
>
>I won't present a feather by feather description, but other features that
>stood out were:
>
>Body size: within the size range of the GWG/WG type gulls present,
>probably smaller than most of them.
>Bill: thick, mostly smudged with black, but with a yellow culmen.
>Tail: white with dark subterminal spotting on inner retrices
>Head: streaked longitudinally with dark gray, slightly darker under the
>eyes (but not dramatically so).
>Two or three tertial tips on each side (visible on the folded wing) were
>dark like the primary tips.
>
>Since it is not fully adult, though, it lacks white in the primaries, and
>I'm not sure how to evaluate the bird further. Could just be an unusual
>Western/Glaucous-wing hybrid, perhaps (or, as Steve suggested, it could
>also be a Slatyback-Glaucous-wing hybrid).
>
>I took about 15 pictures, trying in particular to document the underwing
>pattern.
>
>Also present were two of Everett's Black Ducks, and a blue morph Snow
>Goose.
>
>Chris Hill
>Everett, WA
>cehill at u.washington.edu
>
>
>
>