Subject: Everett Waterfront, possible Slaty-back Gull
Date: Dec 3 21:31:32 1997
From: Christopher Hill - cehill at u.washington.edu



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