[Tweeters] 1st Winter SB Gull

SGMlod at aol.com SGMlod at aol.com
Sat Dec 11 21:08:55 PST 2004

Greetings All

Today Kevin Aanerud, Jessie Barry, and I had an apparent Slaty-backed Gull at
the Cedar River mouth.

This bird was, shall we say, a hold-on-to-your-hat-and-pray-you're-right kind
of bird. It was pretty close and we watched in excellent light from about
2-3pm. Lotsa video was shot. My arm and thumb still hurt. Call it Gull Video
Tendinitis. I think I'll write it up for the medical journals.

It was a 1st year gull with the following features:

1) size and body structure of GW or Western Gull (that is, big bodied and
short winged)

2) entirely dark brown tail, excepting very narrow pale terminal band

3) medium gray back with anchor/triangle shaped marks within each feather

4) From underside, wingtips showed dark on only outer two or three feathers.
This was limited to feather tip only, and only the outer two showed any dark
at all on inner web. In flight, the underwing closely resembled a first-winter

5) From above (unfortunately, bird did not preen so as to give us detailed
primary exam from above) wings showed and extensive pale panel that extended
well onto the outer primaries. Only the outer 2 primaries appeared mostly dark.
The others appeared mostly light with a dark spot near each feather's terminus.

6) perched, the wing coverts were dark brown with small crisp white spots,
including the greater coverts.

7) the tertails were plain and brown; unmarked and paler than the folded

8) the folded primaries were dark brown, but paler than nearby first year
Herring Gulls. Small pale edges were present on each primary.

9) the bill was Herring Gull in shape, though a bit stubbier. Some pale at
base unevenly distributed.

10) mostly white headed and dark eyed.

11) Contrasting white rump with scattered dark bars/spots

Confused. Don't feel bad. Looking at a number of sources, the variability of
even 1st winter gulls is bewildering.

This bird definitely looked different. The primary pattern was more like
Thayer's than Herring (fitting SBGU well, especially with those dark dots at the
ends of the primaries in flight). The all dark unmarked tail combined with a
white rump fits SBGU. Herring Gulls should show some barring at the tail base.
Herring Gulls should have pale greater coverts with dark marking rather than
vice versa and the tertials should be somewhat marked. The bird's shape was
great for SBGU and unlike Herring. The bill was more Herring like, but within
range of SBGUs shown in the Princeton gull book and on the Ujihara's Japanese Gull
site http://larus.hp.infoseek.co.jp/gullidentifi_.htm

Nothing was wrong for SBGU and several marks eliminate or point against
Herring Gull, Thayer's Gull, and yes, Vega Gull.

So, for those brave of heart....

Best Wishes
Steven Mlodinow
Everett WA

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