Mike, when you say short primary projection, have you ruled out
feather wear? That is, the primaries appear to be full length and do
not appear to be short because they are worn down? [I don't have the
pictures in front of me, so ask simply for completeness]
Regards, Laurie.
On 23/02/2008, at 5:08 PM, Mike Carter wrote:
Nikolas Haass <> said today
To: "Tony Russell" <>; "Mike Carter" <
>; "BIRDING-AUS" <>
Although I was the first one who dared to ID the bird as a female
first-winter Slaty-backed Gull (see old posting below), I still
would NOT say that we 'SETTLED' on a definite ID.
We clearly ruled out Thayer's Gull, American Herring Gull (see
below), the fuscus complex including Heuglin's Gull (heuglini and
taimyrensis), Eurasian Herring Gull, and most of the "yellow-legged
gull complex". Moreover, as I indicated a week ago, tail and
primary patterns speak against Mongolian and Steppe Gull.
And also Vega doesn't fit 100%. But - although it was my favorite -
does Slaty-back fit 100%? No, it looks good for a Slaty-back, but
apparently not 100%! Look at all the divergent comments from
experts from all over the world! I think, the final ID at this
point should be "possible Slaty-back".
Nikolas
So although you named it several days ago, you are still not 100%
convinced?
Please tell us what you consider unsatisfactory in that ID.
Jeff Davies and I will prepare the BARC submission and we are
confident that we can totally justify that diagnosis. Among
significant aspects that you didn't address were the plain dark
underwing pattern and short primary projection beyond tail. Once
those two features fell into place for Slaty-backed ruling out Vega
Gull the one remaining stumbling block was the scapular pattern
which was more typical of Vega Gull. But now we know some Slaty-
backs can be similarly patterned there are no contra-indications.
The presence of that second generation secondary feather noted by
Alvaro was a bonus. All discriminators are in favour of Slaty-backed
Gull. QED.
Mike Carter
30 Canadian Bay Road
Mount Eliza VIC 3930
Tel (03) 9787 7136
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