Friends--during a visit to the Olympic Peninsula last summer I took the
opportunity to study <italic>brachyrynchus </italic>Mew Gull at the mouth
of the Elwa River. I'm now writing to inquire about differences between
Mew Gull <italic>L. canus brachyrynchus </italic>(hereafter, MEGU) and
Common Gull <italic>L. canus canus</italic> (hereafter, COGU).


Sorry for the pedantry. But here in the east it's very important to
make the distinction, especially since the popular field guides send
people out looking for your bird, the Mew Gull, a great rarity, rather
than Common Gull, of Western Europe, the bird we can usually count on
seeing hither and yon, mostly in winter.


I'll preface my queries with remarks on Common Gull for people who have
no experience with it. My queries concern adults only. I don't ask
about patterns in the outer primaries, a subject to which I would like to
return later.


<bold>Bill shape, size, coloration</bold>.


The numerous summer adult MEGU at Elwa impressed me as having much
smaller bills than the 12-15 winter COGU of all vintages I've studied in
Massachusetts, some at very close range for several weeks. The MEGU
bills appeared to be vertically thinner and shaped like pegs. That is,
the upper mandible paralleled the lower. By contrast, the COGU I've seen
presented upper mandibles thicker than lower, and noticeably down-curved
at the tip.


<underline>Question</underline>. Is there a difference in bill shape and
size?


In winter, adult COGU very frequently presents a black bill tip or a
black smudge at the tip of the bill (but not a
<italic>well-defined</italic> ring). For years, our local heaviest of
the heavies told people the bird had to be a Ring-billed Gull (RBGU).
Some of us fought him off. He doesn't give out that misinformation
anymore.


Since he's super conservative, let's assume he had also been mislead by
the popular field guides and was thinking not of COGU but of your bird,
MEGU.


<underline>Question</underline>. Does winter adult MEGU present black at
the tip of the bill, on either or both mandibles, or is the adult bill
<italic>always</italic> a clear yellow?


<bold>Tone of back</bold>.


I had been led to expect that MEGU would be noticeably darker on the
back than RBGU and also darker than COGU. I have been underwhelmed by
the difference in tone between the the latter two birds in Mass. I was
also underwhelmed by the difference in tone with the MEGU and RBGU at
Elwa.


Maybe something's wrong with my dark/light perception. The California
Gulls at Elwa didn't strike me as noticeably darker than the RBGU
either.


<underline>Question</underline>. Was I >>not<<<< seing things? Just
how would you all describe the difference in the tone of the back between
MEGU and RBGU?


<bold>Length of wings.</bold> COGU appears longer-winged than RBGU,
when both are standing on the ice, beach etc., but the wings of the MEGU
at Elwa appeared even longer; indeed, the MEGU there appeared
considerably more graceful than most the COGU I have seen.


<underline>Question</underline>. Can anyone address the issue of
overall proportions? Is MEGU generally a more aesthetically elegant
bird?


I'll conclude now, for the moment, hoping to continue this discussion
later.


Yours,


Jim Barton

redwing1986 at mediaone.net

Cambridge, MA