Tweeters,



Dennis Paulson has hit the nail on the head in pointing out the dramatic
differences in habitat preference and feeding ecology between Mew Gulls and
the larger species (Glaucous-winged, Thayer's, Ring-billed, etc.). One very
obvious difference, not mentioned so far, is that Mew Gulls are virtually
NEVER seen attempting to feed in landfills and garbage dumps, which are the
main source of food ( at least in southwestern BC) for Glaucous-wings. If
Mew Gulls did try to compete in the rough-and-tumble of landfills with the
much larger and more aggressive Glaucous-wings, they wouldn't last a day.



Mew Gulls do the vast majority of their feeding in two habitat types: (1)
in offshore tide-rips, where they often feed in pure or near-pure flocks,
and (2) in grassy fields and pastures. In the latter situation, I see Mew
Gulls feeding most often in pure or near-pure flocks, although sometimes
mixed with smaller numbers of larger gulls such as Thayer's and
Glaucous-wings. I often see, after a rainfall, mixed flocks of Mew Gulls and
Thayer's, but with no Glaucous-wings. Mew Gulls don't seem to be intimidated
as much by Thayer's as by the even bigger and meaner Glaucous-wings.



Where Mew Gulls and Glaucous-wings do feed in mixed flocks, the latter are
usually in the minority, and the flocks are often so spread out that it's
easy for the Mew Gulls to avoid the Glaucous-wings (e.g., to capture and
swallow a worm before a Glaucous-wing has a chance to steal it.)



It's interesting to consider where Bonaparte's Gulls fit into the picture.
Like Mew Gulls, they do most of their feeding around offshore tide-rips
(e.g. high-current areas like Active Pass, BC, or off Point No Point or
Point Roberts), or on intertidal mud flats at low tide (Semiahmoo Bay is a
good example of this). However, they almost never feed in fields and
pastures (and NEVER in garbage dumps), thereby avoiding much potential
competition with both Mew Gulls and the larger gulls.



So it may not be accurate to say that Mew Gulls NEVER frequent parking lots
and similar habitats in the Puget Sound area, but in my experience, it's
certainly the exception rather than the rule. Mike Munts' observation that
Mew Gulls are commonly seen around parking lots in the Yukon-- where they
are the only common

gull-- only seems to underline the axiom that the feeding preference of
gull species for different feeding habitats is driven to a large degree by
interspecific competition. This agrees with what one would expect from
ecological theory.





Wayne C. Weber

Delta, BC

contopus at telus.net





From: tweeters-bounces at mailman1.u.washington.edu
[mailto:tweeters-bounces at mailman1.u.washington.edu] On Behalf Of Dennis
Paulson
Sent: March-19-12 10:28 AM
To: TWEETERS tweeters
Subject: Re: [Tweeters] Mew Gull's Don't



Well, maybe we have incontrovertible evidence that Mew Gulls in Everett
don't like parking lots. At least in the last few years. ;-)



Dennis





On Mar 19, 2012, at 9:07 AM, Mike M wrote:





You guys may be interested that when I was in the Yukon a few years ago I
regularly saw Mew Gulls in parking lots. They were often in flocks of
several hundred to over a thousand and are the only common gull in the area
when I was there mid-summer.



Mike

Colville



From: Michael Hobbs <mailto:BirdMarymoor at frontier.com>

Sent: Thursday, March 15, 2012 12:23 PM

To: Dennis Paulson <mailto:dennispaulson at comcast.net> ; TWEETERS tweeters
<mailto:tweeters at u.washington.edu>

Subject: Re: [Tweeters] Mew Gull's Don't



At Marymoor Park, all winter long, there is almost always a flock of Mew
Gulls (50-400 typically) that comes in and feeds on the grass soccer fields
just after sunrise, staying for 0.5-4 hours depending on the day. There are
almost always Ring-billed and Glaucous-winged Gulls mixed in with them,
feeding side by side. I've never noticed any aggression between the
species - they're all just walking fairly close together across the grass
feeding on worms and grubs.



We haven't had the large flocks of Mews for the last few weeks, but today
there were about 25 gulls present, mostly sticking together, that included
at least 1 Mew Gull, along with a couple of Ring-billed, 2+ California, a
Herring Gull (very unusual for Marymoor), and the rest Glaucous-winged and
Glaucous-winged x Western Hybrids



== Michael Hobbs
== Kirkland, WA
== http://www.marymoor.org/birding.htm
== http://www.marymoor.org/BirdBlog.htm
== birdmarymoor at frontier.com



From: Dennis Paulson <mailto:dennispaulson at comcast.net>

Sent: Thursday, March 15, 2012 8:29 AM

To: TWEETERS tweeters <mailto:tweeters at u.washington.edu>

Subject: Re: [Tweeters] Mew Gull's Don't



Jeff,



One reason might be because Mew Gulls are deathly afraid of the larger
species. It is a rare roost, in any habitat type, that contains both Mew and
Glaucous-winged. For years I have been looking for a photo op of both of
them standing together, and it still hasn't happened. I don't know if big
gulls would actually try a predation attempt or if they represent a source
of potential kleptoparasitism that is so guaranteed that the small gulls
just stay away from them. I don't even have a photo of the two flying
together, although I've been alert for that as well.



They also don't eat the same things. Mew Gulls do not come to thrown bread,
although everything else from Ring-billed size up does so, also Laughing
Gulls in the East. But not Bonaparte's, not Franklin's, and not Mew.
Probably not kittiwakes either, but I haven't had the pleasure of testing
that hypothesis. But not being stimulated to feed on the same things, maybe
roosting together isn't appropriate.



Now you're going to say that Mew Gulls still don't roost in parking lots
even when there isn't a big gull in sight, and I've got no glib answer to
that. They do roost on grass fields, plowed fields and sandy beaches, but
maybe their little feet are just too delicate for the tarmac. They also
roost on gravel beaches, but I don't recall if I have seen them on solid
rock substrates like where you see a lot of Heermann's and kittiwakes, as
well as large gulls, roosting on the outer coast. Maybe the parking lot just
looks like a rock substrate, and that's not where they rest.



There's another tweeters challenge - find and document Mew Gulls on a
parking lot!



Dennis



"Big gulls don't cry."--Fergie.





On Mar 14, 2012, at 11:26 PM, jeff gibson wrote:





Mew Gull's don't seem to like parking lots. Up here in Everett the 10th
street boatlaunch parking lot, several acres of tarmac, is often full of
parked gull's of most of the white-headed varieties. Mostly Glaucous-wings
(and hybrids) and Ring-billed, along with occasional California, Herring,
Thayer's, Heerman's, or Glaucous, depending on season. And in season
Caspian Terns also park out there. But just about never a Mew.
I can't say they won't, but Mew's just don't seem to be the parking type.
Immediately North of the parking lot are the tidal 'maulsby mud-flats'.
Plenty of Mew Gull's out there in Winter, only yards away sometimes, from
the parking lot. It does seem that there's more of them congregated near
freshwater rivulets on the North side of the flats, if that means anything,
but then all the other gull's are out there with them.



The lot being a popular human gull-feeder spot, possibly there's some gull
union action going on that Mews aren't members of, like the "United
White-head's for White bread" union. Whateverett.



Jeff Gibson

Everett Wa

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-----

Dennis Paulson

1724 NE 98 St.

Seattle, WA 98115

206-528-1382

dennispaulson at comcast.net