[Birdtalk] possible Iceland Gull update

Sat Dec 30 16:50:19 GMT 2006

Mark,

I read your post with interest because this is such a
fascinating bird.  While I haven't seen photos of many of
the birds reported as Icelands in UT in the past, I've
looked at photos of two of them and saw the last one myself
at Bountiful.  Neither of those were as Kumlien's-like as
this one.  The one at Bountiful was very pale and similar to
Iceland in overall plumage but was bulky and had a large,
thick bill.  Responses on ID Frontiers from west coast
birders with extensive experience suggested it was a hybrid
of some sort.  The 1999 bird photographed at Bear River is
interesting.  It has a petite bill and rounded head but the
bird looks quite thin, almost like it's starving.  Tertials
are pretty interesting, extensively white, but it has an
obvious solid brown tail band, typical of Thayer's but not
Iceland.  It's also important to note the date, March, when
gulls should be paler overall due to normal fading of
plumage.

The current bird has a thin bill and rounded head that fit
Kumlien's Iceland Gull (as well as Thayer's).  The primaries
have extensive pale edges with dark arrowhead markings on
the tips that would be unusual for Thayer's but fits
Kumlien's Iceland Gull.  The tertials have no solid dark
centers, they are mostly white with some dark bars, unusual
at best for Thayer's but typical for Kumlien's.  Also what I
can see of the tail is all wrong for Thayer's.  If more
photos show the tail to be white with dark bars and no solid
dark tail band, which is the impression I get from the
bottom photo on Tim's page, I don't think you can safely
call this bird just a light Thayer's regardless of location.
Indeed Bruce Mactavish, who has more experience with
Kumlien's than anyone and is very critical of out-of-range
Kumlien's Gulls, suggests it could be "a Thayer's x
Kumlien's hybrid, an extreme end Thayer's or a slightly
unusual Kumlien's ".  Is it more likely to be the extreme of
pale Thayer's or a slightly unusual Iceland?  Hard to say.
For an example of an Iceland Gull that's more Thayer's-like
than this individual take a look at this bird photographed
in St. John's, Newfoundland (the heart of the winter range
of Kumlien's Iceland Gull) by Bruce Mactavish
http://www.birdinfo.com/A_Images_I/IcelandGull_0014.html  It
has darker primaries with much less extensive pale edges,
extensive dark centers on the tertials and appears to have a
dark tail.  If this bird is an Iceland then clearly Tim's
bird is well within the range of variation for Kumlien's.

While it may not be accepted as a "good" Kumlien's Gull by
everyone, and maybe shouldn't be accepted by the Utah BRC,
it clearly is a contender and, in my opinion, is not just a
pale end Thayer's Gull.  That opinion could change if west
coast gull experts say that Thayer's can show the pale
tertials and tail shown by the Lee Kay bird.  However if it
can't be shown that Thayer's regularly shows such pale
tertials and tail it would be hard to see this bird as
anything but a Kumlien's.  I guess the question at that
point would be whether this bird is a "hybrid" Thayer's x
Kumlien's.  I'm not going there.  Whatever it is this is a
bird that's worth studying and documenting and hopefully
someone will get good in flight shots.  Congratulations to
Colby and Tim for finding this as well as the Western Gull.
I wish I could get down to see both birds there but it isn't
going to happen.  Maybe if they're still around in a couple
months?

Good birding.

Cliff

----- Original Message ----- 
From: "Mark Stackhouse" <westwings at sisna.com>
To: "Tim Avery" <tanager at timaverybirding.com>
Cc: "birdtalk Birds" <birdtalk at utahbirds.org>
Sent: Saturday, December 30, 2006 1:59 AM
Subject: Re: [Birdtalk] possible Iceland Gull update

| Hi Tim,
|
| This looks like any of several other contenders which have
been
| reported and photographed in recent years. The fact that
Iceland Gull
| still isn't on the Utah list tells you of the outcome of
all of these.
| An open-wing, open tail shot would help greatly, but we
may not ever be
| able to say for sure. There was a light Thayer's at the
Bountiful
| Landfill about 3 years ago that was even lighter than your
bird, but
| that showed markings supposedly diagnostic for Thayer's.
The opinions
| posted on Frontiers may reflect the location of the
commentator more
| than any feature of the bird itself. With intermediate
individuals like
| this, eastern birders would try to turn it into a Thayer's
| (unsuccessfully), while us westerners try to make it an
Iceland (also
| unsuccessfully). In other words, the bird is probably not
safely
| identifiable as one or the other, so the default is to the
common
| species of the area (Thayer's in the west and Iceland in
the east), and
| thus would be called something different depending upon
where it was
| seen. Since this is Utah, the "safe" call is a light
Thayer's. I do
| believe that we will someday have a "good" Iceland Gull
record in Utah,
| but we'll probably have to wait for a less intermediate
individual than
| this one.
|
| One thing that concerns me in particular about your bird
is the
| apparent darkish tips to the primaries. As I said, it
would be good to
| have better views of the tail and open wings. With regards
to the
| overall lightness of the bird, it appears to me to be
within the range
| of variation possible for Thayer's.
|
| Mark Stackhouse
| mark at westwings.com
| 801-487-9453 (Salt Lake City, Utah, USA)
| 011-52-323-285-1243 (San Blas, Nayarit, Mexico)
|
| On Dec 29, 2006, at 8:39 PM, Tim Avery wrote:
|
| > The ID frontiers list has been lighting up with
responses to the
| > pictures I have
| > posted. Many viewers believe this bird is inside the
normal range for a
| > Kumlien's type ICELAND GULL (not currently on the Utah
list).
| > However, others
| > insist that it is within the range for Thayer's Gull.
And yet other
| > insist
| > that this is likely an integrade and who knows???  For
anyone out
| > looking for
| > the Western Gull this weekend, keep your eyes peeled for
this very
| > light gull.
| > It basically looks like a tiny 1st winter Glaucous Gull,
but with an
| > all dark
| > bill.  If you have a camera try to get pictures of the
tail and any
| > open wing
| > shots in flight would be nice.  I will hopefully make it
out in the
| > afternoon.
| > Comments and pictures of this gull can be viewed here:
| >
| > http://timaverybirding.com/icgu/icgu.html
| >
| > Good Birding
| >
| > Tim
| > Indianapolis, IN and Salt Lake City, UT
| > tanager at timaverybirding.com
| > http://www.timaverybirding.com
| > http://www.birdtography.com
| > _______________________________________________
| > Birdtalk mailing list
| > Birdtalk at utahbirds.org
| > http://utahbirds.org/mailman/listinfo/birdtalk
| >
|
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