[Tweeters] Sunday Bob sighting

Eugene and Nancy Hunn enhunn323 at comcast.net
Mon Jan 12 11:22:43 PST 2009


**If you have tired of this debate, just press the delete button now.



John,



Thanks for the photos and the discussion of "Bob."



A few points of clarification. From my reading and consideration of the
measurements published in Olsen and Larsson and Howell and Dunn nominate
Iceland and Kumlein's are indistinguishable by size for any of the standard
measurements. According to a systematic study reported in Howell and Dunn of
over 300 adult "Kumlein's" gulls in Newfoundland, 5% showed apparently pure
white wing-tips. Were these "white-winged Kumlein's" or nominate Iceland. As
far as I can judge the two options are indistinguishable and perhaps it is a
meaningless distinction, since we don't know where these wintering birds
bred and since nominate-phenotype Iceland's could very well breed within
Kumlein's range. There is clearly a perfect cline bridging the
Kumlein-nominate Iceland divide. The distance between western Greenland and
Baffin Island is not very far and both types have been photographed in
Japan. The eye color ought to correlate with the primary color. As for eye
ring color, Marv Breece's head shot of "Bob" from 2006 clearly shows a dark
eye ring contrasting with the yellow iris. I've not been able to determine
if it is red or purple. In any case, Glaucous is supposed to have yellow to
orange eye ring, not red, except perhaps in the odd individual.



As for size or bulk, male Iceland, like male Thayer's, broadly overlap at
least Herring Gull in most measurements, with the exception of bill length
and tarsus, in which case Iceland (Kumlein's and nominate) scarcely overlap
barrovianus Glaucous females. Some observers seem to be looking for the
small extreme of Iceland, i.e., females. As the name "Bob" implies, he is
most likely a male. Nevertheless, as a proponent of Iceland for Bob, I judge
that he falls more readily within the range of proportions of Iceland than
of Glaucous. It seems to me that many of your Kumlein's photos and those
posted on the Japan gull site match Bob's head and bill very nicely.
Certainly, the Glaucous immature with Bob you photographed is what I would
consider typical of Glaucous, much longer billed, bulkier, and flatter
crowned, contrasting dramatically with "Bob."



Also several of your photos of Bob show the position of the wings and tail.
On one at least the primaries appear to project at least the bill length
beyond the tail tip. Though, as you note, and as I have noted, photos of
Glaucous and Iceland vary considerably as to the apparent primary tip
projection (beyond the tail) so as to make this distinction quite difficult
to determine objectively. It probably depends a lot on momentary postural
shifts.



Gene Hunn

18476 47th Pl NE

Lake Forest Park, WA

enhunn323 at comcast.net



From: tweeters-bounces at mailman2.u.washington.edu
[mailto:tweeters-bounces at mailman2.u.washington.edu] On Behalf Of John
Puschock
Sent: Sunday, January 11, 2009 10:35 PM
To: tweeters at u.washington.edu
Subject: [Tweeters] Sunday Bob sighting




Hi,

Bob was in his field on 212th St. in Kent this afternoon (11 Jan 2009)
between 12 and 2 PM. An unequivocal immature Glaucous Gull flew in around
1:30, too. I put some photos at http://www.zbirdtours.com/bob.htm

I have to say I'm still in the Glaucous camp. Bob's head appears to be more
rounded than a typical Glaucous, and overall he/she is on the small side,
but I don't think either feature is too extreme for Glaucous, while both are
outside what I'd expect for an Iceland. The body looks bulkier than I'd
expect on an Iceland, particularly around the lower breast. Also, the eye
looks to be relatively small in relation to the size of the head, and it
also may be placed too far forward for an Iceland. Since the primary tips
are all white, the light was poor, and Bob was pretty far away, I couldn't
say for sure where the tail tip was in relation to the primaries, but I got
the impression that there was not much extension of the primaries beyond the
tail. I'll admit that the distance from the tertials to the longest primary
tip looks fairly long, but I'm be more interested in figuring out where the
tail tip is in relation to the primaries. (Note that Nat'l Geo. shows
primaries barely extending beyond the tail in Glaucous, but photos in Howell
and Dunn's Gulls of the Americas show a longer extension on several birds.
Sibley also appears to be more generous than Nat'l Geo.)

The eyes appear to be paler than what's typical for a Kumlien's Iceland
Gull, and of course, the white primary tips are relatively rare on
Kumlien's. Also, I've heard (but haven't seen for myself) that the orbital
ring is red, while Kumlien's typically have a purplish ring. Of course, red
isn't the "standard" color for Glaucous either, but all of my reference
material mention it for that species. However, nominate Iceland Gulls have
pale eyes and red orbital rings according to what I've read. Some books
mention that subspecies as being the same size as Kumlien's while Sibley and
the Nat'l Geo. say that the nominate form averages smaller than Kumlien's.
In either case, Bob strikes me as being too large, and as I mentioned,
he/she looks too bulky and the size and positioning of the eye looks wrong
for an Iceland of either subspecies. Bob's head looks pretty similar to the
"small adult" Glaucous shown in the bottom right corner of page 220 in the
big Sibley.

Anyway, that's just my opinion. I'm still willing to be convinced
otherwise. A look at photos 35.B3 and 35B.4 in Howell and Dunn should take
away certainty. I've sent some photos to a couple people in Newfoundland,
and I'll post something if I hear anything more definitive from them.

I apologize if all of this has been covered in previous years.

Just a reminder, I have photos of Kumlien's Iceland Gulls at
http://www.zbirdtours.com/icelands.htm

John Puschock
Wedgwood, Seattle
g_g_allin at hotmail.com
http://www.birdtreks.com & http://www.zbirdtours.com

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