ID-FRONTIERS for February 1-9, 2002

Messages are displayed in the order they were received.  Subject  From  Date   Time   Continuing Red-necked Grebe & white bodied D.C. Cormorant   Bob & Carol Yutzy    Sat, 2 Feb 2002   10:51pm   mystery goose   Michael Retter    Sun, 3 Feb 2002   4:05pm   Re: 1B HERG with molted wing coverts?   Annika Forsten    Mon, 4 Feb 2002   1:39am   More on poss. Glaucous-winged Gull in Ohio   hein prinsen    Tue, 5 Feb 2002   10:50am   Re: More on poss. Glaucous-winged Gull in Ohio   Phil Pickering    Tue, 5 Feb 2002   2:41pm   Re: poss GWGU, Ohio   hein prinsen    Tue, 5 Feb 2002   4:13pm   More comments on Glaucous-winged Gull, Ohio   hein prinsen    Tue, 5 Feb 2002   8:43pm   Re: poss GWGU, Ohio   Martin Reid    Wed, 6 Feb 2002   6:52am   possible GW Gull in Ohio.   Alvaro Jaramillo    Thu, 7 Feb 2002   11:02am

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Subject: Continuing Red-necked Grebe & white bodied D.C.
         Cormorant
From: Bob & Carol Yutzy <boby(AT)C-ZONE.NET>
Date: 2 Feb 2002 10:51pm

Today we easily found the apparently single remaining RED-NECKED GREBE
at Brandy Creek Marina, Whiskeytown Lake, off 299 West out of Redding.

The bird was to the right of the island just off the boat ramp area
between the first white buoy marker and the island.  This is just where
it was seen on Jan. 31 by Jan and John Coon.

There were also two adult BALD EAGLES atop the pines on the opposite
shores of the lake.

What was also quite interesting was the WHITEST BODIED DOUBLE-CRESTED
CORMORANT I can remember seeing with 4 or 5 other D.-C. Cormorants.
There was a variety of whitish and spotted upper breasts on the other
Double-crested like I'm used to seeing.  But this one bird which stood
on the white buoys was dark above and VERY CLEAN WHITE below from the
LOWER FACE TO AT LEAST THE AREA BELOW THE FEET!  Sibley mentions the
juveniules can be variably white below to almost clear white and the
first volume of the advanced Audubon Guide clearly states that it
occurs.  But I don't remember seeing it before!

Anyone have any insight on this.

Bob & Carol Y.


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Subject: mystery goose
From: Michael Retter <mretter(AT)HOTMAIL.COM>
Date: 3 Feb 2002 4:05pm

Hello all,

I've been studying a goose here in Bloomington, IL the last few days.
Although my best guess is Ross' X Richardson's (Branta canadensis
hutchinsii), I still cannot positively identify it.  Your input is greatly
appreciated!  Discussion and pictures are at
http://www.iwu.edu/~mretter/strange_goose.htm

----------
Michael L. P. Retter
Illinois Wesleyan University
Bloomington, McLean Co, IL
mretter(AT)iwu.edu
http://www.iwu.edu/~mretter

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Subject: Re: 1B HERG with molted wing coverts?
From: Annika Forsten <annika.forsten(AT)FI.INTRUM.COM>
Date: 4 Feb 2002 1:39am

Martin Read wrote:

>  As a student of gulls, I feel that Steve Howell and Chris Corben have
>helped make significant advances in our understanding of molt in large
>gulls, especially the awareness that molt is a continuous process, and the
>timing of a feather's replacement can make it look very different from
>others replaced in the same "wave" but at a different time; thanks, guys.
>However, if I've understood them, the process of continuous molt is not
>uniform across all tracts.  In Europe it seems common practice to use the
>presence of 2nd-generation wing coverts on 1CY/2CY birds up to about their
>first February or March as a means of locating michahellis among
>argentatus/argenteus.
>  The premise of this approach is that HERGs do not
>start to replace their first-generation wing coverts until their first Spring.
>Am I interpreting this correctly?

Yes, but this also occurs in argentatus. In Finnish Herring Gulls it is
quite rare however, with only about 0.1% doing this. And only a very few
moult more than c. 3 coverts.

So moulted wing coverts is still a good reason to give the bird close
scrutiny, but in no way a definite field mark.

>There seems to be recent evidence that some juvenile LBBGs in Holland
>acquire some 2nd-generation wing coverts at a very early stage (e.g. still
>being attend by adults).  Do these birds then suspend wing-covert molt
>until the Spring? Do michahellis suspend their wing covert molt (they can
>replace none, to almost all wing coverts, in the Fall), or molt them
>continuously through the winter?

This seems to be dependant on how cold it is, ie. the location where the
bird spends its winter, and of course on where and how it migrates. There
is much variation, but in general Herring Gulls in Finland for example
suspend moult from November to February.

>its implications (if any) on how we use molt in trying to identify gulls -
>thanks.

Never say never concerning anything to do with identifying gulls.

annika


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Subject: More on poss. Glaucous-winged Gull in Ohio
From: hein prinsen <hprinsen(AT)HOTMAIL.COM>
Date: 5 Feb 2002 10:50am

All:

After posting a possible Glaucous-winged Gull in Ohio (see January 26th and
discussion afterwards) the same bird has been seen by several observers.
Greg Miller observed the bird on Jan. 29th and posted a field sketch and
documentation on his web site:

http://members.self-serv.net/hawkowl/HuronGull.html

After studying more literature and gull material on the web, I completely
agree with Greg's statement that "this bird is either a good glaucous-winged
gull or at the very least, a glaucous-winged gull x herring gull hybrid
which approaches all the characteristics of the glaucous-winged gull".

Most of the comments I received (thanks all!!) on the pics on my web site
(www.umich.edu/~hprinsen/gulls.htm) also point to this direction (I hope to
compile these comments on my web site asap). However, so far I haven't
received or found any good documentation on adult winter plumage GWGU x HEGU
hybrids. Is there anybody out there (west coast birders?) with good pictures
or descriptions to share??

best wishes,

Hein Prinsen
Ann Arbor, Michigan

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Subject: Re: More on poss. Glaucous-winged Gull in Ohio
From: Phil Pickering <philliplc(AT)HARBORSIDE.COM>
Date: 5 Feb 2002 2:41pm

Forgive me if this is excessive posting, but I wanted to expand
a little on previous points made on the Ohio gull. I can't say it
isn't a pure Glaucous-winged, but in my opinion there are a few
things about it that are atypical enough to be quite worrisome,
and at least leave open the possibility that it is not pure. It is
true that GWs are extremely variable, but the vast majority
have a look that is not shared by the Ohio gull. This is not what
you would want if hoping for a first state record.

Most troublesome is the head shape. In my experience GWs,
even smaller birds, usually have a fairly long, flat forehead without
a break in angle out much in front of the eye. They also average a
fairly shallow forehead/bill angle, and typically have a rounded
crown with a peak about mid-crown, or even a little forward. The
Ohio gull's head shape is very strange. The majority of the crown
seems to slope forward, quite steeply at the fore-crown. There is
also a strange, very low break in angle between fore-crown and
forehead that is well out in front of the eye. This seems quite
atypical for GW to me, even when they are facing into wind and
their crown feathers are flattened. The overall head shape doesn't
really fit anything that I can think of, suggesting hybridization. Hybrids
can show a mix of structural characteristics as well as plumage
features, and sometimes seem strangely shaped or proportioned.

The bill also seems odd. It is thicker, but doesn't really seem that
much longer than the Ring-billed. It also looks like it could be
fairly straight to me. Perhaps those who saw it in person can
clarify, but it looks like the bill might be cracked open slightly
in all three posted head shots. This would make it seem thicker
than it is, particularly at the tip, and would tend to overemphasize
the apparent gonydeal angle (a sort of optical illusion). If this is
the case, it also at least would hint at the possibility that the bill
could have a slight genetic deformity, perhaps also indicative of
hybridization. Again, this bill shape/size is not necessarily outside
the range of Glaucous-winged, but it seems to be far enough from
typical to me to leave doubt.

Perhaps the photos are misleading, but the darkness of the primaries
also looks borderline to me, most evident in the definition and contrast
of the mirrors on the underside. How dark can the primaries of "pure"
Glaucous-winged (from anywhere) be? Hybridization and back-
crossing with Western and Herring (and apparently also Slaty-backed)
have created a continuous cline in primary shade, as well as other
features. Latent introgression has probably made this situation too
complex for a simply answer to that question anyway.

Perhaps I'm being too picky, but from a BRC perspective I'm not
sure how you could prove that a gull like this is a GW, given its
apparently atypical features (IMHO). Interesting bird.

Cheers,

Phil


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Subject: Re: poss GWGU, Ohio
From: hein prinsen <hprinsen(AT)HOTMAIL.COM>
Date: 5 Feb 2002 4:13pm

Some comments to Phil Pickering's concerns:

a) I didn't notice anything peculiar about the bill, such as it being
'cracked' open or deformed. My description, mainly based on the video,
reads: "Bill blunt-tipped and straight, relatively thick but not very long
(and not drooping). No conspicuous gonydeal angle. In the field we noted
that the bill did not differ much from surrounding Herring Gulls, except it
seemed somewhat thicker". In fact, this was the main reason we believed at
the time that it was probably not a GWGU. Several people have, however,
pointed out that bill structure of GWGU is very variable.

b) Contrary to PP and the description of Greg Miller, I found that the
primaries were the same light gray color as the upperparts (which we thought
were similar in gray to surrounding Herring/Ring-billed Gulls). From certain
angles it looked as if the outer primaries were a tint darker gray than the
inner primaries. Note, however, that we observed the bird under bright sunny
conditions and that on the video the primaries are mainly in the shadow.

If this bird is not better documented (and studied in flight!) it might
indeed be difficult to prove its ID.

Hein Prinsen
Ann Arbor, Michigan

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Subject: More comments on Glaucous-winged Gull, Ohio
From: hein prinsen <hprinsen(AT)HOTMAIL.COM>
Date: 5 Feb 2002 8:43pm

Those who are still following the discussion on the possible Glaucous-winged
Gull in Ohio might be interested in a summary of comments that I have
received to date. I have also included my description of this bird.

www.umich.edu/~hprinsen/gulls.htm

Hein Prinsen
Ann Arbor, Michigan

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Subject: Re: poss GWGU, Ohio
From: Martin Reid <upupa(AT)AIRMAIL.NET>
Date: 6 Feb 2002 6:52am

Dear Hein and all,
Most interesting feedback on this bird!  Looking at all the comments, and
looking at the photos and descriptions again, I feel that this bird APPEARS
TO BE so close to GWGU that it becomes a matter of degree and reasonableness.
Frankly, I don't think that getting much better photos will move the ID
forward at all - unless they show this bird at the same angle in good light
to a selection of HERGs and RBGUs, such that the true mantle shade can be
objectively assessed. You already have enough photo evidence to establish
all the other good and contentious features.

To me the niggles on this bird are:
1) mantle color may not be dark enough for classic GWGU, given your
description that it was similar to HERG/RBGU (contra Gregory's notes): I
think that most GWGUs look clearly a half+  shade darker than HERG/RGBU -
more like nominate CAGU.
2) bill and head structure (and brightness of bill) are not classic, and
appear closer to HERG than most GWGUs.
3) size is towards the small end for GWGU.

None of the above are exclusionary for GWGU, and it is possible that those
in GWGU-land could show us photos of a bird or two that is nearly identical
to this one (no two gulls are actually identical!)  - but we must then ask
the question (given that GWGU-land is also Hybridland) - can we be sure
what the comparison birds really are???
One could take an absolutist view, and say that a State First should be
unequivocal - "there are lots of classic GWGUs out there that are large,
darker-mantled, with bigger bills; let's wait until we document one of
these".  This approach is bolstered by the apparent evidence that most
claimed GWGU candidates east of the Rockies seem to be similarly very
small, with a troubling collection of minority GWGU features.
But, maybe most of these vagrant birds are from an unlocated population
that averages smaller, daintier, and a tad lighter-mantled? - again the
next question must be "but does this population reflect introgression from
HERG?".
So is a:  "GWGU" that has no wrong features, many right ones, but a few
that are only seen in a minority of presumed GWGUs in their normal range -
acceptable as a first State record? what about a 2nd or 3rd State record??
I don't know the answer to this, and I'd have to ponder over it quite a bit
if I were on a RBC reviewing this bird.... This individual is right up to
the pure GWGU "line", but is it touching it?
We may face this philosophical chestnut with other gull taxa (e.g. vegae;
imm. schistisagus; imm. Azorean atlantis); a similar debate surrounding
thayeri and kumlieni has been aired, but that one is further muddied by
even greater taxonomic uncertainty.
Good luck!
Martin

At 2/6/2002 12:13 AM +0100, you wrote:
>Some comments to Phil Pickering's concerns:
>
>a) I didn't notice anything peculiar about the bill, such as it being
>'cracked' open or deformed. My description, mainly based on the video,
>reads: "Bill blunt-tipped and straight, relatively thick but not very long
>(and not drooping). No conspicuous gonydeal angle. In the field we noted
>that the bill did not differ much from surrounding Herring Gulls, except it
>seemed somewhat thicker". In fact, this was the main reason we believed at
>the time that it was probably not a GWGU. Several people have, however,
>pointed out that bill structure of GWGU is very variable.
>
>b) Contrary to PP and the description of Greg Miller, I found that the
>primaries were the same light gray color as the upperparts (which we thought
>were similar in gray to surrounding Herring/Ring-billed Gulls). From certain
>angles it looked as if the outer primaries were a tint darker gray than the
>inner primaries. Note, however, that we observed the bird under bright sunny
>conditions and that on the video the primaries are mainly in the shadow.
>
>If this bird is not better documented (and studied in flight!) it might
>indeed be difficult to prove its ID.
>
>Hein Prinsen
>Ann Arbor, Michigan
>
>
>
>_________________________________________________________________
>Chat with friends online, try MSN Messenger: http://messenger.msn.com

Martin Reid
Fort Worth, Texas
upupa(AT)airmail.net
http://www.martinreid.com


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Subject: possible GW Gull in Ohio.
From: Alvaro Jaramillo <chucao(AT)HOME.COM>
Date: 7 Feb 2002 11:02am

Birders,

   Just a quick comment here. If I saw this gull here in California right
now, I would not call it a (pure) Glaucous-winged Gull. I live right on the
ocean and see thousands of these guys all winter, including hundreds of
hybrids and other weirdos. I try to be conservative in identifying GWGU as
I know I am surrounded by hybrids here. Structurally this thing looks too
small billed (both in length and depth at gonys), small-headed, and
generally too small. Even small Glaucous-winged Gulls are big.
Glaucous-winged Gulls are large-billed, large-headed, small-eyed, long
necked creatures. The posture of the Ohio bird just doesn't look right for
GWGU to me.

Other points that bother me:
- bill colour on the bright side for a winter GWGU. A bright yellow bill
and little head streaking on a GWGU type bird here is seen as a sign of
Western Gull genes.
- mantle looks too dark, with more contrast with tertial crescent than on
typical GWGU.
- lack of head smudging and "barring" on neck odd for a January GWGU.
- am I imagining things, or is the outer primary still growing? That alone
is bad for GWGU.
- Primaries too dark for pure GWGU.
- wing pattern odd. Underwing shows one clear, large mirror on p10, and
apparently a small mirror on P9. Usually its rather difficult to study the
wing pattern of GWGU since the dark parts of the primaries are so pale. The
fact that you can see the mirrors this clearly in a photo taken through the
scope is a point against GWGU. Also GWGU shows a smaller P10 mirror, and
none on P9 (usually??).
- white primary tips too small on this bird, they are larger on typical GWGU.

This thing is not a Thayer's gull either; the wing pattern alone rules that
species out.

I think we are talking about one of the many hybrid possibilities. Its
become less and less fun to guess on putative parents of hybrids, given
that we are often not dealing with F1 hybrids and we really don't have
much, or any, information on what some of these hybrids will look like from
known parental type mixes.

I hate being the party pooper, but thought I would put out my thoughts as
they did not match with what others were saying.

cheers,

Alvaro Jaramillo
chucao(AT)home.com
Montara, California

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