ID-FRONTIERS for April 1-5, 2003

Messages are displayed in the order they were received.  Subject  From  Date   Time   Fw: Great Gull   Norman D.van Swelm   Tue, 1 Apr 2003   12:14pm   Re: Fw: Great Gull   Bert-Jan Luijendijk    Tue, 1 Apr 2003   2:22pm   Primary molt in Franklin's Gull   Martin Reid    Tue, 1 Apr 2003   7:32pm   Franklin's Gulls and P10   Michael Donahue    Tue, 1 Apr 2003   9:59pm   Re: Fw: Great Gull   Norman D.van Swelm   Wed, 2 Apr 2003   6:38am   Arctic National Wildlife Refuge   Alan Wormington    Wed, 2 Apr 2003   10:19am   Re: Fw: Great Gull   Bert-Jan Luijendijk    Wed, 2 Apr 2003   11:38am   Re: Fw: Great Gull   Norman D.van Swelm   Wed, 2 Apr 2003   2:34pm   Don't forget...   Michel Bertrand    Wed, 2 Apr 2003   2:36pm   Re: Fw: Great Gull   Peter Adriaens    Wed, 2 Apr 2003   5:35pm   Re: Fw: Great Gull   Bert-Jan Luijendijk    Thu, 3 Apr 2003   12:50am   Re: Fw: Great Gull   Dick Newell    Thu, 3 Apr 2003   6:04am   Re: Fw: Great Gull   Alvaro Jaramillo    Thu, 3 Apr 2003   12:44pm   Re: Fw: Great Gull   Martin Reid    Fri, 4 Apr 2003   5:19am   Re: Fw: Great Gull   Peter Adriaens    Fri, 4 Apr 2003   8:27am   Re: Fw: Great Gull   Martin Reid    Sat, 5 Apr 2003   7:22am   Re: Fw: Great Gull   Norman D.van Swelm   Sat, 5 Apr 2003   11:24am

To use email addresses replace '(AT)' with '@'. This is done to confuse the spam 'bots.

[ << | >> | ^^ ]

Subject: Fw: Great Gull
From: "Norman D.van Swelm" <Norman.vanswelm(AT)WXS.NL>
Date: 1 Apr 2003 12:14pm

I have here a most interesting response by Fréderique Jiguet and he has
allowed me to share it with you.
Norman

>I have been asked by Pierre-André Crochet to give an opinion on the "gull
a"
presented on Martin at Reid's site.

  http://www.martinreid.com/gullsp32.html

To define its identity, we first should clinch about the age and the moult
stage, which I think you already did. For example, a suspected bird in
French Guyana this winter was in primary moult by January-February, had dark
on front of tarsi, and correct structure for Kelp, and is to my opinion a
good Kelp. I have not so much experience with vetula, and Ian Sinclair wrote
most of the text concerning this subspecies in our paper in
Birding World. The best would be to get his opinion on this bird, as the
subspecies display some differing variations around the common
'species-specific' patterns cited in the paper.

You are right to mention that the southern Indian Ocean populations are
particular, and these were
recently elevated to subspecific rank (Jiguet 2002, a paper published in
Bull.B.O.C.). A young Kelp or Cape Gull with pink legs is of course
possible, but now let's go back to your bird. From photo experience, I would
say that Cape Gull is more likely to show pink legs than the others,
and also to show such a large bill already at this age. You might confirm my
impression, please:
This bird seems to end its primary moult, with the P9-10 not fully grown, as
P8 seems to be the longest outermost primary. The tail, tertials,
scapulars and most of the mantle feathers have been moulted and are not
juvenile feathers any more (except for a few mantle feathers). The large
tarsi and legs, the large bill are in favour of Kelp/Cape Gull, as does the
moult stage if this bird is effectively moulting outer primaries. I did not
know before that this bird was photographed in November, but this is an
important point when interpreting the moult stage! This bird is obviously
in its first-year or one-year old, and a northern hemisphere gull would not
show such an advanced moult stage, and it is difficult for me to make of
this gull a 2-y old with retarded moult, dark eye and all dark bill, and
some retained juvenile mantle feathers! The greater coverts pattern seems
completely OK for Cape, while the tail pattern would be at the palest
extreme but within the range of all subspecies (even for Kerguelen Gull).
The 'pale' grey (not slate black) colour of the new mantle feathers is also
not a problem for such a 1-y old Kelp / Cape, as it is often the rule.

Well, I think it is worth getting the opinion of observers used with the
vetula subspecies, and I would be very interesting to hear from their
comments!

NB: the first record of Cape Gull for France has recently been  accepted by
the French Rarities Committee (see the latest 'Ornithos'), and was added to
category D waiting for more information on the occurrence pattern of the
species in Europe.
I observed the adult Cape Gull (ssp vetula) in Paris in January 1995. The
bird was first left unidentified, and this was the beginning of my interest
for this particular gull species. Ian definitely identified this bird as a
vetula, and the description and photos were sent to the French RC, who
accepted the record. A picture appeared in the last 'Ornithos'
 A as yours might come directly from the south
(the Paris' gull was on a northern moult cycle, so was probably in the
northern hemisphere for a long time, as is observed in the USA, with
immatures often on a southern, adults on a northern moult schedule).

The Crozet/Kerguelen/Marion/Heard birds are named 'judithae', the Malagazy
Gull 'melisandae', and I proposed to resurrect the name 'austrinus' for the
antarctic birds. The work is still going on, to maybe identify new
subspecies in e.g. south america, new zealand, etc...

The young bird from French Guyana is the one, I think. it was actively
moulting outer primaries (moult end) in a set of photos taken in February.
The plumage was overall very 'juvenile'. Your bird has mostly moulted, and
this is more reminiscent of vetula to my eyes, which seems to be able to
moult earlier (see the pics in the Birding World paper).

Best wishes,
Frederic Jiguet


[ << | >> | ^^ ]

Subject: Re: Fw: Great Gull
From: Bert-Jan Luijendijk <bjluijendijk(AT)PLANET.NL>
Date: 1 Apr 2003 2:22pm

Frederique Jiquet wrote:

>This bird seems to end its primary moult, with the P9-10 not fully grown,
as
>P8 seems to be the longest outermost primary. The tail, tertials,
>scapulars and most of the mantle feathers have been moulted and are not
>juvenile feathers any more (except for a few mantle feathers). The large
>tarsi and legs, the large bill are in favour of Kelp/Cape Gull, as does the
>moult stage if this bird is effectively moulting outer primaries. I did not
>know before that this bird was photographed in November, but this is an
>important point when interpreting the moult stage! This bird is obviously
>in its first-year or one-year old, and a northern hemisphere gull would not
>show such an advanced moult stage, and it is difficult for me to make of
>this gull a 2-y old with retarded moult, dark eye and all dark bill, and
>some retained juvenile mantle feathers!

There are several things in the above stated comments by Frederique Jiquet,
which I can't follow. The first remark I wish to make, is that all visible
tertials, upperwingcoverts, rectrices and primaries (at least up to P8) are
i.m.o. second generation feathers. I find it normally very difficult to
determine different feathergenerations in the mantle and scapular region but
I am rather sure neither feathertract contains any juvenile feather and most
probably consists of either 2nd generation (older ones) and some 3rd
generation feathers (fresh ones), or 3rd generation (older ones) and 4th
generation (fresh ones) - depends mainly on the timing of the replacement of
the juvenile feathers.
It is beyond doubt a northern hemisphere gull would not show such an
advanced moult stage in November of its 1st year. Since the bird does not
show any juvenile feathers and has nearly accomplished its complete
(post-breeding) moult, I belief we are dealing with a gull in its 2nd cy
(2nd year) from the Northern Hemisphere (with the latter I am ahead of next
alinea).

My second point is that unlike Frederique seems to suggest, I don't think th
at the moultstage shown by Gull A fits a gull originating from the southern
hemisphere. After all 1st year Kelp Gulls from this part of the world should
start their complete moult  -that is what I read in Jiquet et al's article
in Birding World- during September to December and finish this moult during
February to April of their 2nd year (see also Plate 8-10 of 1st year Kelp
Gulls in December and January). Taking this into account I would be very
surprised if any 1st year Kelp Gull from the Southern Hemisphere in November
would be in an equivalent stage of the complete moult as Gull A, unless you
argue that it might have adjusted its moulttiming to northern
hemisphere-standards (but given its age this might not be a very likely
explanation). In case Gull A would be a Kelp Gull - and as you may know, I
don't support that view- I would argue for a 2nd year Kelp Gull originating
from the Northern Hemisphere. With reference to the large gulls breeding in
Europe, the level of delay in terms of moult is limited and falls within the
range of moulttiming of most large gulls (including Greater Black-backed
Gulls L. marinus) occuring at this continent.

In an earlier posting Norman van Swelm wrote:

> However anyone who has
> studied L.marinus knows that a plumage like that of gull a is unknown in
> L.marinus. Even in it's third winter L.marinus does not have a dark band
> formed by the greater coverts as gull a has.

I suggest you read my comments in response to Peter Adriaans' statement that
Gull A might miss a large amount of greater upperwingcoverts. In that mail I
tried to explain why the appearance of the greater coverts is dark.
Furthermore, I do not share your opinion that "there is no European gull
that has this combination of feather generations". In my view, the exposed
upperwingcoverts consists of the same generation (2nd) and any differences
in wear/bleaching are mainly caused by differences in timing and/or rate of
featherreplacement.

On basis of moult and plumage characteristics I still belief Gull A
originates from the Northern Hemisphere and is most probably a 2nd cy/2nd
year Greater Black-backed Gull.

Cheers, Bert-Jan Luijendijk


[ << | >> | ^^ ]

Subject: Primary molt in Franklin's Gull
From: Martin Reid <upupa(AT)AIRMAIL.NET>
Date: 1 Apr 2003 7:32pm

Dear all,
Following up on my earlier post on this subject, I have now been able to
look at more than 200 FRGUs at my local site in the past two weeks.  All
but a handful appeared to have been adult-types (complete black hood,
strong - but variable - pink wash to chest; mostly large white apical
primary spots.)  I'd estimate that between 50% and 70% of the total had at
least one retained older-generation primary.  I'd estimate that only
about  20% - 35% of the total  had P10 with an extensive white tip; one is
tempted to consider that these are the true adults while the remainder are
"not-yet-adult" - but to me this ratio seems wrong given the expected pool
of adults in any Spring gull population; perhaps migration timing is
age-biased, but my recollection is that  subadults tend to be more frequent
later in the season - ?
Here are fifteen more birds from this site/period (I also have pics of
about ten more individuals):
http://www.martinreid.com/frgu04.html
  - points of interest:-
It is much harder to see the condition of the tips of P10 on birds where
this tip is extensively white; I saw a couple that clearly were fresh, and
at least two such birds where P10 was older-generation (e.g. bird j) );
most of the individuals of this class were left as indeterminate.
At least two individuals appeared to have a fresh P10 plus P7-5, while
having older P8 & P9 (e.g. bird i) ) - ?
Bird d) shows clear signs of immaturity (white speckles in head; brownish
tinges to some scaps and wing coverts) - yet it seems to be one of the
minority of birds with no older-generation primaries.
Bird l) - one of only two first-Spring birds I've seen at this site so far
this Spring - appears to have primaries of a single generation (P10 may be
slightly more worn, but this may be within the norm for the leading-edge
feather.)

FYI here's the first page on this subject:
http://www.martinreid.com/frgu03.html

- and here are a few birds that must have just arrived on their wintering
grounds (or did some never leave?), revealing some interesting molt
patterns; all my comments therein remain speculative!:
http://www.martinreid.com/frgu05.html

I have heard from Steve Howell that FRGUs were late arriving at their
wintering sites along coastal Chile this past Winter; Steve speculates that
this may have been influenced by El Nino, and also that poor winter feeding
conditions could have had a systemic effect on the energy-expensive
business of primary replacement.
So, are the birds I've been studying this Spring representative of normal
years, or not?
Cheers,
Martin

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


[ << | >> | ^^ ]

Subject: Franklin's Gulls and P10
From: Michael Donahue <mgd(AT)U.WASHINGTON.EDU>
Date: 1 Apr 2003 9:59pm

This is a multi-part message in MIME format.

----INCLUDING text/plain MIME SECTION----

Martin,
In June of 2002 I spent a couple of days at Benton Lake NWR in central =
Montana. I found a roadkill Franklin's Gull, and was surprised that all =
but P10 had been replaced. (I have a photo of the spread wing if you're =
interested.) I now wish I had spent more time looking at Franklin's Gull =
primaries! Maybe the El Nino had an impact on molt this past season, but =
I wanted to point out that I had seen this same thing (albeit sample =
size of 1) in 2002.

Mike Donahue
Seattle

----DELETED text/html MIME SECTION----


[ << | >> | ^^ ]

Subject: Re: Fw: Great Gull
From: "Norman D.van Swelm" <Norman.vanswelm(AT)WXS.NL>
Date: 2 Apr 2003 6:38am

Bert-Jan Luijendijk wrote:
> In an earlier posting Norman van Swelm wrote:
>
> > However anyone who has
> > studied L.marinus knows that a plumage like that of gull a is unknown in
> > L.marinus. Even in it's third winter L.marinus does not have a dark band
> > formed by the greater coverts as gull a has.

> I suggest you read my comments in response to Peter Adriaans' statement
that
> Gull A might miss a large amount of greater upperwingcoverts. In that mail
I
> tried to explain why the appearance of the greater coverts is dark.
> Furthermore, I do not share your opinion that "there is no European gull
> that has this combination of feather generations". In my view, the exposed
> upperwingcoverts consists of the same generation (2nd) and any differences
> in wear/bleaching are mainly caused by differences in timing and/or rate
of
> featherreplacement.<

> On basis of moult and plumage characteristics I still belief Gull A
> originates from the Northern Hemisphere and is most probably a 2nd cy/2nd
> year Greater Black-backed Gull.<

Correct me if I am wrong Bert-Jan but I can see two generations in lesser-,
median and greater coverts: worn juvenile ones and new feathers. No immature
Great Black-backed Gull would show this in November! "Gull a" does not miss
any greater covert and if it did it would still be alien to immature Great
Black-backed Gull in November. All immature Great Black-backed Gulls have
finished moulting these feathers long before November. Besides there is no
plumage like this one in Great Black-backed Gull. It seems to me you have
not seen the pictures of Kelp Gull in the Birding World article of Kelp in
similar plumages. I 'd be happy to send you a copy. I can understand your
confusion very well BTW!
Norman
Norman


[ << | >> | ^^ ]

Subject: Arctic National Wildlife Refuge
From: Alan Wormington <wormington(AT)JUNO.COM>
Date: 2 Apr 2003 10:19am

Request for Info:

My apologies for this off-topic request, but several months ago I read a
posting somewhere about someone's trek on foot through the Arctic
National Wildlife Refuge, and his detailed reasoning why the location
should not opened for drilling.

If anyone can direct me to the original account, it would be most
appreciated.

Alan Wormington
Leamington, Ontario


[ << | >> | ^^ ]

Subject: Re: Fw: Great Gull
From: Bert-Jan Luijendijk <bjluijendijk(AT)planet.nl>
Date: 2 Apr 2003 11:38am

Hi Norman and others,

> Correct me if I am wrong Bert-Jan but I can see two generations in
lesser-,
> median and greater coverts: worn juvenile ones and new feathers. No
immature
> Great Black-backed Gull would show this in November! "Gull a" does not
miss
> any greater covert and if it did it would still be alien to immature Great
> Black-backed Gull in November.

It looks that we can finally reach an agreement in one respect ;-): Gull A
does not miss greater upperwingcoverts and as far as I can see I think this
gull does not miss upperwingcoverts or tertials at all.

Concerning your statement that you can see "two generations in lesser-,
median and greater coverts: worn juvenile ones and new feathers", I wish to
remark the following in addition to my earlier comments:
I do not doubt that the worn feathers in the inner part of the greater
coverts, median coverts and (especially) lower row of the lesser coverts are
older than the fresh ones you can detect in the remaining part of the
greater coverts and in the upper region of the lesser coverts. But my point
is that this apparent difference in age is probably not caused by different
feathergenerations but by differences in the timing/sequence and rate of
renewal (of feathers of the same generation) between and within particular
parts of the upperwingcoverts. One should never forget that these
differences can be substantial. To give you an example with respect to the
greater upperwingcoverts: the inner ones are up to 2 months earlier acquired
than the central ones! When I look at the wingcoverts of Gull A, it is
evident to me that these feathers and rows which are relatively abraded and
bleached are these featers and rows which are typically renewed in an
earlier stage of the complete moult than the fresh-looking feathers. If you
wish, I can go much further into this matter.

> Besides there is no
> plumage like this one in Great Black-backed Gull. It seems to me you have
> not seen the pictures of Kelp Gull in the Birding World article of Kelp in
> similar plumages. I 'd be happy to send you a copy. I can understand your
> confusion very well BTW!

In case you mean the article "Identification of Kelp Gull" by Frederic
Jiquet, Alvaro Jaramillo and Ian Sinclair in Birding World 14: 112-125 I can
assure you that I am in receipt of this article since it appeared in April
2001 and I have consulted both text and pictures several times in during
this discussion (anyway thanks for your kind offer). Sofar I have not
managed to find the pictures you are referring to, which should show Kelp
Gulls with a similar plumage and similar moultstage at a similar time of the
year - or am I missing something?

As I have already expressed my opinion on the id of Gull A and I try to
repeat myself not too often, I will not comment on your claim that there is
no plumage like Gull A in Greater Black-backed Gull. Instead I will be very
polite towards you tonight :-) by assuming Gull A is a Kelp Gull of less
than one year old and then ask you the following: how do you explain (taking
the time of the year and current knowlegde of the moult of Kelp Gulls into
account) the apparent moultstage or -in a broader sense- moulttiming of the
primaries of (Kelp)Gull A? - besides Norman, is there perhaps someone else
who can comment on this question?

Cheers,
Bert-Jan Luijendijk


[ << | >> | ^^ ]

Subject: Re: Fw: Great Gull
From: "Norman D.van Swelm" <Norman.vanswelm(AT)WXS.NL>
Date: 2 Apr 2003 2:34pm

Bert-Jan Luijendijk wrote:> In case you mean the article "Identification of
Kelp Gull" by Frederic
> Jiquet, Alvaro Jaramillo and Ian Sinclair in Birding World 14: 112-125 I
can
> assure you that I am in receipt of this article since it appeared in April
> 2001 and I have consulted both text and pictures several times in during
> this discussion (anyway thanks for your kind offer). Sofar I have not
> managed to find the pictures you are referring to, which should show Kelp
> Gulls with a similar plumage and similar moultstage at a similar time of
the
> year - or am I missing something?<
I have referred to plate 13, page 117. The bird portrayed there looks very
much like "gull a". The photo was taken in March. I think "gull a",
photographed in the first week of November will look quite the same as the
bird in plate 13 five
months on!

Bert-Jan Luijendijk also wrote:> As I have already expressed my opinion on
the id of Gull A and I try to
> repeat myself not too often, I will not comment on your claim that there
is
> no plumage like Gull A in Greater Black-backed Gull. Instead I will be
very
> polite towards you tonight :-) by assuming Gull A is a Kelp Gull of less
> than one year old and then ask you the following: how do you explain
(taking
> the time of the year and current knowlegde of the moult of Kelp Gulls into
> account) the apparent moultstage or -in a broader sense- moulttiming of
the
> primaries of (Kelp)Gull A? - besides Norman, is there perhaps someone else
> who can comment on this question?<
I cannot answer your question as I have no experience with Kelp Gulls.
However, I have an awfull lot of experience with Great Black-backed Gulls,
one of the reasons why I know "gull a" is not one of them.
Norman


[ << | >> | ^^ ]

Subject: Don't forget...
From: Michel Bertrand <bertrmi(AT)COLBA.NET>
Date: 2 Apr 2003 2:36pm

Was it your intent to answer QuébecOiseaux quiz 26 ?
If you still haven't sent your identification, don't forget
that April 5th is the last day for sending it.

I have already received almost 200 answers and I can
say that you are far fom being unanimous about the
ID of the actual mystery bird. You can see it in the
magazine or, on Internet, at the address given at the
end of this message.

Good luck...

     MICHEL BERTRAND
     Sainte-Julie, Qc
     bertrmi(AT)colba.net

N'oubliez pas d'identifier l'oiseau mystère :
Don't forget to identify the mystery bird at :
http://www.quebecoiseaux.qc.ca/HTML/Defi.html


[ << | >> | ^^ ]

Subject: Re: Fw: Great Gull
From: Peter Adriaens <peter.adriaens(AT)DUTCHBIRDING.NL>
Date: 2 Apr 2003 5:35pm

Hi,

>> Correct me if I am wrong Bert-Jan but I can see two generations in
lesser-
>> median and greater coverts: worn juvenile ones and new feathers. No
>>immature
>>Great Black-backed Gull would show this in November! "Gull a" does not
miss
>> any greater covert and if it did it would still be alien to immature
Great
>> Black-backed Gull in November. All immature Great Black-backed Gulls have
>> finished moulting these feathers long before November. Besides there is
no
>> plumage like this one in Great Black-backed Gull. It seems to me you have
>> not seen the pictures of Kelp Gull in the Birding World article of Kelp
in
>> similar plumages.

Norman,
a good example of a late autumn 2cy Great Black-backed Gull with obviously
ongoing moult in the wing-coverts can be seen on Mars Muusse's website:
http://www.birdsnaps.com/gbbg/gbbg2cy/gbbg2cy20.htm
This bird was ringed as a pullus in Denmark. The photo was taken on 22
October, so I am not sure if the "law" you proclaim that "all immature
Great Black-backed Gulls have finished moulting these feathers LONG before
November", holds true for this Danish bird at least.

I am certainly not familiar with Kelp Gull, but when I look at the Birding
World article, it seems clear that:
a) primary moult should only start by early November, not finish (if the
bird is on a southern Hemisphere cycle). You refer to plate 13 on p. 117;
that bird indeed has a primary moult score similar to yours, only 5 months
later!
b) The new, fresh second-generation primaries do not normally have obvious
white tips. This is to be expected in any large gull in which the adults
have only small or average white primary tips. Second winter Yellow-legged
Gulls, Lesser Black-backed Gulls, argenteus Herring Gulls, etc. have only
thin pale edges on the primaries, not contrasting white tips as on your
bird (e.g. on p4-5). However, such white tips are a regular sight in 2nd
winter GBBGulls -- reflecting the large white tips of the adults.
All of the 2nd winter Kelp Gulls featured in the article (including the one
on plate 13) show, in fact, all-dark primaries; it is even hard to detect
pale edges in most of these birds.

You say that you have looked at lots and lots of Great Black-backed Gulls,
and I certainly believe you. You say that this 'gull A' struck you as very
different from any of them, and I can believe that too. But that does not
make it something from the southern Hemisphere yet.

Best regards,
Peter


[ << | >> | ^^ ]

Subject: Re: Fw: Great Gull
From: Bert-Jan Luijendijk <bjluijendijk(AT)planet.nl>
Date: 3 Apr 2003 12:50am

Hi Norman and others,

> I have referred to plate 13, page 117. The bird portrayed there looks very
> much like "gull a". The photo was taken in March. I think "gull a",
> photographed in the first week of November will look quite the same as the
> bird in plate 13 five
> months on!

And what about the reverse Norman? Suppose the Kelp Gull portrayed in plate
13 would have been photographed in November, do you think it would have
looked the same as gull A?

Much has already been said by Peter, but as "Kelp Gull 13" has the same
moultstage in March as Gull A in November and one takes into account what is
stated in the paper about the duration of the complete moult in Kelp Gulls,
I am affraid that the appearance of Kelp Gull 13 in November was much like
the Kelp Gull portrayed in Plate 8 of the same article.

And indeed, hypothetically, and as said earlier, a Kelp Gull originating
from the Southern Hemisphere and appearing in the Northern Hemisphere might
fit its moulttiming to the standards of the latter region. But:
1a) as long as this scenario has not been proven yet*;
1b) immature Kelp Gulls turning up in the US seems to follow the same
moultttiming as gulls from the Southern Hemisphere (as noted by Frederic
Jiquet in his second comment);
2) this gull appears to show characteristics which are not always associated
with Kelp Gulls;
3) taking the extremely rare occurence of Kelp Gulls on the western shores
of the WP into account,
I would really hesitate to call Gull A a Kelp Gull.

*Alvaro Jaramillo has written several postings on this subject and if you
wish to read more about the effect of photoperiod on moult, I can strongly
recommend the following interesting paper (based on experimental research):
Lesher, S W & Kendeigh, S.C. 1941. Effect of photoperiod on molting of
feathers. The Wilson Bulletin 53: 169-180.

This was my last post on the subject "gull a".

Cheers, Bert-Jan Luijendijk


[ << | >> | ^^ ]

Subject: Re: Fw: Great Gull
From: Dick Newell <dick.newell(AT)MACUNLIMITED.NET>
Date: 3 Apr 2003 6:04am

re:  http://www.martinreid.com/gullsp32.html - Gull a)

I have avoided getting drawn into casting an opinion on this bird, because I
don't know.
However, arguments about moult timing should acknowledge that Kelp Gulls
(vetula?) breed in the Northern Hemisphere in Senegal and Mauretania (I
don't know when). So 2 Kelps 6 months apart could quite possibly look
similar in terms of moult.
I must say that, although there are some similarities with the bird referred
to in Plate 13 (BW Vol 14 No 3 page 117), there are at least as many
differences.
For a Kelp Gull, I would prefer it if there were a picture somewhere which
showed rather more resemblance to Norman's bird. To me, plate 9 (right hand
bird on the same page) has rather more similar scapulars and wing-coverts.
Gull a) is very odd-looking for a GBBG - and apparently rather small. But
there are plenty of very odd-looking gulls around of all forms.
One of the commonest hybrids in Holland must be graellsii x michahellis -
some things tempt me towards this e.g. size, eye-shadow, stout bill, but I
cannot really make it fit.
As I said, I just don't know, but to me, Kelp Gull is not eliminated yet.
Dick Newell, Cambridge, UK


[ << | >> | ^^ ]

Subject: Re: Fw: Great Gull
From: Alvaro Jaramillo <chucao(AT)ATTBI.COM>
Date: 3 Apr 2003 12:44pm

At 09:49 AM 4/3/2003 +0200, Bert-Jan Luijendijk wrote:
>Hi Norman and others,
>
>And indeed, hypothetically, and as said earlier, a Kelp Gull originating
>from the Southern Hemisphere and appearing in the Northern Hemisphere might
>fit its moulttiming to the standards of the latter region. But:
>1a) as long as this scenario has not been proven yet*;
>1b) immature Kelp Gulls turning up in the US seems to follow the same
>moultttiming as gulls from the Southern Hemisphere (as noted by Frederic
>Jiquet in his second comment);

Most (if not all?) Kelp Gulls reported from North America have been adults
or nearly so. I don't think that any younger age stages have been reported.
Most Kelp Gulls reported from the US have been those which have bred in
Louisiana, and as far as I know these were on a northern hemisphere moult
schedule.

>I would really hesitate to call Gull A a Kelp Gull.

Just for the record, in my opinion Bird A looks nothing like a South
American or Antarctic Kelp Gull. I realize that you folks are thinking of
the African form, but one could develop a pretty clear argument against a
South American Kelp Gull for this bird.

regards

Alvaro

Alvaro Jaramillo
Biologist
San Francisco Bay Bird Observatory
P.O. Box 247
Alviso, CA 95002
(408)-946-6548
http://www.sfbbo.org/
chucao(AT)attbi.com


[ << | >> | ^^ ]

Subject: Re: Fw: Great Gull
From: Martin Reid <upupa(AT)AIRMAIL.NET>
Date: 4 Apr 2003 5:19am

Dear all,
I too have held off from commenting on this bird, but now that Dick has
added some more valuable commentary and data, I'll contribute a some snippets.
Dick asked for a pic of a Kelp closer to Norman's bird - how about this one?:
http://www.martinreid.com/kegup04.html
  - obviously the date is three months apart, but given that African Kelp
(vetula) seems to have a huge latitudinal breeding range, I don't think it
is wise to dismiss this as a Kelp mainly because of molt timing.  Presuming
for a moment it is a Kelp, we have no idea when it moved into the Northern
Hemisphere (indeed in may have ALWAYS lived there!); I feel that the main
reason that vagrant records of Kelp al virtually all adults/subadults is
that younger birds are extremely hard to ID and are being missed/discarded.
I would also draw your attention to plate 6 in the Jiguet et al Article
reference in previous emails on this matter.  This  juvenile is from Feb
(Boreal equivalent would be August) - yet it is extremely abraded; I doubt
that this individual was born in South Africa - more likely from somewhere
further north (is there any evidence of Kelp migration within
Africa?)  Anyway, compare the structure and bare parts to Norman's Gull;
vetula seems to have a squared-off rear crown, unlike most other forms of
Kelp; the legs are a perfect match for Norman's gull, and I wonder if any
age of GBBG shows the combination of greenish-gray tibia plus pale flesh
tarsi that have dark bars of the front?  So presuming that, like other
large gulls of the Northern Hemisphere, some first-summer Kelps will molt
from a long-retained juvenile plumage into a 2nd-winter plumage, I wonder
if the gull in Plate 6 could soon look a lot more like Norman's gull?
I want to make it clear that I am not saying that Norman's gull is a Kelp -
rather I am agreeing with Dick that Kelp is not ruled out at this point -
plus the legs look pretty good for a vetula Kelp and take some explaining
for a GBBG.
Cheers,
Martin

At 4/3/2003 02:02 PM +0100, you wrote:
>re:  http://www.martinreid.com/gullsp32.html - Gull a)
>
>I have avoided getting drawn into casting an opinion on this bird, because I
>don't know.
>However, arguments about moult timing should acknowledge that Kelp Gulls
>(vetula?) breed in the Northern Hemisphere in Senegal and Mauretania (I
>don't know when). So 2 Kelps 6 months apart could quite possibly look
>similar in terms of moult.
>I must say that, although there are some similarities with the bird referred
>to in Plate 13 (BW Vol 14 No 3 page 117), there are at least as many
>differences.
>For a Kelp Gull, I would prefer it if there were a picture somewhere which
>showed rather more resemblance to Norman's bird. To me, plate 9 (right hand
>bird on the same page) has rather more similar scapulars and wing-coverts.
>Gull a) is very odd-looking for a GBBG - and apparently rather small. But
>there are plenty of very odd-looking gulls around of all forms.
>One of the commonest hybrids in Holland must be graellsii x michahellis -
>some things tempt me towards this e.g. size, eye-shadow, stout bill, but I
>cannot really make it fit.
>As I said, I just don't know, but to me, Kelp Gull is not eliminated yet.
>Dick Newell, Cambridge, UK

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


[ << | >> | ^^ ]

Subject: Re: Fw: Great Gull
From: Peter Adriaens <peter.adriaens(AT)DUTCHBIRDING.NL>
Date: 4 Apr 2003 8:27am

A 2nd winter Great Black-backed Gull with rather greyish tibia, and pink tarsus
with
dark bars to the front can be seen at
http://www.birdsnaps.com/gbbg/gbbg2cy/gbbg2cy11.htm
On my monitor, I cannot see a greenish tinge on the tibia of gull A, but in any
case,
this has been recorded in adult birds at least. Just for your entertainment,
here is a
2nd winter GBBGull with one pink and one yellow-orange leg:
http://www.birdsnaps.com/gbbg/gbbg3cy/gbbg3cy02.htm

This is also my last post on this bird, as I think the main question "Is gull A
a typical
Kelp Gull?" has been answered.
People are now getting more into the debate "Could gull A possibly be a (not so
typical) Kelp Gull?" This is a much more speculative question. Any answer to it
is
less interesting than the answer to the main question.

Bye for now,
Peter


[ << | >> | ^^ ]

Subject: Re: Fw: Great Gull
From: Martin Reid <upupa(AT)AIRMAIL.NET>
Date: 5 Apr 2003 7:22am

Dear all,
I feel Peter and Bert-Jan are wise to suggest an end to this discussion - I
agree that based upon these two photos, we are have a bird that is
unidentifiable, and we are left to argue semantics with no way to prove
anything.
I will close by thanking Peter for the two URLS of GBBGs - that 2nd one
with the different legs recalls an adult smith HERG I photo'd with a
similar condition:
http://www.martinreid.com/hsmitp56.html
However regarding the Peter's first bird: on my monitor there is almost no
similarity between the tibia color of Peter's and Norman's birds: on the
latter I see the tibia as wholly gray with a tinge of olive-green -
especially at the lower end; on Peter's bird I see at best a hint of gray
tone in an otherwise washed-out flesh tone.  I agree that the dark barring
on the front of the tarsi is similar enough.
As to Peter's remark:  'I think the main question "Is gull A a typical Kelp
Gull?" has been answered'  - I'd like to ask: typical for WHICH
populations?  Norman's bird certainly appears to be atypical (on molt) of
the easily-studied and known populations from the higher latitudes, but
what about any breeding colonies at lower latitudes; maybe it IS typical of
those populations?
I could reject every single LBBG from North America on the grounds that
their molt is not typical of the birds in the UK - but there are other
populations - ones that did not exist 50 years ago - for which they are
typical... maybe a similar situation exists for Kelp? Just a thought.
Cheers,
Martin

At 4/4/2003 08:27 AM -0700, you wrote:
>A 2nd winter Great Black-backed Gull with rather greyish tibia, and pink
>tarsus with
>dark bars to the front can be seen at
>http://www.birdsnaps.com/gbbg/gbbg2cy/gbbg2cy11.htm
>On my monitor, I cannot see a greenish tinge on the tibia of gull A, but
>in any case,
>this has been recorded in adult birds at least. Just for your
>entertainment, here is a
>2nd winter GBBGull with one pink and one yellow-orange leg:
>http://www.birdsnaps.com/gbbg/gbbg3cy/gbbg3cy02.htm
>
>This is also my last post on this bird, as I think the main question "Is
>gull A a typical
>Kelp Gull?" has been answered.
>People are now getting more into the debate "Could gull A possibly be a
>(not so
>typical) Kelp Gull?" This is a much more speculative question. Any answer
>to it is
>less interesting than the answer to the main question.
>
>Bye for now,
>Peter

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


[ << | >> | ^^ ]

Subject: Re: Fw: Great Gull
From: "Norman D.van Swelm" <Norman.vanswelm(AT)WXS.NL>
Date: 5 Apr 2003 11:24am

Peter Adriaens wrote: > a good example of a late autumn 2cy Great
Black-backed Gull with obviously
> ongoing moult in the wing-coverts can be seen on Mars Muusse's website:
> http://www.birdsnaps.com/gbbg/gbbg2cy/gbbg2cy20.htm
> This bird was ringed as a pullus in Denmark. The photo was taken on 22
> October, so I am not sure if the "law" you proclaim that "all immature
> Great Black-backed Gulls have finished moulting these feathers LONG before
> November", holds true for this Danish bird at least.<

My feeling is that you did not understand my message. According to Ginn &
Melville,1983 (Moult in Birds, BTO Guide 19) adult Great Black-backed Gulls'
complete post-nuptial moult begins late May and finishes early December. The
same source says:"Immatures start complete moult up to 2 months ahead of
adults." Hence immatures' complete moult ends early October and this is
in line with our own findings. It is obvious that "gull a"
http://www.martinreid.com/gullsp32.html  does not fit in this picture. It is
neither in a northern hemisphere 1st winter nor in a dito 2nd winter
plumage. This, the thick-sett bill and the dark row of greater coverts is
what drew my attention in the first place.
So did the freshest mantle feathers. They are black with gingery edges. In
any of the European dark-mantled species these feathers are completely dark
grey or black when released. None of these species too have a dark band
formed by the greater coverts in immature plumages as shown in "gull a " see
or indeed in the birds shown in the Birding World article! As I said before,
I consider this as diagnostic for Kelp Gull and I consider it of crucial
importance when identifying immature Kelp Gulls among immature European
gulls.

It is an excellent idea to refer to http://www.birdsnaps.com since here you
can find many examples sustaining my findings. Besides, for those of you who
are not familiar with Great Black-backed Gulls it presents a nice set of
instructive pictures as well.

Dick Newell wrote:> However, arguments about moult timing should acknowledge
that Kelp Gulls
> (vetula?) breed in the Northern Hemisphere in Senegal and Mauretania (I
> don't know when). <

a few pairs are known to breed in Senegal and a fascinating mixed pair of
Yellow-legged Gull (atlantis) x Kelp Gull has at least nested once on the
Banc d'Arguin in Mauretania.
.
Dick Wrote:>> I must say that, although there are some similarities with the
bird
referred to in Plate 13 (BW Vol 14 No 3 page 117), there are at least as
many
> differences.<

What struck me here is that "gull a" and the bird in Plate 13 not only share
completely identical tertial patterns but "jizz" and tail pattern as well
and the latter is alien to European gulls as well.

Dick wrote:> One of the commonest hybrids in Holland must be graellsii x
michahellis -
> some things tempt me towards this e.g. size, eye-shadow, stout bill, but I
> cannot really make it fit.<

Quite a few fuscus x atlantis cq. michahellis but also argentatus x
michahellis are born each year and we have some idea as to what they look
like partly because we colour-ringed some of them. They too moult like their
respective parents and thus unlike "gull a", they too do not show a dark
band of greater coverts as "gull a" has and I have never seen one with a
bill or tail such as "gull a" has.

Alvaro Jaramillo wrote> Just for the record, in my opinion Bird A looks
>nothing like a South American or Antarctic Kelp Gull. I realize that you
folks are thinking of
> the African form, but one could develop a pretty clear argument against a
> South American Kelp Gull for this bird.<

I for one would be very interested to read your clear argument and also how
you distinguish immature Kelp Gulls from dark immatures of
American gull species.
Norman