Mick,
First I want to let everyone know: I am NOT saying that the Cooktown bird is a
hybrid.
To answer Mick's questions:
1. Possible?
Yes, it is possible that the bird is a hybrid. (hybridisation between the large
Larus taxa has not only been well-documented in Europe but also in North
America, I am not sure about Asia).
2. Likely?
I don't know how likely it would be.
Of course there is a lot published about hybridisation. However, observers
often tend to call a bird a 'hybrid' only because it is difficult to ID (this
happens especially with the ID of large Larus which are very variable). On the
other hand, it is extremely difficult to rule out a hybrid.
So, I am sorry: No clear answer to your question!
Nikolas
----------------
Nikolas Haass
Sydney, NSW
----- Original Message ----
From: Mick Roderick <>
To: Jon King <>; Birding-Aus <>
Sent: Tuesday, February 19, 2008 1:01:54 PM
Subject: Re: Vagrant Gull = Eastern Siberian Gull
Just thinking out aloud...
The identification of this bird seems to be puzzling everybody. My question is,
can this bird be positively identified from plumage alone, especially given the
known hybridisation of Gulls, including the 'Herring-type Gulls' (which appears
to be well-documented in Europe)??
It seems to be showing features of several taxa, so could we be looking at the
result of a hybridisation event and if so, can this be solved by simply looking
at it and/or fotographing it?
Jon, Nikolas...your thoughts?
Mick Roderick
----- Original Message ----
From: Jon King <>
To: Birding-Aus <>
Sent: Tuesday, 19 February, 2008 11:34:44 AM
Subject: Re: Vagrant Gull = Eastern Siberian Gull
Having finally returned home from business travel, I have had a chance
to start sifting through my many images of gulls from East Asia, and
look in more detail at images of the Cooktown bird. I think I might take
a bite of humble pie and climb back on the fence, as some of the
features of this bird do indeed suggest my initial thought, vegae ("Vega
Gull" in the strict sense), rather than mongolicus ("Mongolian Gull").
If one is to follow the taxonomic approach that these are the same
species then perhaps we're dealing too much in semantics, but given the
direction of global gull taxonomy, the identity should be narrowed down
as tightly as possible in anticipation of future splits.
In particular, in the flight shots the greater coverts appear to show
extensive unmarked brownish bases which is not a good feature for
mongolicus (but typical for vegae). On the perched bird images, it looks
like these these coverts have faded to an off-white, but then on the
excellent open wing shots, it looks like the bases (which wouldn't fade
much) are fairly brown.
My recollection of the variation in the tail patterns of the two taxa
was imperfect, and consulting a lot of photos, the Cooktown bird does
have a pattern more suggestive of vegae than of mongolicus, as Mike
Carter indicated. I still think the Cooktown bird's pattern falls within
the range we have seen on mongolicus, but it is unfortunate that it
appears to be at the vegae end of that range rather than more firmly in
the middle, and right now I can't find a good comparative photo to
support that possibility.
Hopefully I will have more time in the next few days to sit down and
digest this problem more fully.
Thanks for your patience, Jon.
>>> "Jon King" <> 2/18/2008 12:06 PM >>>
Mike et al.,
Just a few quick comments/clarifications. Among the Palearctic gulling
community, mongolicus is now generally placed with the Caspian Gull
group (as Larus [cachinnans] mongolicus). The cachinnans group was
itself once part of the Yellow-legged Gull group (michahellis), which
was of course once itself part of the all-encompassing "herring gull"
(argentatus) group back in the 1980s! See Grant, Peter. 1982. Gulls: a
guide to identification - with a second edition in 1986.
The most useful mainstream reference for both this latest taxonomic
position and for basic ID material on the taxon mongolicus is:
Olsen, K. M., and Larsson, H. 2004. Gulls of Europe, Asia, and North
America. Helm.
In the interests of full disclosure, I was a minor consultant in the
production of that book, and while far from perfect and now already
somewhat dated, it remains a useful resource when dealing with many of
these taxa. Of course, if BARC's policy is to use Sibley and Monroe as
the Checklist for species new to Australia then that is a consistent
one
and should be adhered to. However, based on extensive experience with
all these taxa in the field and museums, and discussions with many
other
gull folks, it is very likely incorrect (both phenotypically and
genetically) to place mongolicus with vegae.
Regarding tail patterns, the pattern of the Cooktown bird actually
fits
mongolicus as well as that of vegae, although both taxa show some
variation. Published photos of these taxa tend to show classic tail
patterns, rather than the full range of variability of course.
Fortunately, as discussed in my earlier message, many other characters
are excellent or even classic for mongolicus but are not shown by
vegae,
so Occam's Razor cuts quite cleanly for the Cooktown bird being
mongolicus.
Finally, vegae does not winter routinely in south-east China. This is
an oft-repeated misunderstanding based on older literature. Geoff
Carey
and I spent several months (over the course of half-a-dozen winters)
surveying gulls throughout Japan, Korea, and China south to Hong
Kong.
The furthest south (and west) that we had pure vegae was near Shanghai
(only two individuals), and there they were already greatly
outnumbered
by mongolicus. I subsequently had a likely vegae (first year) in Hong
Kong in 2000, but it is a vagrant there, or perhaps a rare winter
visitor at best. This new awareness of the situation with large gulls
in
Hong Kong is summarised in Carey, G. J. et al. 2001. The Avifauna of
Hong Kong. Hong Kong Birdwatching Society.
>From an east/south-east Asian perspective, the core wintering range
of
vegae is in Japan and (mainly eastern) Korea, that of mongolicus is
coastal and interior China, north and east to (mainly western) Korea
and
southernmost Japan. The status of large gulls in the islands of
South-East Asia is poorly known, and the few earlier records are
usually
just "herring gulls" or may be misidentified in some cases. Based on
known modern distributions, mongolicus and taimyrensis are most likely
in Indonesia. Distribution is of little help with a vagrant gull
anyway,
as all these taxa have long migration routes and tend to wander
widely.
Apologies for yet another lengthy message on this arcane topic! I hope
to pull together some relevant photos shortly.
Cheers, Jon.
Jon King
Senior Ornithologist
EDAW, Inc.
(+1) (916) 414 5854 office
(+1) (916) 952 7345 mobile
>>> "Mike Carter" <> 2/18/2008 4:36 AM >>>
Bob Inglis asked
> Could someone please tell me which species (or sub-species) is being
> considered as the likely identity of the 'unusual' gull presently
being
> stalked at Cooktown?
Nikolas Haass tried to answer your question Bob but not very simply,
confusing all of us even more by introducing Baraba Gull into the
debate,
another one you and I have never heard of. You may though have heard
of
Steppe Gull another name for it. Mind you, until this gull appeared in
Cooktown, I hadn't!
The problem is Bob, there are some seriously misguided souls around
(one I
know has the initials TT and is a Queenslander like you) that laud and
admire splitters, when you and I know they should be condemned!
Pathetic
isn't it? Being a birder is hard enough without their activities
adding
to
our problems.
My wife and I have just arrived home from braving the floods (we
drove
through water rushing across one bridge), and like numerous others I
photographed the gull from all angles. Consequently I'm too eager for
bed to
deal thoroughly with this now but I am keen to know what to call this
new
tick. So briefly, this is how I see it.
To date, it has been BARC's policy to use Sibley and Monroe as the
Checklist for species new to Australia. Don't have that handy but if
we
were
to use the slightly more modern Monroe & Sibley's (1993), A World
Checklist,
then the bird is simply the good old Herring Gull, Larus argentatus,
albeit
the sub-species 'vegae' called Vega Gull. It doesn't look anything
like
the
European version though. If we follow or adopt a more modern
checklist,
such
as Clements 6th edition (2007), then the bird is split off as the
Eastern
Siberian Gull, Larus vegae, which has two subspecies, this being
probably
the race mongolicus. The misguided among us consider this taxa a full
species and call it a Mongolian Gull. The photo of a first winter bird
of
this taxa in Shimba's (2007) Photographic Guide to the Birds of Japan
is a
dead ringer for the Cooktown individual. There is just one problem;
the
tail
pattern seems to better fit the nominate vegae! Both winter in SE
China.
And yes Laurie, BARC frequently consults overseas experts.
Mike Carter
30 Canadian Bay Road
Mount Eliza VIC 3930
Tel (03) 9787 7136
===============================
www.birding-aus.org
birding-aus.blogspot.com
To unsubscribe from this mailing list,
send the message:
unsubscribe
(in the body of the message, with no Subject line)
to:
===============================
===============================
www.birding-aus.org
birding-aus.blogspot.com
To unsubscribe from this mailing list,
send the message:
unsubscribe
(in the body of the message, with no Subject line)
to:
===============================
===============================
www.birding-aus.org
birding-aus.blogspot.com
To unsubscribe from this mailing list,
send the message:
unsubscribe
(in the body of the message, with no Subject line)
to:
===============================
Get the name you always wanted with the new y7mail email address.
www.yahoo7.com.au/y7mail
==============================www.birding-aus.org
birding-aus.blogspot.com
To unsubscribe from this mailing list,
send the message:
unsubscribe
(in the body of the message, with no Subject line)
to:
==============================
____________________________________________________________________________________
Be a better friend, newshound, and
know-it-all with Yahoo! Mobile. Try it now.
http://mobile.yahoo.com/;_ylt=Ahu06i62sR8HDtDypao8Wcj9tAcJ
===============================
www.birding-aus.org
birding-aus.blogspot.com
To unsubscribe from this mailing list,
send the message:
unsubscribe
(in the body of the message, with no Subject line)
to:
===============================
|
