Re: Vagrant Gull = Eastern Siberian Gull

To: Jon King <>, Birding-Aus <>
Subject: Re: Vagrant Gull = Eastern Siberian Gull
From: Mick Roderick <>
Date: Mon, 18 Feb 2008 18:01:54 -0800 (PST)
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: [Birding-Aus] 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
and should be adhered to. However, based on extensive experience with
all these taxa in the field and museums, and discussions with many
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
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
so Occam's Razor cuts quite cleanly for the Cooktown bird being

Finally, vegae does not winter routinely in south-east China. This is
an oft-repeated misunderstanding based on older literature. Geoff
and I spent several months (over the course of half-a-dozen winters)
surveying gulls throughout Japan, Korea, and  China south to Hong
The furthest south (and west) that we had pure vegae was near Shanghai
(only two individuals), and there they were already greatly
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
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
vegae is in Japan and (mainly eastern) Korea, that of mongolicus is
coastal and interior China, north and east to (mainly western) Korea
southernmost Japan. The status of large gulls in the islands of
South-East Asia is poorly known, and the few earlier records are
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
as all these taxa have long migration routes and tend to wander

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
> 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
another one you and I have never heard of. You may though have heard

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!
isn't it? Being a birder is hard enough without their activities
our problems.
    My wife and I have just arrived home from braving the floods (we
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
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
to use the slightly more modern Monroe & Sibley's (1993), A World
then the bird is simply the good old Herring Gull, Larus argentatus,
the sub-species 'vegae' called Vega Gull. It doesn't look anything
European version though. If we follow or adopt a more modern
as Clements 6th edition (2007), then the bird is split off as the
Siberian Gull, Larus vegae, which has two subspecies, this being
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
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;
pattern seems to better fit the nominate vegae! Both winter in SE
    And yes Laurie, BARC frequently consults overseas experts.

Mike Carter
30 Canadian Bay Road
Mount Eliza  VIC 3930
Tel  (03) 9787 7136


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