Visa states " All in all, this individual seems to have so many "minor
faults" that I would like to familiarize myself with the arguments that
state this cannot be a dominicanus."
I would suggest the bill is way too narrow for a kelp Gull, also the white
trailing edge is equally too narrow especially at the inner primaries, and
the degree of primaries extending beyond the tail tip compared to length of
tail beyond tertials is too long allowing for this bird having lost its
longest tertial. Olsen describes ssp melisandrae of Kelp Gull from
Madagascar as having a smaller and slimmer bill than Cape Gull, but this
Broome bird's bill would represent an extremely slimmer Kelp Gull indeed.
However I admit to not having ever seen an image of melisandrae, can't find
one anywhere.
Cheers Jeff.
-----Original Message-----
From:
On Behalf Of Harry Nyström
Sent: Wednesday, 23 January 2013 12:29 AM
To: Nikolas Haass
Cc: Jim Allen; Danny Rogers; ; George Swann of
Kimberley Birdwatching; Tony Palliser; Rohan Clarke
Subject: Lesser Black-backed Gull at Broome tip
Hello,
Here are the first comments from Finland after my rough translation. The
comments are provided by Mr. Visa Rauste, who has studied gulls for several
years (decades?) and has been on the national rarities committee for almost
20 years of which 11 as the chairman (until 2011, when he left the seat).
Another person is also quoted, and the person is clearly stated. I will
still try to forward the photos to some other laridists for further review,
but to my knowledge the comments by Mr. Rauste are practically as competent
as can be.
I'll keep you posted if other comments emerge.
Visa's comments:
*"First of all, the identification is very dependent on the accuracy of the
white balance and correctness of the exposure of the images. If we go with
the assumption that they are correct, the bird is definitely not a "normal
heuglini". The upperparts of a heuglini should never be that dark and they
should show a clearer bluish tinge. On the other hand, it should be noted
that the line between a heuglini and a fuscus is not as clear as sometimes
is suggested. And because of that, there has not been much support in Europe
and especially in Finland to draw a line between these two taxons to split
them into two different species.
*
*When it comes to the structure of the bird, it is to my opinion fuscus
enough, but the structural difference between a fuscus and a heuglini is so
small and more or less on the average that I wouldn't give it much weight
when identifying an individual as a distant rarity on the other side of the
globe.
*
*The moult is also better in line with fuscus, although I don't have my own
data collected of wintering birds. The interruption of the moult in the
primaries at this time of the year in that way is not typical for either
taxons but is the "personal solution" of the individual that is probably
related to the otherwise extraordinary life phases of the bird.
*
*A little disturbing feature comes to my mind regarding the photos: the iris
of the bird is untypically dark for a fuscus, which almost always
(especially during Summer) has a clear light yeallow iris. The iris should
not show any or only slight spotting, when this individual shows it quite a
lot: http://www.pbase.com/wildlifeimages/image/148413423
*
*
*
*I also have to say that I don't know anything about the gulls of the
southern hemisphere, but I have to rely that the locals can identify and
exclude them."*
------
Visa's comments after having a good night's sleep in between when asked
about the possibility of an intermedius:
*"Yesterday I wasn't keen on trying to open the whole Lesser Black-backed
Gull -dilemma, and I'm still not. But I'll open it just a little, anyway.
The difference between an intermedius and a fuscus is a "line drawn in
water" when examined on an individual level, although they are different
enough as populations to deserve their subspecies status.
In other words, a "dark intermedius" is identical to a "light fuscus". And I
literally mean "IS identical", not "looks identical". ;-)
*
*Of course, an individual that is lighter than a typical fuscus and darker
than a graellsii (or heuglini) can be called an intermedius. Note that such
a bird might still be from the phasing region of fuscus and heuglini and not
from the phasing region of fuscus and graellsii, which would be the
"genuine" intermedius. Of course, even in Finland we have all kinds of
LBBGs, for example like this - what would you call this:
http://www.helsinki.fi/~rauste/gulls/hannu34.html
*
*Having said that, I still got the feeling yesterday that the individual is
more "dark as a fuscus" than "dark as a typical intermedius". This concerns
of course only the impression on the darkness (which is affected by many
things, starting from the display one uses when viewing the photos). The
darkness cannot be estimated accurately enough from photos, not even as good
as these. If the bird was captured, one could use the Kodak-scale to assess
the darkness of it; a typical graellsii is about 9-11, intermedius
11-13 and fuscus 13-17.
*
*But now all I can give is a "no can do", in addition to throwing out some
impressions. Nevertheless: I have no reason to think this individual is a
heuglini. No reason at all.
*
*But... Something still doesn't add up.
*
*The bird e.g. looks a bit long-legged, but it may not be essential.
*
*What could be essential is the pattern of the innermost primaries: if I am
calculating the primaries correctly (differentiating the outermost secondary
and the innermost primary is not as straightforward as one would think),
this bird has black patterns only in the 6 outermost primaries (P4 might
have a very small dot on the edge of the outer web, but can be seen only in
some very close photos).
*
*Finnish birders, Antero Lindholm and Annika Forsten, have studied the wing
tip patterns on Baltic Gulls (LBBG fuscus) of a known age, and in a data
consisting of 138 +3cy individuals only 1 (one) bird had black in just the
6 outermost primaries: http://www.caluta.liitin.net/Caluta/Caluta1_l.pdf
*
*All in all, this individual seems to have so many "minor faults" that I
would like to familiarize myself with the arguments that state this cannot
be a dominicanus. Unfortunately I won't have the time to do this in the next
few days."*
-------
Some other comments have also been given, this one from Petri Lampila, also
a member of the national rarities committee:
*
*
*"In addition to the minor faults already stated, the individual seems to
lack all winter plumage features (streaking on the head). One would expect
such winter plumage features from a northern hemisphere gull. I don't have
experience from the fuscus in winter plumage, but for example the heuglinis,
which I just recently saw in Goa (ca. 50 individuals), were all very clearly
in their winter plumage. Of course there are exceptions to the rule, but the
list of untypical features is starting to be a little long for a
vagrant."*
Additionally, the possibility of a hybrid should be taken into consideration
somehow - at least according to some.
Cheers,
-Harry
2013/1/22 Nikolas Haass <>
> Hi Mike,
>
> No, this is not an incredible way to argue because it wasn't intended
> to be an experiment using the Broome gull as a 'control'. I was just
> wondering if the NW India birds, in turn, can be used as a valid
> 'control' for the Broome bird. There has been a long discussion about
> these birds in India and apparently it still has not been resolved
> which taxa winter in NW India. So, yes, the Indian birds could be heuglini
OR taimyrensis.
>
> To the Broome bird: It still doesn't look like a perfect L. f. fuscus
> to me for the reasons I discussed in previous mails. I know that some
> people favour L. f. fuscus, but to my knowledge a number of people
> besides me have made the case for L. f./h. heuglini, too. I agree that
> the bird is too dark for taimyrensis, which I suggested based on iris
> colour and bill shape. I am interested in the identification of this
> bird and contributed to it to my best knowledge.
>
> BTW in case the bird will be proven to be a L. f. fuscus, I won't be
> embarrassed at all.
>
> Nikolas
>
> ----------------
> Nikolas Haass
>
> Sydney, NSW
>
>
> ________________________________
> From: Mike Carter <>
> To: Nikolas Haass <>; Tony Palliser
> <>;
> Cc: 'George Swann of Kimberley Birdwatching' <
> >; 'Rohan Clarke' <
> >; 'Danny Rogers' <>;
> 'Tony Palliser' <>; 'Jim Allen'
> <>
> Sent: Tuesday, January 22, 2013 9:59 PM
> Subject: Re: [Birding-Aus] Lesser Black-backed Gull at Broome tip
>
>
>
> Nikolas, what an incredible way to argue? It seems that you are saying
> that because you say that the Broome bird is heuglini that is what it
> is and any evidence leading to a contrary conclusion must be false.
> Surely the logical conclusion is that the Indian birds are paler than
> the Broome bird because they are heuglini as would be expected at that
> site whereas the Broome bird is fuscus as the colour and other factors
> suggest.
>
> Mike Carter
> 30 Canadian Bay Road
> Mount Eliza VIC
> 3930
> Tel (03) 9787 7136
>
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