birding-aus

Lesser Black-backed Gull at Broome tip

To: "'Dimitris Bertzeletos'" <>, "'Birding Australia'" <>
Subject: Lesser Black-backed Gull at Broome tip
From: "Jeff Davies" <>
Date: Wed, 23 Jan 2013 13:12:19 +1100
A good move Dimitris and many thanks for the input you have already
coordinated from Finland, it has been very valuable input for all of us to
take on board with this difficult bird. I will be very keen to see what
others on birdforum have to say. Especially keen to hear from anyone with
experience or photos of ssp melisandrae.

Cheers Jeff.



 

-----Original Message-----
From: 
 On Behalf Of Dimitris
Bertzeletos
Sent: Wednesday, 23 January 2013 12:49 PM
To: Birding Australia
Subject: Lesser Black-backed Gull at Broome tip


Hello all again,

Just for completeness sake, wouldn't it be prudent to ensure that this bird
isn't a Kelp Gull? Whatever it is it is certainly on the male bulky side of
intermedius and fuscus if it is one.

I have posted a link to the images of the birds on birdforum.net which
several larophiles visit frequently. This is the tread:
http://www.birdforum.net/showthread.php?p=2644996#post2644996

All the best,

D.

> From: 
> To: ; 
> Date: Wed, 23 Jan 2013 01:19:57 +1100
> CC: ; ; 
> ; ; 
> ; 
> Subject: Re: [Birding-Aus] Lesser Black-backed Gull at Broome tip
> 
> 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: Re: [Birding-Aus] 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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