Italy, probable Heuglin's Gull 2ndS

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italianbirder
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Italy, probable Heuglin's Gull 2ndS

Post by italianbirder » Fri Feb 19, 2010 10:57 am

Four photos of the same bird taken by Marco Basso in Chioggia, NE Italy, on 4th to 25th April 2005
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Image

Image

Image
Menotti Passarella
Italy
http://gabbianigulls.blogspot.com/

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marsmuusse
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Re: Italy, probable Heuglin's Gull 2ndS

Post by marsmuusse » Fri Feb 19, 2010 9:36 pm

Menotti,
it all seems to fit taxon heuglini very well. Unfortunately we know only so little about the variation in these plumages...

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italianbirder
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Re: Italy, probable Heuglin's Gull 2ndS

Post by italianbirder » Sat Feb 20, 2010 10:08 am

Hi Mars, many thanks. However, IMHO, the only form to rule out is Larus fuscus graellsii, of which I have personally a very limited experience, since it is very unusual in NE Italy (we have many more argentatus Herring and Caspian gulls, and a few intermedius).
Menotti Passarella
Italy
http://gabbianigulls.blogspot.com/

Ruud Altenburg
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Re: Italy, probable Heuglin's Gull 2ndS

Post by Ruud Altenburg » Sat Feb 20, 2010 1:49 pm

It would be highly unusual for a 3cy graellsii to have a pronounced mirror on p10 at this age, but then again, probably not entirely impossible...

Ronald Klein
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Re: Italy, probable Heuglin's Gull 2ndS

Post by Ronald Klein » Sat Feb 20, 2010 2:49 pm

In shape and jizz it looks like a graellsii-Type. Heuglini seems more similar to a "dark grey" Caspian Gull.

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JanJ
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Re: Italy, probable Heuglin's Gull 2ndS

Post by JanJ » Sat Feb 20, 2010 4:05 pm

Ar there any significance to the all white unmarked underving together perhaps with advanced (?) inner primary moult for the time of year?

Jan

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marsmuusse
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Re: Italy, probable Heuglin's Gull 2ndS

Post by marsmuusse » Sat Feb 20, 2010 9:11 pm

I think it will be best to leave this bird labelled ‘heuglini’, until we know more about the variation in this taxon. I see graellsii LBBG quite often, but the combination of features presented by this individual are striking. Furthermore, the location favour heuglini over graellsii as well?
But, I don’t agree the underwing is ‘all white unmarked’ as there are obvious markings on the under-wing primary coverts. And I hesitate to call the moult in the inner primaries ‘advanced’. The only slightly odd aspect is that P1 on the right wing seems to have an obvious broader white tip than P2, in all pictures, which just might indicate it is of another generation or moulted later than P2, but I doubt that.
The third picture where the bird raises the wings show a brown hue on the outer-webs of P1-P4 and the step to P5 look logic in colour and pattern. The conditions of the tips of P1-P10 are similar for all feathers in the left wing, without a moult division.
As Ruud mentioned, the mirror on P10 is striking for this plumage; typically a pattern associated with late moult in the winter (say mid-January as seen in winter images of fuscus and heuglini) and the idea is that birds moulting this late, have different hormone-levels which may result in more ‘adult-like’ feathers.
In my local area, IJmuiden – the Netherlands, I see adult Herring Gulls struggling again with their hormones in January, when the sun melts the snow on the first warm day of the year…

The problem / challenge of course is: can we safely rule out a 4cy bird? Would the outer secondaries eliminate this option?

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JanJ
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Re: Italy, probable Heuglin's Gull 2ndS

Post by JanJ » Sat Feb 20, 2010 9:34 pm

Thanks for the thought on this gull Mars.
Of course not all unmarked underwing as I mentioned, thinking more of the rest of the coverts.
Still it´s amazing how Hannu identifies heuglini (most age groups) on his stunningly good site, when most others prefer not to :o

Jan

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Hans Larsson
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Re: Italy, probable Heuglin's Gull 2ndS

Post by Hans Larsson » Sat Feb 20, 2010 11:43 pm

While it´s more than difficult to be certain on single individuals, one can be quite confident when analyzing the material that Hannu (and other Finns) has collected over the years. The odd western LBBG and maybe some fuscus may have sneaked in, but on the whole I wouldn´t hesitate to call these birds heuglini. Central and northern Finland are probably "safe" grounds, at least up til now, knowing graellsii is becoming more and more regular in the southern Baltic Sea...:-/

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JanJ
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Re: Italy, probable Heuglin's Gull 2ndS

Post by JanJ » Sun Feb 21, 2010 1:51 pm

Hans Larsson wrote:While it´s more than difficult to be certain on single individuals, one can be quite confident when analyzing the material that Hannu (and other Finns) has collected over the years. The odd western LBBG and maybe some fuscus may have sneaked in, but on the whole I wouldn´t hesitate to call these birds heuglini. Central and northern Finland are probably "safe" grounds, at least up til now, knowing graellsii is becoming more and more regular in the southern Baltic Sea...:-/
Perhaps it should be noted that I by no means was questining Hannus (and other people there) identification of heuglini at the different sites involved. I wouldn´t be one of the best candidates for that! I - as Hans also think that their material holds good ground on the whole. I´m just curious, when it comes to certain individuals, what criterias the go by, especially in 3cy to adult like individuals, thats all.

Jan

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