Sp, Gull seen on 15.4.14 - WHAT IS THAT ?

[amir ben dov]

bird seen on 15.4.14
its extremely interesting

1. active moult in outer primaries by mid April.
this bird is still groing its P9 (90%) and P10 (60%), this must mean thats its a high tundra bird
as all other gulls we know from Israel have finnished their moult ages ago
even north eastern Heuglini finnished in Mid December - 2nd week of January

2. i also find it hard to understand the aging
it looks as very retarted 4th CY or super advanced 3rd

3. back colors are also very strange
quating Mars: "medium grey upperparts, too dark for classic ponticus Caspian Gull, and too pale for classic heuglini and fuscus"

4 Gull massively marked on the nape and hind neck unlike any heuglini or bara seen in Israel
or known to me from litrature

5. as P9 is almost fully grown (90%), it shows that the wing is quite short and has short exposure from the tail tip

6. to me the fitures looks as:
Bill massive long and straight
Eye is a 3rd CY one
Head shape looks very "Yellow Legged / Herring" style
size is a male size but depends ofcourse on Sp,

anyway - any chance to get your ideas

[Theo Muusse]

Hi Amir,
the full winter plumage on this date, combined with the active moult should suggest a high arctic bird.
The cachinnans like head with long legs and darkish mantle suggest the former "pale big heuglini/ taimirensis form.
The large amount of neck-streaking is obvious.
The non-angle bill is obvious.
The dark secondaries certainly look like 2nd generation, suggesting a rapid 2nd winter bird.
This seems confirmed by bill-colour and neckstreaking.

Theo

[amir ben dov]

Thanks alot Theo
if taimirensis it will be the first for Israel
Vega was never recorded here but even 50% Vega is good for us
can you ask more people to give their opinions ?

thanks
Amir

[JanJ]

Hello Amir!

Thanks for great pic and let me say at once, although difficult one this - regarding ageing and exact species/sp. I don´t think we have to go mongolicus or vegae, there´s to many features wrong for these, like billshape and moult score as well as primary pattern.
Regarding age - with susch an adult like primary pattern, one should at least consider a 4 cy type. The not fully grown p10 and also p9 (a bit late at this time of year), as you say, would suggest a northern ssp and that´s where my thoughts is landing, namely heuglini (or maybe a late moulting barabensis fot that matter?) From above the black on p8 doesn´t reach the primary coverts as usual in heuglini, with some exeptions of course but we don´t see the end of the black on p10 from below - diagonal shape or concave, the first would supports heuglini. However, the grey tone seems a bit to pale for heuglini. So what exactly can it be? There are some Caspian structure, bill shape and long legs with thin tibia to it but the impression and pattern doesn´t strike you as one. If I had to - I´d say heuglini type Amir but that might be wrong of course.
Why not put it on the ORG (Gull Research Organisasion), forum (!), Amir. I think that Mars and Peter would have some saying.

Thanks again and looking forward to some comment on this gull

All the best

Jan

[adriaens]

Hi,
to me, this looks like one of those "not really barabensis" types that seem to be present in the Middle East in small but significant numbers.
It is probably best to leave such birds unidentified.
Sorry to not be able to say more...

[marsmuusse]

I'll just copy an earlier reply I've sent to Amir by mail:
-------
No, I've not really a good idea Amir. Intense head streaking (or better: neck streaking) by April may indicate a bird not from the steppe, but from the tundra. By April most steppe birds are white headed.

Great that you managed to take more pictures, and all the aspects of this bird are really well documented. A few things that strike are:
- medium grey upperparts, too dark for classic ponticus Caspian Gull, and too pale for classic heuglini and fuscus.
- 3rd generation flight feathers (except S13-S16, normally the last block of secondaries to be replaced in an ordinary moult sequence), which show sub-terminal black on P10-P1.
- active moult in outer primaries by mid April.
- cachinnans jizz with long slender bill, and bird on long looking legs,

These features cumulate into an odd bird (to me at least). We know of primary moult in sub-adult birds of taxa like Lesser Black-backed Gull, and I'm not aware of documented birds like this from argentatus, michahellis or cachinnans stock. For cachinnans the moult scheme would be aberrant and the upperparts are too dark, but just on how the birds looks, cachinnans would be a good option (and maybe barabensis?).
However, and that may sound as an easy escape rout, sorry, I would not rule out the option of Greg Region origin; birds from what seem to be mixed colonies in reed marshes and birch forest lakes east of Moscow. (see also: http://gull-research.org/heuglini/05cydec.html ).