www.gull-research.org

I already posted this bird on the waarneming.nl-forum, but apparently there was no one present with a satisfying answer. I'll have a re-try here. Some two weeks ago I saw this 2CY Gull in Groningen, Netherlands, and it confused me a little. My first thought was a michahellis, but both the pattern on the scapulars as the inner primaries, as well as the general impression also remind me of Greater Black-backed, albeit a very small one.
Two weeks before, on the exact same location, I saw this one: http://waarneming.nl/waarneming/view/69816338 I.m.h.o. it very much looks like the same bird, which I identified as GBBG. However, a week later, Lazar Brinkhuizen saw this bird: http://waarneming.nl/waarneming/view/70051251?_popup=1, which he named michahellis; again it looks like the same bird to me.
Two questions: are all these birds indeed the same individual, and most importantly: what is it?

hello martijm,

to my eyes it is the same bird indeed (in all 3 photosessions) and i'd call it a michahellis. i don't see anything wrong with scap and inner primary pattern.

lou

The new tail feathers - with extensive, solid black tail band - leave little doubt that this is a michahellis indeed.

Thanks, the tail is something I should have noticed; it doesn't fit GBBG at all. In other aspects, this is for me an instructive bird that broadens my views on 2cy Micha (as did another rather slowly moulting 2cy I found in Groningen recently, check www.pbase.com/martijnbot/recent for pics).