Its one of those thread I normally learn, but the right Gull doesnt have a Great-black-backed Gull-jizz to me:
-wing projection is to long
- what seems to be an extensive all dark tail is not good for GBBG (I get the impression, that this can be judged with confidence?)
-I would expect an immature (1 or 2 cy ) GBBG to show more extensive white frings(barring to wing coverts. So my question is: can an immature GBBG have so heavily worn wing-coverts that this area appears so uniform "washed out dark" like this bird here? Answer is most probably yes.
Conclusion? Real Gull experts, please help. I think, right bird is a Herring Gull, with the caveat, that I am no Gull expert