Brett..last year (Winter), I observed an adult fuscus type gull (looking slightly smaller, less robust than accompanying LBBG and with amazing primary extensions (presumably a female owing to the exaggerated wings), standing on a concrete apron adjacent to the Thames (Inner London), with Lesser Black-backed Gulls and other assorted gulls Herring, Common, and Black headed one side, with an adult Grtr.Black Backed Gull perhaps 2 metres away, on the other side. Apart from having the ''luxury'' of comparison gulls...the black mantle/scaps and wings of the bird ''mirroring'' the ''black'' of GBBG (no mirrors visible on the primaries) the most obvious structural difference apart from smaller size, was the primary length!...I thought at the time the name ''Pheasant Gull'' would have been more appropriate than Baltic Gull. Having never seen a gull from a structural perspective, looking anything like this. I unwittingly dismissed it as a fuscus (am not really a Laraphile), and to compound it..I did not have my customary camera around my neck. It was only some time after, that I realised the relevance of fuscus, within the context of a UK occurence....In short, In my opinion (for what it's worth) this bird looks like a 2nd calendar year fuscus and possibly a female?
cheers