Herring Gull 3cy (argenteus), December 23 2010, IJmuiden, the Netherlands.

Pale grey local bird (probably, not ringed). Mirror on P10, and central primaries typical blackish with well-defined white tips (indication for 3rd gen primaries, instead of 2nd gen). Average plumage for 3cy in this bird, with grey saddle and quite a lot wing-coverts adult-like grey. Strong clues for age often to be found in secondary pattern, which are grey based without large brown centres and without much vermiculation (just visible); and the inner primaries which are adult-like grey with a broad white tip. Primary pattern on P7-P9 (faint tips) probably rules out option of 4cy in December.