Mediterranean Gull E52 3cy, August 09 2003, Le Portel /Boulogne-sur-Mer, France (50.42N,1.34E).

Ringed individual: left green E52. Note the pattern of the outermost primaries P8-P10, which are second generation and still to be moulted. The black pattern in the outer primaries is diagnostic for 3cy Mediterranean Gull in summer. From late summer to September, a complete moult takes place, bringing birds into so-called "third winter" plumage. The head pattern in this bird still resembles "summer plumage", but after finishing the complete moult, the pattern will resemble first winter birds, with a blackish mask behind the eye. The mantle, scapulars, tertials and all the wing-coverts will be replaced for plain pearl-grey feathers. 
The secondaries are completely white. In this 3cy Mediterranean Gull, the wing-tip pattern is diagnostic with black on the second generation P7-P10: P7 has a black sub-terminal band, which becomes gradually larger on the outer primaries as the black patch "eats up" along the edge of the outer-web, most prominent on P10, although P10 lacks the sub-terminal band. In some birds, the outer greater primary coverts may show dark markings as well. The new adult-like primaries in 3cy autumn birds are shiny pearly-grey, flashing white at a distance. By October, there will be a black line along the outer-web of P10 (and sometimes on P9 as well). Secondaries, under-wing and tail will be moulted to completely white feathers. The bare part coloration is similar to adult plumage: Iris brown, orbital ring red or orangey-red, the bill red or orangey-red with a black bill-band (and a yellowish tip) and the legs dull reddish or dark.