Mediterranean Gull (L. melanocephalus)
Mediterranean Gull 1cy & 3cy 32E0 August 2008 & August 2010, Le Portel / Boulogne-sur-Mer, NW France. Picture: Jean-Michel Sauvage.
Bird from Belgium. Ringed as pullus: White 32E0 left Bruxelles E911833. Ringed on 06 June 2008 at Noordelijk Insteekdok, Oost-Vlaanderen, BELGIUM (51,17N 4,13E).
below 1cy: 32E0 August 29 2008, Le Portel / Boulogne-sur-Mer, NW France. Picture: Jean-Michel Sauvage.
The partial autumn moult (post-juvenile moult into so-called "first winter" plumage) takes place right from the moment the juveniles leave the colony (usually mid July) and is finished by late September. It's a partial moult of the head and body feathers. The head and under-parts become almost completely white, the head with a clear dark mask of variable size behind the eye extending over the nape. The eye-crescents are white. The second generation mantle and scapulars are plain grey. The edges of the rich brown wing-coverts bleach to pale brown and the white fringes are all but worn away. Only a limited number of lower lesser coverts and median coverts are included in the post-juvenile moult. In this individual the upper tertials and innermost greater coverts have been replaced by plain grey second generation feathers. All juvenile feathers show some wear by October, contrasting with the recently moulted second generation feathers. The base of the bill starts to turn paler and the legs remain dark, but on some birds turn slightly paler.
Note that the comments on moult are based on observations of juveniles from and in Western Europe in early autumn. More easterly fledged Mediterranean Gulls may postpone their moult to first winter until later in the autumn and very fresh looking juveniles may be encountered well into October.
below: 3cy 32E0 August 06 2010, Le Portel / Boulogne-sur-Mer, NW France. Picture: Jean-Michel Sauvage.
From late summer to September, a complete moult takes place, into so-called "third winter" or "adult winter" plumage. The head pattern resembles the pattern in first winter birds, with blackish mask behind the eye. The mantle, scapulars, tertials and all the wing-coverts are replaced for plain pearl-grey feathers. The secondaries are completely white. The adult primaries are shiny pearly-grey, flashing white at a distance. There is a black line along the outer-web of P10 (and sometimes on P9 as well). Secondaries, under-wing and tail all completely white. The bare part coloration in 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.