Great Black-backed Gull (Larus marinus) 2cy: June 14 2002, Le Portel - Boulogne sur Mer, France (50.42 N - 01.34 E).
An individual with very contrastingly patterned fresh median coverts. This bird is moulting the rectrices.
The upper three tertials are second generation. The lower tertails are missing. The greater coverts #1-3 are old second generation feathers, included in the post-juvenile moult, #4-5 are fresh second generation and very dark and densely patterned, #6-7 were moulted in the post-juvenile moult and the outer greaters are fresh again. All medians and lower lesser coverts were replaced, but the outermost lower lessers still have to grow a few inches. The juvenile lesser coverts have been shed and second generation feathers are growing in. Five lower upper scapulars have been replaced for third generation.
The soft parts are very immature with the bill mostly black.