Great Black-backed Gull (Larus marinus)

(last update: July 12, 2015)

Jean-Michel Sauvage (France)
Morten Helberg (Norway)
Nils Helge Lorentzen (Norway)
Mars Muusse (Netherlands)

Great Black-backed Gull (Larus marinus) 2cy: June 23 2003, IJmuiden, the Netherlands (52.27 N - 04.33 E).

An individual in active wing-covert moult. Many lesser coverts are missing, but some fresh second generation feathers are already visible. All median and lower lesser coverts have been replaced. The gap in the central greater covert row is obvious, exposing the juvenile secondaries underneath. The innermost greater coverts have been replaced, while the adjacent feathers are still juvenile. The complete central part of the row is missing, but from the outer wing,  new greater coverts moult inwards. The upper two tertials are second generation as well, the third is growing and the juvenile lower tertials and innermost secondaries are just visible.

This bird is moulting the rectrices, with the central tail-feathers growing / missing. Primary moult stage: P7-P10 still juvenile, P5 slightly longer than the fully grown P4. Recently moulted upper scapulars have buffish centres and show the same (second generation like) pattern as the white based lower scapulars. The soft parts are very immature with the bill mostly black.