(3 images) Herring Gull 5.412.512(argenteus), October - November 2003, the Netherlands (52.27, 04.33E).
Probably ringed as pullus in IJmuiden, the Netherlands: ringed Vogeltrekstation Arnhem Holland 5.412.512. As is standard for 1cy argenteus, all the wing-coverts are juvenile. All lower scapulars are still juvenile. Some upper scapular have been moulted to second generation (25%-50%) in November.
The partial autumn moult in argenteus (moult from juvenile plumage into so-called "first winter" plumage) includes the body and head feathers. This moult starts as soon as the nest is abandoned (late June) and continues until January. In general, the head turns paler on throat and forehead. The breast will turn paler as well. The feathers on belly and vent will still be juvenile in most 1cy argenteus by November. From July onwards, the mantle and upper scapulars are moulted to second generation feathers, showing an anchor pattern and a dark base. The lowest row of scapulars are still juvenile by March in most 2cy birds (contra e.g. michahellis). The notched pattern of the juvenile scapulars is repeated on the juvenile lesser, lower lesser and median coverts, although the medians have paler centres. The juvenile greater coverts show a 'piano-key' pattern; on the outer greater coverts as well. The tertials have an obvious notched pale fringe and transversal bar.
The juvenile wing-coverts, rectrices and remiges start to bleach and show wear in the fringes from September onwards. The secondaries, primaries and primary coverts are dark with a small white tip, but the juvenile inner primaries show an obvious pale window, prominent from below and above. The under-wing is rather uniform grey-brown patterned. The tail has a broad sub-terminal band and isolated dark bars on the basal half. The iris is dark, the bill is blackish, sometimes with a paler base, and the legs are flesh-pink.
(top image) 5.412.512 October 25 2003, Amsterdam, the Netherlands. Picture Ruud Altenburg.
(below 2 images) 5.412.512 November 11 2003, IJmuiden, the Netherlands (52.27, 04.33E).
This can hardly be same the bird, note e.g. the pattern on the median coverts and the lower scapular moult score. However, it's hard to find out which reading was incorect.