(2 images) Herring Gull JX0S 2cy (argentatus), February 28 2004, IJmuiden, the Netherlands (52.27N-04.33E). 

Norway ringed Herring Gull in 2cy. This is a strong powerful 2cy argentatus with most scapulars replaced for second generation feathers. The lowest row of lower scapulars are still juvenile.

The partial autumn moult in argentatus (moult from juvenile plumage into so-called "first winter" plumage) includes the body and head feathers. This moult may start in some birds as soon as the nest is abandoned (late June in argenteus) and continues until January. In general, the head turns paler on throat and forehead, compared to the juvenile plumage. The second generation feathers on the breast are paler as well. The feathers on the vent and the under-tail coverts are still juvenile in most 2cy argentatus by January.
From July onwards, after leaving the nest, the mantle and upper scapulars are moulted to second generation feathers, normally showing an anchor pattern and a dark base. The lowest row of scapulars, especially the rear feathers, are still juvenile or actively moulted by March in most 2cy birds (contra e.g. michahellis, which has finished the replacement in the lowest row). The notched pattern of the juvenile tertials, lesser, lower lesser and median coverts is not very obvious anymore by February, as the white parts are largely worn away. The juvenile greater coverts show a 'piano-key' pattern in argenteus; on the outer greater coverts as well. 
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.

2 images: Herring Gull JXOS 2cy (argentatus), November 06 2004, Westkapelle, the Netherlands (51.33N-03.25E). Picture Pim Wolf.

Again, in winter this Herring Gull from Norway can be found along the Dutch coast. Most feathers are still second generation-like by November. The bill has a black tip and culmen, the iris is brown and the tail-pattern is typical for so-called "second winter" birds. The new inner greater covert in the right wing is a third generation grey-based feather.