Herring Gull (argentatus & argenteus)
(last update: February 11, 2013)
Herring Gull (argenteus) NLA 5.422.338 1CY, August 20 & 23 2008, IJmuiden, the Netherlands (52.27N 04.33E).
1cy argenteus, probable female, ringed in the Netherlands, ring number Arnhem 5.422.338. Ringing date 04 June 2008 at Texel, Jan Ayeslag. A bird with all the scapulars still juvenile, although at least two upper scapulars are missing and the partial autumn moult of juveniles started (second generation upper scapulars 1-25% and lower scapulars 0% score).
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.
