Herring Gull- Zilvermeeuw (argentatus & argenteus)

(last update: 8-2-2007)

Herring Gull 3cy (argentatus), January 04 2002, Le Portel / Boulogne-sur-Mer, France (50.42N,1.34E).

A 3cy argentatus, showing more or less plain grey upper scapulars and a vermiculated pattern on most of the wing-coverts and tertials. In this respect, it somewhat resembles argenteus. 
In many argentatus, the scapulars show a delicate fine black pattern on a very pale base by January. The new third generation upper scapulars are not plain adult-like grey as in most argenteus, but the third generation feathers strongly resemble second generation feathers. Compared to argenteus, argentatus may show finer, more delicately black-patterned feathers, not as bold and smudgy as many argenteus show (especially in the second generation central greater coverts).
Note the primaries with rounded tips, clearly second generation feathers and unlike the pointed juvenile remiges. Looking closer, P10 shows a faint mirror, a feature definitely lacking in juvenile feathers. Second generation primaries with a mirror on P10 can be found in quite some argentatus (and is very rare in argenteus).

This individual has replaced none of the wing-coverts in the partial autumn moult as 2cy bird. Note the Glaucous Gull-like bill.
(In the back: two Mediterranean Gulls and a yellow-legged Common Gull).