Herring Gull- Zilvermeeuw (argentatus & argenteus)

(last update: 8-2-2007)

Herring Gull 3cy (argentatus), February 09 2003, Boulogne/Mer, France (50.43N-01.37E).

A 3cy argentatus, which shows anchor patterns on most of the new third generation upper scapulars. Those feathers are plain adult-like grey in most argenteus by February (creating a grey saddle in advanced birds), but they strongly resemble second generation feathers in most argentatus. Consequently, 3cy argentatus may look very delayed in their moult, compared to argenteus in mixed groups and they can sometimes be mistaken for 2cy birds. 
This very powerful and dominant male 3cy argentatus has rather contrasting and delicately patterned second generation greater coverts, a feature often found in argentatus. Argenteus often show a more vermiculated pattern on the central greater coverts.
Note the primaries with rounded tips, clearly second generation feathers and unlike the pointed juvenile remiges.Argentatus may show a strong contrast between pale inner primaries and dark outer primaries and the 'window' created by these pale inner primaries is very obvious.

This individual has replaced some wing-coverts and the upper two tertials in the partial autumn moult as 2cy bird. The new feathers show a greyish hue on the base and have fresh fringes and tips.