Herring
Gull - Zilvermeeuw (argentatus & argenteus)
(last update: 08 december 2003)
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Herring Gulladult (argenteus), July 14 2001, IJmuiden, the Netherlands (52.27N-04.33E).
Ringed blue and green on the right leg. Argenteus has a partial moult of body and head in spring. It starts in January (when adults in the Netherlands may already return to the colonies) and is completed by April, leaving birds in so-called "adult summer" plumage. The head is clean white and the white primary tips are slightly worn and the dark patches bleached. Otherwise, this plumage much resembles the "adult winter" plumage. The bare parts are more saturated, as the breeding season has started.
From June (often mid-May in France, Belgium and the Netherlands) to October, a complete moult will bring birds in so-called "adult winter" plumage. A new set of primaries will grow during the summer months and by mid July, the innermost primaries have been dropped in argenteus in the Netherlands and northern France. At the same time, the outer median coverts have been renewed and strongly contrast with the abraded adjacent wing-coverts. In summer, the head is still largely white, but after the complete moult is finished, the head shows extensive 'winter streaking', mottled brown contrasting with the white breast as in an executioner's hood. The scapular coverts are plain grey, lacking white crescents. The tertials show obvious white tips. The iris is yellow. The bill is yellow with a red gonydeal spot confined to the lower mandible. The orbital ring is yellow-orange or orange-red in argenteus. The legs are flesh-pink in Dutch argenteus.