Herring Gull - Zilvermeeuw (argentatus & argenteus)
(last update: 30 maart 2004)
(5 images) Herring Gull CV106 6cy (argentatus), July 15-16 2003, Tampere, Finland (61.31N, 23.43E).
6cy argentatus white CV106,
ringed as pullus on June 28 1998 in Pälkän, Finland (61.30N 24.13E). From
2001 onwards, there are about 35 observations, all from Tampere dump.
From June to December, adult argentatus
undergo a complete moult resulting in so-called "winter
plumage". By August, the first neat streaks can be found on the crown
and hind-neck. After the complete moult is finished by late autumn, the
head will often show extensive 'winter streaking'.
During the summer, the primaries are moulted. In adult argentatus, the last outer primary P10 will be fully grown by January in the most northern population, by early December in southern populations, about equal to West-European argenteus.
Adult northern argentatus show a
different pattern in the outer primaries, compared to argenteus. In
argentatus, especially from northern Scandinavia, the black markings
on P5 are limited or absent and, if black on P5 is present, this black has
diffuse edges. Most often, these black sub-terminal markings are completely
lacking on P5. In Baltic argentatus, black on P5 is normally confined to the outer-web, with sharply defined