Herring
Gull 1036
2cy (argenteus), December 24 2004, Westkapelle,
the Netherlands (51.33N 03.25E). Picture by Pim Wolf.
An
orange ringed argenteus, probably ringed in the York project, U.K.
A few new scapulars appear rather pale plain grey, but most feathers are
second generation-like showing bars and anchors. The bill is typical for 2cy
birds. The second generation primaries are dark brown and the
tips are very limited.
After the complete moult, a partial moult started in September and
included several wing coverts (see e.g. the inner greater coverts) and the
upper tertials. These feathers appear fresher in the wing.
The complete moult in argenteus is
finished by October and overlaps with the partial autumn moult. Between
September and November, the average 2cy argenteus start a
simultaneous partial autumn moult in the wing-coverts, including the upper
tertials, some median and lower lesser coverts and often the inner greater
coverts.
The head shows neat fine streaking and the under-parts and rump are pale,
mottled with brown. The scapulars and mantle are replaced for third
generation feathers, finishing with the replacement of the rear lowest
scapulars. The pattern of these third generation scapulars is more or less
similar to the anchor pattern of the second generation feathers.
Simultaneous with replacement of the lowest scapulars, argenteus
moult some of the lower upper scapulars in November. By October, argenteus
the new scapulars may appear adult-like pale grey or grey-based.
By early October, argenteus finish
the complete moult, with the central greater coverts and outer lesser
coverts moulted last. By December, argenteus has finished the
primary moult. The second generation tail-feathers show a clear-cut
blackish tail-band with only isolated blackish markings on the white basal
half.
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