Herring
Gull 5.419.232 2cy (argenteus), December 17 2007, Scheveningen, the Netherlands.
Bird taken into care for more than 24 hours. Released on 11 August 2007. Now, a few months later at Scheveningen harbour.
The
complete moult in argenteus is finished by October and overlaps with the partial
autumn moult which starts in September and often include scapulars, a few
inner wing-coverts and upper tertials. 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 November, 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.
By early October, argenteus
finish the complete moult, with the central greater coverts and outer lesser
coverts moulted last. 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.
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