Gull 5.365.172 2cy (argenteus), October-November 2002, Brouwersdam, the Netherlands (51.45N-03.52E).
This Dutch 2cy argenteus
was ringed as pullus by Roland-Jan Buijs, at the industrial emplacement "Vlissingen-Oost
/ Quarleshaven" in the SW of the Netherlands on June 30 2001. From
the first month after fledging, this bird was seen at Brouwersdam on
From late April onwards, argenteus has a complete
during summer to so-called "second winter" plumage. This
complete moult will be 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 has been moulted in July-August and shows neat fine
streaking by October. The under-parts and rump are pale, mottled with
brown. From mid-May, the scapulars and mantle were replaced for third
generation feathers, starting with the replacement of the lower upper
scapulars. The pattern of the third
generation scapulars is more or less similar to the anchor pattern of the
second generation feathers. By October, argenteus
acquire some new adult-like pale grey scapulars.
From early April, the inner primaries
and new second generation primaries grown in. On average, the last juvenile primary (P10)
was shed in the first week of August. The majority of argenteus
complete the primary moult by the first week of October, when the new second
generation P10 will be fully grown. The new primaries are dark with a tiny pale tip on
the fresh flight-feathers. The four inner primaries show an extensive
pale window, as both inner and outer-web are pale greyish white-brown,
contrasting with the outer-wing. A pale inner-web can still be found in P7.
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
This 2cy argenteus
has P10 fully grown. All
rectrices and secondaries are fully grown as well, replaced by second
generation flight-feathers. This Dutch 2cy argenteus
is illustrative for argenteus replacing wing-coverts in the partial
moult: the two upper tertials,
the two inner greater coverts, the second median covert (#2) are all
replaced for third generation feathers recently. The new feathers are
easily recognized by the warm grey-buff centres and the neat fringe.
image above: 5.365.172 2cy,
October 19 2002, Brouwersdam, the Netherlands (51.45N-03.52E).
image below: 5.365.172 2cy,
November 02 2002, Brouwersdam, the Netherlands (51.45N-03.52E).
The same individual, two weeks later. As
can be seen in the image, the average final partial moult stage will be
reached by October.