September 30 - October 17 2002, IJmuiden, the Netherlands (52.27N-04.33E)
A 2cy argenteus
with a German ring, ringed on the island of Helgoland: 4.238.828. Ringed as pullus on 26.06.2001 on Helgoland (54.10N 07.55E).
individual origins from the most eastern argenteus populations,
showing intermediate characteristics, resembling some nominate argentatus.
Note for instance the rather contrastingly
patterned second generation tertials and coverts, which are not typical
for argenteus from SW Netherlands and indicate some nominate argentatus
influences. All wing-coverts are still second generation, none have been
included in the partial moult. Such a partial autumn moult is common in
typical argenteus from SW Netherlands. Note also that plain grey
scapulars are completely lacking. The legs are flesh coloured with a hint
of yellow. In the right wing, P9 is fully grown, but the old juvenile P10
is still in position. In the left wing P10 has been shed and the tip of P9
equals the tip of P8.
From late April onwards, argenteus has a complete moult
during summer to so-called "second winter" plumage. This
complete moult will be finished by October. 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. In argenteus,
some new scapulars may appear adult-like pale grey, but most new
feathers will show an anchor pattern and this still applies on the new
feathers in September. By September, 2cy argenteus is actively
moulting the lowest scapulars, but in the mean time, the upper scapulars
may be moulted again as well. Fresh feathers can be recognized by the
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.
From late April to September, argenteus replace the wing-coverts and
tertials, finishing with the central greater coverts and outer lesser
coverts. By September, 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
(September 30 2002)
image above: 4.238.828
September 30 2002, IJmuiden, the Netherlands (52.27N-04.33E).
image below: 4.238.828
2cy, October 11-17 2002, IJmuiden, the Netherlands (52.27N-04.33E).
Primary moult has continued after
suspension, with in the right wing P9 fully grown and P10 at the length of
P7. In the left wing P9 is fully grown and P10 has the length of P4.
(October 14 2002)