2cy (argenteus), August 14 2008, IJmuiden, the Netherlands.
A 2cy argenteus,
ringed in the Netherlands, ring number Arnhem 5.352.714. It was ringed as pullus on July 02 2007 at IJmuiden (52.28N 04.35E). Moult score: P7 fully grown, P9-P10 old. Secs and recs not scored. Tt1 old 2g, tt2-5 2g, tt6 nn. Gc1-19 2g, gc19 last visible. Mc1-17 2g, mc17 last visible. Llc1-17 2g, llc17 last visible. Lc probably no old juv feathers, all 2g and/or missing/growing. Left side: us 0-25% new 2g-like, ls 100% old 2g-like.
From 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 appears white from
May to July, will be moulted by July-August and will show neat fine
streaking by October. The under-parts and rump turns pale, mottled with
brown. From mid-April, the scapulars and mantle are replaced by 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, but they can be recognized by the warm buffish
tone and neat white fringe as long as the feathers are fresh. In the second generation scapulars, the
fringes are often worn away (especially in the upper scapulars). 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.
From early April, the inner primaries are shed
and new second generation primaries grown in. The last juvenile primary (P10)
will be shed by the first week of August. The majority of argenteus
complete the primary moult by the first week of October, with a new second
generation P10 fully grown. The new primaries are dark with a tiny pale tip on
the fresh flight-feathers. Again, 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 will show a clear-cut blackish tail-band with only isolated
blackish markings on the white basal half.
From late April, argenteus will replace the wing-coverts and
tertials, starting with the median coverts, upper tertials and innermost greater
coverts. The fresh feathers will be buffish-based with an obvious barred
pattern. By July, the warm tones of the first moulted feathers are faded to
plain white, leaving a contrasting barred pattern on the wing-coverts. The
last coverts to be moulted are the central greater coverts, replaced by
mid-August. The new greater coverts may show a vermiculated, densely barred