July 10 & 11 2002, Boulogne/Mer,
A 2cy argenteus, ring number Bruxelles H
- 117771, ringed as pullus on July 16 2001 at Zeebrugge (51.20N 03.11E). 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 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
The primary moult score
of H - 117771: P6 is fully grown and P9-P10 are still juvenile.
The four upper tertials have been replaced and the two lower tertials are
still juvenile. The greater and median coverts have been moulted, with
greater coverts #6 and #7 still falling short. The lower lesser covert row
is a mix of one retained juvenile feather, fresh second generation
feathers and growing feathers in the outer row. About 50% of the lesser
coverts have been renewed, but still some juvenile feathers can be found
in the upper row and in the carpal edge. The fresh third generation
scapulars show a warm buffish base.
was also present on April 19 2002 and by then showed no wing-covert
moult (all wing-coverts old juvenile), two upper scapulars were moulted to
third generation feathers and one upper scapulars was missing. The primary
moult score by April 19: all primaries still juvenile.