(11 images) Herring Gull H - 113894 (argenteus), July 2002 - March 2003, Boulogne/Mer, France (50.43N-01.37E).

A 2cy argenteus, ringed in Belgium, ring number Bruxelles H - 113894. Ringed as pullus on July 13 2001 at Zeebrugge, Belgium (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 primary moult score of H-113894 at July 10: P6 is missing and P7 is still juvenile in the left wing and P6 still present in the right wing.
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 pattern.
In H-113894, the two upper tertials are replaced and the third tertial is growing. The lower tertials are still juvenile. The inner four greater coverts have been moulted and most of the central greater coverts are missing. Single juvenile greater coverts are retained juvenile. The median coverts show fresh moulted feathers in the inner-arm, but the outer median coverts are still missing. The lower lesser covert row is almost closed with the last feathers still growing, obvious in the outer row. About 75% of the lesser coverts have been dropped but a few are still juvenile, mainly in the upper row and in the carpal edge.

H-113894 was also present on April 19 2002 and by then, all wing-coverts were old juvenile. One upper lower scapular was replaced by a third generation feather and two upper scapulars were missing. The primary moult score by April 19: only P1 was missing.

3 images below: H - 113894 2cy, July 10 & 11 2002, Boulogne/Mer, France (50.43N-01.37E).

3 images above: H - 113894 2cy, July 10 & 11 2002, Boulogne/Mer, France (50.43N-01.37E).

3 images below: H - 113894 2cy, October 03 & 04 2002, Boulogne/Mer, France (50.43N-01.37E).

By early October, P8 is fully grown and P9-P10 are still growing. All rectrices and secondaries are fully grown second generation feathers. This 2cy argenteus started the partial moult, as the two upper tertials are missing again. They will be replaced for third generation feathers. One lower lesser covert is growing. In the scapulars, a few rear lower upper scapulars are missing.

3 images above: H - 113894 2cy, October 03 & 04 2002, Boulogne/Mer, France (50.43N-01.37E).

1 image below: H - 113894 2cy, October 24 2002, Boulogne/Mer, France (50.43N-01.37E).

By the end of October, P9 is fully grown and P10 is still growing. All rectrices and secondaries were already fully grown second generation by early October. The partial autumn moult is well in progress now: the upper tertial is new, tertial #2 is growing, greater covert #4 is growing, median covert #2 is new and the other coverts are old second generation feathers. About 40% of the scapulars are grey now.

2 images below: H-113894 3cy, February 07 2003, Boulogne/Mer, France (50.43N-01.37E).

A typical 3cy argenteus ringed in Belgium: Bruxelles H-113894. The blackish-brown second generation primaries lack a mirror on P10 and note the pattern of the inner primaries in the second image below. The second generation tail has a broad dark tail-band.
Note the progress in grey scapulars between October (2cy) and February (3cy). The new scapulars are more or less uniform pale grey, contrasting with the old patterned brownish feathers left in the rear upper and lower scapulars.
This Belgian individual has moulted tertials and a few wing-coverts have been replaced to third generation feathers in the partial autumn moult: the two upper tertials are obvious fresher than the adjacent feathers. These feathers were still growing in October. The greater covert #4 has been replaced as well and also one lower lesser covert and one lesser covert. Note that the outer median and lower lesser coverts are missing in this individual. The new feathers have fresh fringes and tips but the patterns of new tertials and greater coverts is very similar to the second generation feathers, although they are typically grey-based with faint sub-terminal markings and a pronounced shaft streak.

2 images below: H-1138943cy, March 17 2003, Boulogne/Mer, France (50.43N-01.37E).

3cy argenteus has a partial moult in spring. It starts in January and is completed by April, leaving birds in so-called "second summer" plumage. The head turns white, especially on throat, breast and belly. By April, the scapulars and mantle will show many adult-like grey feathers, often creating a contrasting "grey saddle", as most of the wing-coverts (especially the lesser coverts) are still barred. The old second generation wing-coverts start to fade and the fringes wear off. 
The iris and base of the bill turn pale yellow, although some individuals show a warm amber iris. The bill shows some red on the gonydeal angle and it still shows an obvious dark bill-band.