Herring Gull- Zilvermeeuw (argentatus & argenteus)

(last update: 27-12-2006)

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Herring Gull plumages:

hg 1cy July
hg 1cy August
hg 1cy September
hg 1cy October
hg 1cy November
hg 1cy December

hg 2cy January
hg 2cy February
hg 2cy March
hg 2cy April
hg 2cy May
hg 2cy June
hg 2cy July
hg 2cy August
hg 2cy September
hg 2cy October
hg 2cy November
hg 2cy December

hg 3cy January
hg 3cy February
hg 3cy March
hg 3cy April
hg 3cy May
hg 3cy June
hg 3cy July
hg 3cy August
hg 3cy September
hg 3cy October
hg 3cy November
hg 3cy December

hg sub-ad January
hg sub-ad February
hg sub-ad March
hg sub-ad April
hg sub-ad May
hg sub-ad June
hg sub-ad July
hg sub-ad August
hg sub-ad September
hg sub-ad October
hg sub-ad November
hg sub-ad December

hg ad January
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hg ad December

(2 images) Herring Gull 4.238.828 2cy (argenteus), 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). This 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 buffish centres. 

From early April, the inner primaries were shed 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 coverts.

(September 30 2002)

image above: 4.238.828 2cy, 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)