Herring Gull - Zilvermeeuw (argentatus & argenteus): sub-ad September

(last update: 22 september 2004)

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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 Jan.
HG sub-ad Feb.
HG sub-ad March
HG sub-ad April
HG sub-ad May
HG sub-ad June
HG sub-ad July
HG sub-ad Aug.
HG sub-ad Sept.
HG sub-ad Oct.
HG sub-ad Nov.
HG sub-ad Dec.

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(2 images) Herring Gull (argenteus)4cy, September 21 2004, Scheveningen, the Netherlands.

4cy argenteus with obvious dark tertial spots. Primary moult score: P7 fully grown. 

From June (often mid-May in France, Belgium and the Netherlands) to October, a complete moult will bring birds in so-called "sub-adult winter" plumage. A new set of primaries will grow during the summer months and by October, the old primaries are all shed in argenteus in the Netherlands and northern France. In most adults (!), the new primary P6 is just visible beneath the tertials and shows a clear sub-terminal band. By late-September, P6 and P7 are fully-grown as well. At the same time, almost all wing-coverts have been renewed. In summer, the head is still largely white, but by September, most birds develop extensive 'winter streaking', in sub-adults strongly mottled brown contrasting with the white breast as in an executioner's hood. The tertials show obvious white tips. The iris is white-yellow with extensive speckling. The bill has a red gonydeal spot confined to the lower mandible. The orbital ring is yellow-orange in most argenteus, but often dark in autumn.