Herring Gull - Zilvermeeuw (argentatus & argenteus): sub-adult Nov.
(last update: 08 december 2003)
Herring Gull adult 5.038.584 November 2003 & October 2009, Westkapelle, the Netherlands (51.33N 03.25E).
A sub-adult with a Dutch ring 5.038.584.
Ringing data: Arnhem.5038584, ringed as: >4 cy unknown sex, on 23-5-2002, at Vlissingen-Oost (Quarleshaven), Zeeland, NL (5128.00 N 342.00 E), by Roland-Jan Buijs.
Herring Gull adult5.038.584 October 01 2009, Westkapelle, the Netherlands (51.33N 03.25E).
Herring Gull adult 5.038.584 November 15 2003, Westkapelle, the Netherlands (51.33N 03.25E).
The primary coverts still show some black markings. The complete moult has been finished: P10 is fully grown. P10 shows a complete black sub-terminal band. The bill has some black on both upper and lower mandible.
From June to October, sub-adult Herring
Gull have a complete moult to so-called "winter plumage".
As long as the old outer third generation primaries are visible (until
August), ageing as 4cy is rather straightforward. From November onwards,
4cy birds much resemble adult birds, except that the bare parts still show
immature features: the black bill-band is obvious, extending over both
upper and lower mandible. On average, this plumage develops a more
pronounced winter 'hood' than in full adults: dense streaking on head,
especially around the eye and in the hind-neck. The upper-parts,
wing-coverts and tertials appear adult-like grey from 4cy October onwards.
The fourth generation tail-feathers are plain white.