Gulls in NW Europe
(last update: September 25, 2011
Herring Gull (argenteus) E adult, November 2002 - October 2017, Scheveningen, the Netherlands.
Ringed white E, like several other birds and therefore not to identify individually (but most likely this single bird lingers around most of the year). Upperpart grey tone indicative for local origin.
below: E (argenteus) October 22 2017, Scheveningen, the Netherlands.
below: E (argenteus) October 31 2016, Scheveningen, the Netherlands.
below: E (argenteus) October 22 2012, Scheveningen, the Netherlands.
Ring getting old.
below: E (argenteus) November 10 2011, Scheveningen, the Netherlands.
P8 fully grown, P9 reaches P8 tip.
below: E (argenteus), October 11 2011, Scheveningen, the Netherlands.
P6 fully grown; no old primaries left. Active moult in rectrices.
below: E (argenteus), April 25 2003, Scheveningen, the Netherlands.
The scapulars, the wing-coverts and the tertials appear completely adult-like grey. The primaries show a clear mirror on both P9 and P10. The outer primary-covert are dark centred, unlike the grey adult-like primary-coverts of adult birds. In most near-adults the primary coverts are not completely grey but still show a black centre in the outermost greater primary coverts. The tail-feathers are all white.
From January to April, sub-adult and adult argenteus moult to so-called "summer plumage" and this bird clearly shows missing feathers around the eye, accentuating the yellow-orange orbital ring. By April, the head and under-parts appear all-white. The tail-feathers, wing-coverts and primaries are not replaced in this partial spring moult, therefore most birds strongly resemble "winter birds", although the white primary tips wear away and dark patches start to bleach. The iris turns bright yellow in many sub-adults, the orbital ring turns yellowish-orange and the bill will become predominantly yellow with a red gonydeal spot and limited black markings along the culmen by April.
below: E (argenteus), November 15 2002, Scheveningen, the Netherlands.
A 4cy argenteus ringed in the Netherlands as pullus at Maasvlakte, about 15 km from Scheveningen. In many respect this bird resembles an adult with an obvious mirror on P10 and all grey upper-parts, wing-coverts and tertials. The bill has a clear immature dark bill-band.
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.