Herring Gull- Zilvermeeuw (argentatus & argenteus)

(last update: 9-2-2007)

Herring Gull H-120600 3cy, March 17 2003, Le Portel / Boulogne-sur-Mer, France (50.42N 01.34E).

A 3cy Herring Gull, ringed as 2cy female on June 19 2002 at Oostende beach, Belgium (51.14N 02.53E), Bruxelles H-120600. Not necessarily local subspecies argenteus. Normally, 3cy argenteus from the Belgian colonies have the scapulars plain adult-like grey, contrasting with the barred lesser coverts, creating a saddle effect. In this individual, almost all scapulars show an anchor pattern. Typically, 3cy birds in March show a pinkish base to the bill and a broad bill-band. In H-120600 however, the bill is predominantly dark. Note the rather brown second generation primaries lacking the mirror on P10. The tail is completely second generation, showing a broad band.
The moult-stage is sometimes difficult to interpret in 3cy argenteus by March. This Belgian individual has moulted a few tertials and wing-coverts in the partial autumn moult as 2cy bird: tertials #1-3 have been replaced, greater coverts #1-3 have been replaced, most of the inner and central median and lower lesser coverts have been replaced (for anchor patterned or barred third generation feathers).

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.