Herring Gull- Zilvermeeuw (argentatus & argenteus)

(last update: 9-2-2007)

(2 images) Herring Gull H-112486 3cy (argenteus), March 15 2003, Le Portel / Boulogne-sur-Mer, France (50.42N,1.34E).

A typical argenteus, ringed as pullus on July 09 2001 at Zeebrugge, Belgium (51.20N 03.11E), Bruxelles H-112486. The new scapulars are plain adult-like grey, contrasting with the barred lesser coverts and creating a saddle. The bill is typical for 3cy birds in March, pinkish base and a broad bill-band. Note the rather brown second generation primaries lacking the mirror on P10. The tail is completely second generation, showing a broad band. Compared to Scandinavian argentatus, the general impression resembles argentatus in 4cy, which also show an almost complete grey scapular region and single grey feathers in the tertials, inner greater coverts and a few lesser coverts.
The moult-stage is sometimes difficult to interpret in 3cy argenteus by March. The scapulars are more or less uniform grey with just a few patterned brownish feathers left. Many grey scapulars appear abraded at the fringes already, especially in the upper scapulars.
This Belgian individual has moulted a few tertials and wing-coverts in the partial autumn moult as 2cy bird: tertials #1-2 have been replaced, greater coverts #1-2 have been replaced, median coverts #1, #3-4 & #7-9 have been replaced; lower lesser coverts #3, #7 & #9-10 have been replaced, Also, four lesser coverts were moulted. The new feathers have fresh fringes and tips and are more adult-like in their patterns, most are completely grey.

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.