Herring Gull- Zilvermeeuw (argentatus & argenteus)

(last update: 20-2-2007)

(2 images) Herring Gull KCU 3cy (argenteus), May 23 2002, Vuurtorenvlakte - Maasvlakte, the Netherlands (51.59N,04.02E).

This 3cy argenteus was ringed as pullus on July 15 2000 at Orfordness, Britain. It shows the ordinary features for argenteus in May: The scapulars create an all-grey saddle, except some feathers in the lowest row scapulars. The second generation primaries are bleached brown without white tips and lack a mirror on P10. The second generation tail has a broad dark tail-band.

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, creating a contrasting "grey saddle", as most of the wing-coverts (especially the lesser coverts) are still barred. The wing-coverts start to fade and the fringes wear off. 
The iris and base of the bill turn pale yellow, although some individuals (like this bird) show a warm amber iris. The bill shows some red on the gonydeal angle and it still shows an obvious dark bill-band.

This British argenteus has moulted tertials and wing-coverts to third generation feathers in the partial autumn moult as a 2cy bird: the three upper tertials and some of the inner greater and median coverts have been replaced. Those third generation wing-coverts are hard to recognize by May, as the patterns are very similar to the second generation feathers and the feathers are very worn. Note however that the feathers moulted last, are more adult-like in their general appearance, showing a grey base.