probable hybrid Herring Gull x Lesser Black-backed Gull 2cy (argenteus x graellsii), October- December 1999, Westkapelle, the Netherlands (51.33N-03.25E). Pictures by Pim Wolf.

About age:
An odd bird, difficult to age. The pale basal half of the bill and the iris which has become slightly paler suggest a so-called "second winter" bird (2cy). More clues can be found in the plumage: all the wing-coverts were moulted last summer, with the inner greater coverts and median coverts replaced first. These coverts are now bleached and most contrasting patterned. The recently replaced feathers show plain grey in the centres. This strongly favor a 2cy bird, over a 1cy bird. 3cy birds would show the typical patterned inner primaries, which are still obvious second generation in this individual. One of the best clues for ageing are the primaries and secondaries. It's hard to tell from the pictures, but the primaries appear dark, blackish, in line with what can be expected in second generation primaries. However, they seem to be pointed, as in juvenile primaries. 

About taxon:
A very chequered and dark first winter bird. The greater coverts, the outer median coverts and lesser coverts are very dark, almost completely lacking a notching pattern as can normally be found in Herring Gulls. About eight of the wing-coverts are predominantly grey, moulted quite randomly. The tail-band is very obvious, almost black and clear-cut from the white rump and base of the feathers. The inner primaries have slightly paler inner-webs, though still not creating a typical window as in 2cy argenteus.
It's hard to rule out a small argentatus from Scandinavia, but in the picture where the wings are raised, the inner primaries show only a limited pale window, with pale inner-webs on P1 to P5. The pale patch doesn't extend to the outer-webs, as is the case in most argentatus. Note also the very dark under-wing coverts, more in line with birds of the LBBG-complex. Another strong clue against a 100% argentatus is the jizz: the short stubby bill, the rounded head, the short legs and the pot-bellied appearance is not particularly in line with the strong, powerful argentatus, which is often obviously heavier built than argenteus. Those characteristics could be indicative for a hybrid.
The darkness of the grey feathers, "medium grey", combined with the delicate appearance could point to a Herring Gull x Lesser Black-backed Gull.

All comments are appreciated.

(October 21 1999)

(October 21 1999)

(December 23 1999)