It was ringed on October 07 2002 at IJmuiden (52.28N 04.35E) as 2cy; released after being held in captivity for more than 24 hours. Upper-part grey tone in combination with iris colour, facial expression and size advocate sub-species argentatus, but could be bulky male 4CY argenteus. This bird resembles an adult in many respect, but the black markings on the bill are too extensive for full adult birds. Note also the dark marking in R6 (outer tail-feather), the brown diffuse markings on the central greater coverts, pink-based bill and dark orbital ring. The primary moult score: P8 fully grown. Bottom image shows greater primary coverts and pattern on P5.

From June (often mid-May in France, Belgium and the Netherlands) to October, a complete moult will bring birds in so-called "sub-adult winter" plumage. A new set of primaries will grow during the summer months and by October, the old primaries are all shed in argenteus in the Netherlands and northern France. In most adults (!), the new primary P6 is just visible beneath the tertials and shows a clear sub-terminal band. By late-September, P6 and P7 are fully-grown as well. At the same time, almost all wing-coverts have been renewed. In summer, the head is still largely white, but by September, most birds develop extensive 'winter streaking', in sub-adults strongly mottled brown contrasting with the white breast as in an executioner's hood. The tertials show obvious white tips. The iris is white-yellow with extensive speckling. The bill has a red gonydeal spot confined to the lower mandible. The orbital ring is yellow-orange in most argenteus, but often dark in autumn.