Great Black-backed Gull (Larus marinus)

(last update: July 12, 2015)

Great Black-backed Gull (Larus marinus) sub-adult, May 17 2002, Le Portel - Boulogne sur Mer, France (50.42 N - 01.34 E).

Ageing GBBG may be difficult in some plumages, but this one is pretty straightforward. The large white tips on the dark centred secondaries and the conspicuous white mirror on p10 rule out a 3cy bird in spring. The abraded brown greater coverts, the black shaft in the outer tail-feathers, the black bill-band and the very immature primary coverts make it very unlike to be in 5cy already so ageing this bird as 4cy or sub-adult is pretty safe.