Great Black-backed Gull (Larus marinus)

(last update: July 12, 2015)

Jean-Michel Sauvage (France)
Morten Helberg (Norway)
Nils Helge Lorentzen (Norway)
Mars Muusse (Netherlands)

Great Black-backed Gull (Larus marinus), sub-adult, September 24 2015, IJmuiden, the Netherlands.

Small diffuse, but obvious mirror on old P10 indicate 3Cy age. Hard to exclude immature looking 4CY bird. Complete moult: P6/P9.