Great Black-backed Gull (Larus marinus)

(last update: July 12, 2015)

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

Great Black-backed Gull (Larus marinus) 3CY, July 30 2014, IJmuiden, the Netherlands.

Immature bird in complete moult: P6/P9. Active moult in other feather tracts as well, prominent in coverts which are replaced for fresh dark feathers. Old P10 without mirror (indication for 3CY age); old 2nd gen secondaries with brownish centres and vermiculated along edges.