Great Black-backed Gull (Larus marinus)

(last update: October 12, 2011)

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

Great Black-backed Gull (Larus marinus) 4cy: January 13 2012, IJmuiden, the Netherlands.

Scapulars, median coverts and tertials show adult-like greyish black colour. Primaries with obvious white tips and distinct mirror on P10 and P9. Still many vestiges of immaturity in several feather tracts indicate 4cy.