Images of Great Black-backed Gulls Larus marinus in the port of IJmuiden, the Netherlands, 19 February 2016.
Second-calendar year with juvenile scapulars (a 2nd-calendar year Herring Gull looks on):
Second-calendar year with Danish ring Black JZA88:
Second-calendar year with Norwegian ring Black JU963:
Third-calendar year with Norwegian ring Black JZ413 (note the faint mirrors on P10:
Another image of Black JZ413, fighting with 2nd-calendar year Black JZ583 while a Herring Gulls steals the fish behind him. Black JU963 comes over to have a look (top left):
JZ413 has some kind of growth on the top of his head:
And to end this post some nice looking adults: