Herring Gull (argentatus & argenteus)

(last update: February 11, 2013)

Herring Gull 5CY, March 10 2014, Katwijk, the Netherlands.

Very adult-like flight feathers. Last vestiges of immaturity in greater primary coverts (and sometimes dark marking on tail of coverts; often slightly more black on bill than in true adults).

Only very rarely no mirror on P10, but here no mirror on left P10.