Great Black-backed Gull (Larus marinus) 2cy, February 18 2007, IJmuiden, The Netherlands.
US: 1-25%, LS: 0%, TOT SCAPS: 1-25%. Note active moult in lowest row of upper scapulars (lus), and white crescent tips of primaries still present.
Wing-coverts and tertials still juvenile. Compare size to Herring Gull in front.