Albert de Jong
Larus cachinnans hybrid 3CY XTFX January 23 2017, Scheveningen, the Netherlands.
Green XTFX and metal DEH Hiddensee EA-203086, ringed as pullus on June 09 2015 in a mixed colony of Gräbendorfer See - Brandenburg, eastern Germany (51,42N 14,06E). Location holds a mixed colony of argentatus and cachinnans mostly.
In this bird, strong dominance of cachinnans: advanced partial autumn moult, flat gonys angle,and head shape. Streaked head and pattern on GC and LC batter match Herring Gull or even Yellow-legged Gull.