Albert de Jong
Larus cachinnans 1CY PHZK October 28 2011, Deponie Pohlsche Heide - Minden, Germany (52°23'05N, 08°46'45E). Picture: Armin Deutsch.
Yellow PHZK and metal PLG DN-27629; ringed as pullus on May 26 2011 at Kozielno, Paczkow, S-SW Poland, (50°29' N, 16°58' E).
In this area are mixed breeding colonies (near Katowice), with far most birds breeding here are cachinnans, but in this area also records of very few michahellis from the south (e.g. ringed female from Italy) and argentatus from eastern Germany are possible (see PDF).
PHZK is classic cachinnans, you won't get them any easier than this probably. First picture together with green ringed 2CY cachinnans.