Larus cachinnans 2CY XJCM March 31 2012, Gouda, the Netherlands. Picture: Johannes Luiten.
Bird ringed green XJCM, (data pending) probably ringed as Yellow-legged Gull (Larus cachinnans ssp.). Ringed as pullus on June 11 2011 at Klein Partwitz Bautzen Sachsen, Germany (51,51579 14,15828).
Strongly recalling pure cachinnans, although origin from mixed colony: white head, Venetian blind in inner primaries, tail pattern, bill.