Albert de Jong
Larus cachinnans 1CY UKK L-010369 December 08 2010, Wörth, Austria. Picture: Wolfgang Schweighofer.
1CY Caspian Gull with Ukraine Kiev clip-ring. First letter not sure, but probably "L", and L-010xxx codes are last string used in 2010 (most are L-009xxx).
Few coverts replaced in post-juvenile moult. White head.
Armin Deutsch photographed two metal UKK rings with codes very close to this: L-010265 and L-010275, cachinnans ringed as pullus on June 05 2010 in Kreminchuk Reservoir, Cherkassy O. Ukraine (49°24'00"N, 32°09'00"E).