Albert de Jong
Larus cachinnans 3P71 adult, May 02 2014, Zastów Karczmiski, Poland. Picture: Łukasz Bednarz ringing team.
Location: Zastów Karczmiski, Poland - colony at the banks of the Middle Vistula river.
Middle Vistule river is a location where several taxa breed: see composition. Since this is a mixed breeding population where hybridisation is not uncommon, the ringing centre in Poland decided to label birds "Larus argentatus sensu lato". Still bulk of the breeding birds in Middle Vistula region show features of cachinnans.
Breeding bird trapped at the nest. Adult, with little speckling in iris. Red orbital ring and gape. No red on upper mandible; obvious black on the upper and on lower mandible.