Albert de Jong
Larus argentatus sensu lato 3P78 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.
Probably at least some cachinnans influences.
Breeding bird trapped at the nest. Adult with powerful bill and relatively broad medial band. Very little speckling in the yellow iris. Red orbital ring and gape. Faint red on upper mandible; small black mark on the upper mandible.