Albert de Jong
Larus argentatus sensu lato 3P27 adult, April 22 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.
Here, feature point to adult Herring Gull argentatus. Breeding bird trapped at the nest. Adult, with yellow legs, large mirror on P10, medium pale tongue on P10, about 50% black on outerweb of P8, small black spot on P5, red gape, red orbital ring, heavy bill with obvious gonys and only hint of red bleeding up onto the upper mandible.