Albert de Jong
Larus argentatus sensu lato 3P14 adult, April 17 2014, Wytyckie Lake - Urszulin, Poland. Picture: Łukasz Bednarz ringing team.
In the middle range of the Vistula river, mixed breeding populations can be found where hybridisation is not uncommon. Therefore the ringing centre in Poland decided to label birds "Larus argentatus sensu lato", rather than being specific on argentatus, cachinnans or michahellis. Still bulk of the breeding birds in Middle Vistula region show features of cachinnans.
For 2012, Wytyckie breeding location of 150 pairs cachinnans, of which 54 adults ringed and 158 pulli in 2012 (pers comm. Łukasz Bednarz).
Breeding bird trapped at the nest. Few odd features for pure cachinnans. Adult, with deep tongue on P10 not ending square and black on innerweb running up all the way to coverts; limited black on P5; no black on outerweb of P4. Limited speckling in iris. Coral red orbital ring and gape; red also on upper mandible of saturated yellow bill. Yellow legs.