Putative European Eider ssp. mollissima featuring a certain degree of northern borealis characters; not quite the full monty though.
The adult male in the video has a rather short and high bill with convex upper mandible; lacks the bulbous forehead of typical ssp. mollissima; has a steeper forehead-bill profile and squarer overall head shape than typical ssp. mollissima; has broader frontal lobe than nearby ssp. mollissima and orangey mustard-yellow colour on the basal half of the bill, with the outer half and nail being greyer in colour.
These are all characters associated with northern subspecies like borealis, but it lacks obvious white sails supporting a northern origin; yet worth documenting.
The European Eider ssp. mollissima is more than a playmate to the odd King Eider, but is also worth scrutinising more carefully for the subtle features of vagrant forms, chiefly ssp. borealis but also even rarer arctic and Nearctic stragglers. Features such as scapular sails in both sexes, orange bill tones and extra green facial patterning are the clues to the prizes.