Mergus merganser merganse
This bird was alone, swam a bit, and flew away. Size: mallard, short neck(in comparison to a mallard), head and back black and shimmering blue and green, feet and beak are red; the beak is narrow, and has a downward hook at the end, the tail was short, feet located at the end of the torpedo-shaped body. Oh, and the wings are compact, shorter than a mallard's.
this is a male