Trumpeter Swan Cygnus buccinator

The Trumpeter Swan is the largest of all swans. It is native to North America (equivalent of Eurasian Whooper Swan, but a bit larger; similar trumpeting sound but louder).

It has a fully black beak.

The head and body of the adult swan is all white (often with some staining from mud); . . .

. . . those shown here with some greyish-brown plumage are juveniles (sub-adults).