swan - stately heavy-bodied aquatic bird with very long neck and usually white plumage as adult

genus Cygnus, Cygnus - a genus of Anatidae

Cygnus columbianus columbianus, whistling swan - North American subspecies of tundra swan having a soft whistling note

Bewick's swan, Cygnus columbianus bewickii - Eurasian subspecies of tundra swan; smaller than the whooper