Black swans are large birds with mostly black feathers with white flight feathers. The bill is bright red with a pale tip and their legs and feet are greyish-black. Cobs (males) are slightly larger than pens (females) with a longer and straighter bill.
The black swan utters a musical and far reaching bugle-like sound called either on the water or in flight as well as a range of softer crooning notes. It can also whistle, especially when disturbed while breeding and nesting.
When swimming, black swans hold their necks arched or erect, and often carry their feathers or wings raised in an aggressive display. In flight, black swans will form as a line or a V, with the individual birds flying strongly with undulating long necks, making whistling sounds with their wings and baying, bugling or trumpeting calls. The mute swan is a large member of the waterfowl family Anatidae. It is native to much of Europe and Asia and is rarely seen in upper North Africa as a winter visitor. The mute swan was also introduced into North America, Southern Africa and Australia. The name ‘mute’ derives from it being less vocal than other swan species. Measuring 125 to 170 cm (49 to 67 inches) in length, this large swan is wholly white in plumage with an orange bill bordered with black. It is recognizable by its pronounced knob atop the bill.
Despite its Eurasian origin, its closest relatives are the Australian black swan and the South American Black-necked swan. They feed on a wide range of vegetation, both submerged aquatic plants which they reach with their long necks, and by grazing on land.