Black swan

Description

Black swans are mostly black-feathered birds,with white flight feathers.The bill is bright red,with a pale bar and tip;and legs and feet are greyish-black.Cobs (males) are slightly larger than pens (females),with a longer and straighter bill.Cygnets (immature birds) are a greyish-brown with pale-edged feathers.A mature black swan measures between 110 and 142 centimetres (43 and 56 in) in length and weighs 3.7–9 kilograms (8.2–19.8 lb).Its wing span is between 1.6 and 2 metres (5.2 and 6.6 ft).The neck is long (relatively the longest neck among the swans) and curved in an "S"-shape.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,a wedge of 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 black swan is unlike any other Australian bird,although in poor light and at long range it may be confused with a magpie goose in flight.However,the black swan can be distinguished by its much longer neck and slower wing beat.