Exif Keywords: Exif ImageDescription: The Black Swan, Cygnus atratus is a large waterbird which breeds mainly in the southeast and southwest regions of Australia. ...
The Black Swan is common in the wetlands of south western and south eastern Australia, Tasmania, and adjacant coastal islands. In the south west the range ecompasses an area between North West Cape, Cape Leeuwin and Eucla; while in the south east it covers are large region bounded by the Atherton Tableland, the Eyre Peninsula and Tasmania, with the Murray Darling Basin supporting very large populations of Black Swans. It is uncommon in central and northern Australia.
The Black Swan’s preferred habitat extends across fresh, brackish and salt water lakes, swamps and rivers with underwater and emergent vegetation for food and nesting materials. Permanent wetlands are preferred, including ornamental lakes, but Black Swans can also be found in flooded pastures and tidal mudflats, and occasionally on the open sea near islands or the shore.
Black Swans were once thought to be sedentary, but the species is now known to be highly nomadic. There is no set migratory pattern, but rather opportunistic responses to either rainfall or drought. In high rainfall years, emigration occurs from the south west and south east into the interior, with a reverse immigration to these heartlands in drier years. When rain does fall in the arid central regions, Black Swans will migrate to these areas to nest and raise their young. However, should dry conditions return before the young have been raised, the adult birds will abandon the nests and their eggs or cygnets and return to wetter areas.
Black Swans, like many other water fowl, lose all their flight feathers at once when they moult after breeding, and they are unable to fly for about a month. During this time they will usually settle on large, open waters for safety....Black Swans are mostly black feathered, with a line of white flight feathers of the wing edges that sometimes show when at rest, and are conspicuous in flight. 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 1.1 and 1.4 metres in length and weighs up to 9 kg. Its wing span, in flight, is between 1.6 and 2 metres.The neck is long (relatively the longest neck among the swans) and curved in an "S".
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. 
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 beatWhen 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
Generally, Black Swans nest in the wetter winter months (February to September), occasionally in large colonies. A typical clutch contains 4 to 7 greenish-white eggs that are incubated for about 35-40 days. After hatching the cygnets are tended by the parents for about 6 months until fledging, and may ride on their parent's back for longer trips into deeper water.
A Black Swan nest is essentially a large heap or mound of reeds, grasses and weeds between 1 and 1.5 metres in diameter and up to 1 metre high, in shallow water or on islands. A nest is reused every year, restored or rebuilt as needed. Both parents share the care of the nest, and once the cygnets are fledged, it is not uncommon to see the parents and young swans looking for food together. Like other swans, the Black Swan is largely monogamous, pairing for life (about 6% divorce rate). Recent studies have shown that around a third of all broods exhibit extra-pair paternity.Source:Wikipedia
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