When one thinks of a swan, one usually thinks of a large, graceful, white bird, swimming in a pond—and it's always swimming (isn't it?), or resting elegantly on land...not walking or flying. Or, of course, the "ugly duckling" of Hans Christian Andersen fame. And the swan is almost always "white." That's just the color one sees when one imagines a swan. But not this swan.
The black swan (Cygnus atratus, from words meaning "swan" and "dressed in black") is one of the seven (or eight) species of swan, the largest of the waterfowl. They are part of the Order Anseriformes (waterfowl: ducks, geese, swans) and the Family Anatidae (subfamily Anserinae). Anser is Latin for "goose" and anas the same for "duck." While the bird is really only native to Australia and Tasmania, it has been introduced (and been successful) in New Zealand. Additionally, it has found a home all over the globe on private land, city parks, and in zoos—despite the swan's place in many a glass menagerie, it is a hardy bird that can do well in a number of climates.
Discovered around western Australia by the Dutch in 1697 and brought back to Europe soon after, the black swan has become—perhaps partly due to its not looking like a typical swan—one of the most popular species of the bird. In the wild, it lives in open waterways where it has plenty of room and plenty of room to look for food. Swamps or lakes with an abundance of vegetation, at or below the surface are preferred.
Swans don't dive, but they do use their long necks to reach below the water to get the plants on which they depend. Because they have long necks they are able to coexist with other waterfowl (notably ducks) without much competition for food (though this isn't always the case with all species of swan). Their diet consists primarily of aquatic vegetation of all kinds, though they also eat plants and grain found on land (occasionally water insects). Feeding is generally done at dusk.
Details:
Length: 1.1 to 1.4 m (3.6 to 4.6 feet)
Wingspan: 1.6 m to 2 m (5.24 to 6.56 feet)
Weight: up to 9 kg (20 lbs.)
There is some sexual dimorphism with the male somewhat larger than the female.
The bird has a red-orange beak with a white spot or band near the tip and bright red eyes. And while the bird has earned its name, it does have white flight feathers that can only be partially seen when at rest (if at all). Cygnets (the young) are grey or brown in appearance and have a dark or black beak. Both young and adult black swans have grey or black legs/feet.
The black swan's (as with all swans) long neck is due to extra vertebrae in comparison with its relatives. Besides as an adaptation for getting food, it enables the swan to have that graceful curve for which it is renowned. Only two species of swan have the truly "classic" curve, the black swan being one of them (the other being the mute swan). Other species tend to hold their necks in a more vertical position. As the bird swims, it tends to hold its wings—"elbows," as one source puts it—up slightly (a characteristic also shared by the mute swan). Sometimes the cygnets will ride on the back, between the wings.
This mostly non-migratory bird tends to nest in colonies. June or July is usually the mating season in the wild, though in the Northern hemisphere it has been seen to happen at various times of the year. Nests are built near the water (sometimes even partially on the water) and made of grasses and reeds which are placed (not really arranged) until a mound of sufficient size is made (as much as 1.5 m/5 feet across). Then the weight of the parents presses down the mound, making it firm and stable.
The female then makes a depression where the clutch of five to eight greenish-colored eggs will be laid (about a day apart). After done, the parents will take turns incubating them for around thirty-five days. When the parent(s) leave the nest, the eggs are covered with grass and reeds to keep them insulated.
After birth, the young remain close and eat the same food as the parents, foraging on their own once they have been shown what to eat. The young first fly at about two months but take long in leaving the care of the parents, usually not until the next mating season, after which they will join a small flock or pair up with a mate. Sexual maturity comes at the third year. Black swans will sometimes pair up as much as two years before actual breeding begins. Like most (but not all) swans, they mate for life—sometimes for as many as forty years.
Though the least territorial of the swans, the black swan will aggressively defend the nest and its young against any intrusion or perceived danger, including humans.
(Sources: www.chaffeezoo.org/zoo/animals/blk_swan.html
www.auburnweb.com/paradise/birds/black_swan.html
www.scz.org/animals/s/bswan.html, www.britannica.com)