 |
|
|
News Bar » |
|
|
|
|
No doubt you were, because swans are definitely graceful and beautiful creatures that attract the attention of many people the world over. Today we decided to introduce you to a cousin of this ‘Ugly Duckling’ who is not at all like the snow white swan portrayed in the story, but a very graceful ‘black beauty’ in the avian world. All of you must be very familiar with the white swans who are regularly featured in many stories, poems, films and drawings. Black swans are somewhat rare and in fact long before the discovery of the existence of black swans, the metaphor ‘black swan’ was used to describe something that could not exist or be true. It was an ancient western concept that all swans were white. This was proved wrong when an English naturalist named Dr. John Latham described a large, black-feathered swan living in Australia, way back in 1790. Since the 17th century discovery, black swans have been a much studied animal species. So, let’s check out what the experts have to say about these black beauties. Often mistaken with the magpie-goose when in flight, during poor light, the black swan (Cygnus atratus) is unlike any other bird in Australia. This large water bird is found in many parts of Australia, mostly in the southeast and southwest regions, but not very common in central and northern Australia. Its preferred habitats extend across fresh, brackish and saltwater lakes, swamps, and rivers which are abundant with either underwater or emergent (new and still developing) vegetation which the birds use as food and nesting material. As they generally prefer permanent wetlands, the black swans can be found even in flooded pastures and tidal mud flats.
Even though this species of water bird is commonly referred to as ‘swans’, the male birds are known as cobs and females are called pens. The young are called pens. The young one called cygnets. The cobs are slightly larger than the pens. A mature black swan between 1.1 and 1.4 metres in length and weighs about 6.9 kgs. The wingspan in flight is around 1.6-2 mts. This species of swans has the longest necks among swans. The long neck takes the shape of the letter S when the birds are eating or relaxing, but when in flight it is generally held erect. When swimming the birds hold their necks either arched or erect. These birds could be seen flying by the numbers in a V formation at speeds of 50 miles (80 kms) per hour. The birds generally fly at night and rest during the day. The swans are completely black feathered except for a line of white flight feathers on the edge of wings which are visible when flying or sometimes when they are at rest. The bill or beak is bright red with a pale or white bar on the tip. The legs and feet (which are webbed) are greyish black in colour. The eyes which are red are outlined by a thin band of white on the lids. Black swans live alone or in loose company, numbering around 100 or 1000 individuals. Closely related to the mute swan and the black-necked swans, these birds were initially placed into a monotypic genus called Chenopis. They communicate by whistling and making ultra musical and far-reaching bugle-like sounds. When in flight too, these birds could be whistling, trumpeting or bugling. They were once thought to be sedentary (staying in one place) birds, but now they are known to be nomadic (wandering) birds. However, they have no set pattern of migration. According to researchers, these large water birds travel from the southwest and southeast of Australia into interior parts of the country during rain fall and vice versa during the drought. They migrate mostly to nest and raise young during rainfall. However, if dry weather returns before the young or cygnets are raised, they’ll abandon the nests, eggs and young to return to wetter areas.Like many other waterfowls, black swans too settle on open waters for safety especially after breeding. The females nest during the wet, winter months (February-September) and this usually takes place in large colonies. The nests which are turned out of reeds, grasses and weeds are about a metre in height and between 1-1.5 mt in diameter. These large heaps or mounds of nests are made in shallow water or on little islands and reused every year, after some restoration or rebuilding is done. A typical clutch consists of 4-8 greenish-white eggs. The eggs are incubated for about 35-40 days. After the eggs hatch, the young are tended by both parents for six months until the fledgelings are able to fend for themselves completely. The young generally ride on the backs of parents when travelling far, in deep waters even though they are able to swim and even feed themselves when they are hatched.
After breeding, the swans lose all their flight feathers during moulting, so, they cannot fly for about a month. They stay in open water to avoid predators during such times. And if you are wondering what these birds eat to survive, it’s various types of weeds, algae and vegetation. The adult swans could be seen reaching under the water to eat water plants. Cygnets feed on bugs and other small invertebrates since they feed mostly on the surface of the water until they grow. These black swans could also be seen occasionally, grazing on pastures. Like all species of swans, the black swans too are monogannous; they choose partners for life and as researchers say the ‘divorce’ rate in this bird community stands at only six per cent, in contrast to that of humans. At present, naturalists claim that the current global population is around 500,000 individuals and there is no threat of extinction to this species. But going by the alarming rate other animal species are diminishing or disappearing due to global warming, poaching, hunting and loss of natural habitats, the fate of these birds too is in the balance. Let’s hope that these graceful birds will not suffer the same fate many of our other animal friends are facing today. Fact File* There are seven species of swans in the world. Except for the black swans of Australia and the black necked swans of South America, all the others are pure white. * A Dutch sailor named Antonie Caen is believed to have seen a black swan in the Shark Bay area in 1636. * A Dutch explorer, Willem de Vlamingh captured several black swans on the Swan River, Western Australia in 1697. (Many people didn’t believe him). * Black swans were scientifically described by Dr. John Latham in 1790 and accepted to be true only after that. * The black swan is very aggressive when defending its nest and eggs from intruders. * Cygnets are led to the water by the parents after 24 hrs of hatching. * The black swan is the state bird of Western Australia. * Swans as well as ducks and geese are members of the Antidae family in the order Anseriforues. * The black swan is New Zealand’s largest wetland bird. * Black swans breed either in pairs or in colonies. * About 5,000 birds are shot annually in New Zealand. * The black swan is the most social and least territorial of all swans. * The cygnets stay with the family unit for about nine months even though they have the ability to fly away by the time they are two months old. * The cygnets are greyish in colour and fluffy too. * The black swan has 22-25 vertebrae in its elongated neck. It is because of this that the bird can duck its head under the water to eat aquatic vegetation deep down. * The beaks have grooves that help in the feeding process. * They are good swimmers, but do not dive. * Black swans were introduced to New Zealand as a game bird and an ornamental water fowl way back in 1864. They also became popular as ornamental water birds in western Europe, especially in Britain. |
|
