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Cygnus atratus
Habitat: Black swans live in lakes, rivers and swampland, which can be fresh, salt or brackish water. They prefer habitats with aquatic vegetation. While their natural habitat is aquatic they are sometimes found in terrestrial areas such as dry pastures or flooded fields when food is scarce.
Diet: Black Swans eats sub-aquatic foliage that it can reach under water using its long neck. It is herbivorous, eating vegetation and plants either in the water or on land in pastures or on farm land. Occasionally they also eat insects.
Reproduction: Black swans are monogamous and often have the same mate for life. They are territorial and stay in solitary pairs when mating but are known to occasionally mate in colonies. One particularly interesting thing about the courting behavior of black swans is the "Triumph Ceremony". It is used to strengthen pair-bonds between mates, between parents and cygnets (baby swans), and for threatening territorial displays. The male swan approaches the female swan with wings and chin lifted, calling repeatedly. Then the female returns the same call. They then dip their heads alternating with erect postures. After this the birds call with their necks outstretched and bills pointed upward; then they hold their necks at a forty five degree angle and point their bills downward and at a right angle, they proceed to swim in a circle.
The breeding season is from February through September. Usually the female (occasionally the male) makes a nest of sticks, dead leaves and debris into a floating mound on top of the water. Each female may lay between 5 to 6 eggs, the eggs are laid one day apart. There is a 35 to 48 day incubation period which begins when all the eggs have been laid. Males are known to help with incubation. Chicks are precocial but are brooded on the nest for 2 to 3 weeks after hatching. They fledge from 150 to 170 days after hatching. They remain in family groups for about 9 months and are able to fly at around 6 months old. The chicks are sexually mature in 18 to 36 months. Young black swans join juvenile flocks for one to two years before they begin breeding.
Both male and female black swans incubate the eggs. Chicks are precocial and can swim and feed soon after hatching. They may ride on their parents' backs when they venture into deep water. The chicks can fly in 2 months, but they remain in the family group until the next breeding season. Juvenile black swans often form flocks until they find a mate.
Physical description: Swans are the largest of all waterfowl. Black swans' closest relatives are mute swans. Black Swans have the classical swan look with a long arched neck and raised eyebrows. As the name implies they are mostly black. Some of the wing feathers are white. They also have reddish or pinkish irises and richly colored red bills with a white line. When they are fully grown they have a length of 110 to 140 cm and weigh between 3700 to 8750 g. The wingspan ranges between 160 to 200 cm.
Behavior: Black swans tend to move in flocks; they are the least territorial of all swans and sometimes nest in colonies. They are nomadic when food is scarce but are otherwise sedentary. They feed at dusk and travel at night, calling as they fly.
The threatening behavior of black swans is similar to mute swans; they both flap and wave their wings with two or three strokes followed by a call. However, the wings of black swans make a louder sound than mute swans. Also the standing stance is different; black swans hold their necks erect with a downward point of the bill and ruffled feathers.
Status: Common
Fun Facts:
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Black swans use calls and visual signals to communicate. |
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They have advertisement calls used in territorial defense and specific calls used in Triumph Ceremonies. They have a high pitched, weak voice. |
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They also use visual displays to communicate such as raising their shoulders or flapping their wings to threaten predators or other swans in their territory. |
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