Black Swan

## Description

The black swan (Cygnus atratus ) is a large waterbird, a species of swan which breeds mainly in the southeast and southwest regions of Australia. Within Australia, the black swan is nomadic, with erratic migration patterns dependent upon climatic conditions. It is a large bird with mostly black plumage and a red bill. It is a monogamous breeder, with both partners sharing incubation and cygnet-rearing duties.

The black swan was introduced to various countries as an ornamental bird in the 1800s, but has managed to escape and form stable populations. Described scientifically by English naturalist John Latham in 1790, the black swan was formerly placed into a monotypic genus, Chenopis. Black swans can be found singly, or in loose companies numbering into the hundreds or even thousands. It is a popular bird in zoological gardens and bird collections, and escapees are sometimes seen outside their natural range.

This bird is a regional symbol of both Western Australia, where it is native, and the English town of Dawlish, where it is an introduced species.

## Appearance

One of only three swan species that inhabit the southern hemisphere, the large Black swan is an unmistakable water bird. The body of an adult Black swan is mostly black, except for its broad white wing tips, visible in flight. Its bill is bright red, having a pale tip and bar, and its feet and legs are grayish-black. Its neck is long (the longest neck amongst swans, relative to its size) and it is curved into an "S"-shape. The males are slightly bigger than the females and have a longer and straighter beaks. Juvenile Black swans are grayish-brown with lighter-edged feathers.

## Distribution

Black swans are natives of Australia, including Tasmania, and mainly occur in Australia's south-eastern and south-western wetlands. These birds were once thought to be sedentary, but are now known to be highly nomadic. There is no set migratory pattern, but rather opportunistic responses to either rainfall or drought. Black swans inhabit rivers, lakes, and swampland in water that is fresh, salt, or brackish. They prefer habitats that have aquatic vegetation but sometimes live in terrestrial areas like flooded fields or dry pastures when food is scarce.

## Behavior

Black swans are active during the day and feed in a similar manner to other swans. When feeding in shallow water they will dip their heads and necks under the water and they are able to keep their heads flat against the bottom while keeping their bodies horizontal. In deeper water swans up-end to reach lower. Black swans are also able to filter feed at the water's surface. These beautiful birds may be found on their own but they also often form loose groups consisting of several hundred or sometimes thousands of birds. They usually move in flocks, sometimes nest in colonies, and are the least territorial of swan species. They are strong fliers, traveling together in a line or V shape, beating their wings slowly, and making whistling noises. On the water as well as in flight, Black swans make a range of high-pitched, musical, bugling, baying, or trumpeting calls. They have also been heard to make a variety of softer crooning notes. If disturbed while nesting they usually make a whistling sound.

## Diet

Black swans are herbivores (folivores), feeding on vegetation both in the water or in pastures, or when on farmland. Common aquatic plants they feed on include algae, leaf of reedmace, and stoneworts. Occasionally they will eat insects.

## Reproduction

Black swans are monogamous and often have the same mate for life. They are territorial and remain in solitary pairs during mating but occasionally mate in colonies. February through September is the breeding season. Usually, the female swan makes a nest from sticks, debris, and dead leaves into a mound floating on the water. She lays 5 to 6 eggs, one day apart. Incubation starts once all the eggs are laid and lasts 35 to 48 days. Males help with incubation. The cygnets are precocial and can swim and feed soon after hatching; however, they are brooded in the nest after hatching for a period of 2 to 3 weeks. They fledge between 150 to 170 days old. Black swans can fly at about 6 months old and stay with their family group for about 9 months. They reach reproductive maturity within 18 to 36 months.

## Population

### Population threats

There are no major threats to Black swans, although brief hunting seasons have been instigated in some parts of their range due to crop damage caused by this bird.

### Population number

According to Wikipedia, the current global population of the Black swan is estimated to be around 100,000-1,000,000 individuals, while the population in Japan has been estimated at around 100-10,000 introduced breeding pairs. Currently, this species is classified as Least Concern (LC) on the IUCN Red List and its numbers today are stable.

### Ecological niche

Black swans are important in their ecosystem, as they affect species populations that they consume, and as a food source for their natural predators.

## Fun Facts for Kids

The meaning of the Black swan's scientific name is a swan attired in black, this referring to its almost entirely black plumage.

A big group of Black swans on the ground is called a bank, but when in flight the group is called a wedge.

The Black swan swims with only one leg, tucking up the other above its tail. This may be because the swan can change direction more easily when swimming if it needs to escape from a predator or move quickly to get to the food.

A Black swan has the longest neck, relative to its size of all swan species.

A Black swan is the official bird of Western Australia and is featured on the flag of this state and in its coat of arms.

Before European explorers reached Australia, it was thought that only white swans existed. Antounie Caen, a Dutch mariner, was the first European to see the incredible sight of Australian Black swans in 1636 in Shark Bay.