Black Swans (Cygnus atratus) are native to Australia and are an iconic species. They are so revered that they serve as the official emblem of Western Australia, appearing on the state flag and coat of arms. In fact, you can find their image on stamps, sports uniforms and even public buildings around Western Australia (WA). The Swan River in Perth was named after this beautiful bird when the British established the Swan River Colony in 1829. In addition, Black Swans have also been introduced to New Zealand.

Description

The male black swan, also known as ‘cobs’, can grow up to 110 to 142 centimetres in length and weigh between 3.7 to 9 kilograms. They have a wingspan of 1.6 to 2 meters and a unique “S”-shaped curving neck, which is the longest among other swan species. Male swans also have a longer and straighter bill than females, also known as ‘Pens’, and are slightly larger. These large birds have predominantly black plumage, broad white wingtips when in flight, and a vibrant red bill. They require a clearance of forty meters to take off and can reach flying speeds of up to 80 km/h. Black swans have a lifespan of 40 years. Immature swans are known as Cygnets, which have greyish-brown feathers with pale edges.

Black Swans are nomadic, with erratic migration patterns that depend on climatic conditions. Their migration follows no set route or pattern but is in response to drought or rainfall, always hunting for wet areas. Outside of the breeding season, they can travel vast distances, flying mostly at night.

Habitat

Their preferred habitat is the fresh, brackish and saltwater of lakes, swamps and rivers with the underwater vegetation they need for food and nesting materials. They prefer permanent wetlands, including ornamental lakes. However, they can also be found in flooded pastures, tidal mudflats and ornamental lakes.

Diet

Black Swans are vegetarians. They consume algae and weeds, which they obtain by plunging their long necks into the water at depths up to 1 metre deep. While they will also occasionally graze on land, they are ungainly walkers.

Breeding

Black Swans are mostly monogamous breeders. While older swans generally mate for life with one partner, younger swans are known to pair up for a short time, breed and then desert the nest. Thus, leaving the partner (of either sex) to care for the young. Breeding occurs mainly from February to May in the north and May to September in the south.

Near the water, the female swan constructs a nest using sticks, dead leaves, and debris. She lays one egg each day, which usually amounts to five or six eggs, but can sometimes reach nine. Despite the varying laying times, the parents only sit on the eggs and do not warm them, ensuring that all the eggs hatch together. Incubation lasts between 35 to 48 days, and both parents share the duty. After the breeding season, the adult swan goes through a moulting period during which it sheds its feathers and is unable to fly.

The babies, known as cygnets, are able to fly at six months. However, they often remain with the family for up to nine months. They reach sexual maturity between 18 and 36 months of age.

Predators

Black swans and fledglings are at risk from ravens, eagles, hawks and rats. However, the species is not endangered and are protected under the Australian National Parks and Wildlife Acts (1979). They are listed as Least Concern on the IUCN Red List of Threatened Species.