The Dutch navigator Willem de Vlamingh was one of the first Europeans to see Black Swans as he sailed up and named the Swan River. In 1697, his expedition took three swans to Batavia (Indonesia) with them, but the birds died(4). An exploratory party led by Captain James Stirling marvelled at the spectacle of Black Swans rising from the water as their boats navigated the Swan River in 1827. While admired for their beauty, swans were also a popular food resource for early settlers(4). Today, the once abundant Black Swans are now far less common on the river system.
The birds are entirely black except for the white outer flight feathers of the wings, with an orange to dark red beak. The white eye becomes red during breeding season. The cygnets (chicks) are covered with light grey down. Males grow about 1.3 metres long and females grow to 1.2 metres. Females also have slightly shorter necks than males(1). Black Swans have a trumpet-like call.
Black Swans predominantly occur in the southeast and southwest of Australia, live throughout southern Australia, extending south to Tasmania and north to Townsville in Queensland and Port Headland in Western Australia(1). They have been introduced to New Zealand.
Black Swans frequent lakes, rivers, estuaries and swamps. In the Swan Canning Riverpark, Black Swans are most commonly found in areas of shallow, vegetated foreshore and are also found in close proximity to seagrass meadows in the lower estuary(3). They live freely in ornamental lakes and ponds in cityscapes(2). For nesting, water levels, materials for building nests, proximity to feeding areas and freshwater (for young) are essential(4). Swans in the Swan Canning Riverpark show a preference for sheltered, vegetated sites with little or no access by dogs(3).
Breeding may occur throughout the year but is often limited to February-May in the north and May-September in the south. Black Swans are ready to breed at 18 months of age and most breed before their third year(1). While older birds generally bond permanently with one partner, younger birds may pair up for only a short time, breed then desert the nest, leaving the other partner of either sex to care for the young(1). After leaving, the deserter will often mate again and females may produce up to four broods in one year. Nests are constructed of mounds of vegetation on reeds, islands or in tall bushes near water(1). Usually five to six eggs are laid but there can be as many as nine. Eggs are pale green or dullish green-white, and slightly lustrous(2). Black Swans moult every year after breeding season and are unable to fly during this period. They often gather on open lakes in large numbers.
Black Swans primarily feed on submerged aquatic vegetation, but will also consume invertebrates associated with it(2). They can also graze pasture close to water(1).
Loss of habitat has significantly impacted Black Swans in the Swan Canning Riverpark. As the city has grown large areas of shoreline habitat have been filled or degraded. In areas where vegetation has been retained, disturbance is an ongoing issue.
The practice of feeding bread and other food scraps does these birds more harm than good. Swans may become dependent on humans to feed them and lose their natural instincts to forage for food. Adult birds may fail to teach juveniles how to find natural foods. Birds that are conditioned to being fed by humans have a decreased wariness of predators and this potentially makes them more vulnerable to dogs, cats and foxes.
Black Swans 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.
1. Readers Digest (1988). Complete Bood of Australian Birds. 2nd Edition. Readers Digest, Sydney.
2. Cayley, N.W. (1984). What Bird is That? 2nd Edition. Angus and Robertson. NSW.
3. McMahon, K., Lavery, P. Barwick, H and Alport, W. (2007). Black Swan (Cygnus atratus) habitat use in the Lower Swan River estuary. Report to the Ernest Hodgkin Trust for Estuary Education and Research. Edith Cowan University, Coastal Marin Ecosystems Research Group.
4. Brearley, A. (2005). Ernest Hodgkin’s Swanland: Estuaries and Coastal Lagoons of South-Western Australia. UWA Press, Perth.
Image by Jennifer Sumpton