Black-necked Swan

Black-necked Swan

The black-necked swan is scientifically named Cygnus, meaning swan, and melancoryphus, meaning black pigment. It listed as the largest South American water-fowl. The black-necked swan is the least populated member of the Cygnus genus.

It breeds in Chilean Southern Zone, Patagonia, Tierra del Fuego and on the Falkland Islands. In the southern winter, this species changes its location and move up north towards Paraguay, Bolivia and southern Brazil.

It is a short-winged bird, but that does little to the speed of its flight. It has an average lifespan of 10 years, though it can live up to 30 years. A group of swans can be called a bevy, bank, herd, wedge or flight.

Table of Contents

Scientific Classification

SpeciesC. melancoryphus


The black-necked swan has white plumage, a black head, a black neck and a grey bill with a red knob at the base.

These red knobs get larger in males during the breeding season. Behind the eyes, there are white stripes. The male swan is a bit bigger than the female.

Its young one has a light-greyish plumage with black feet and bill. Similar to it’s closest relatives, the mute and black swan, it is somewhat quiet.

Although, one trait that stands them out from other wild water-fowls is that both the male and female swan often carry their offspring on their back.

The males are called cobs while the females are called pens. The black-necked swan has up to 24 or 25 vertebrae which are huge for a mammal as most mammals have just seven.

Among flight birds, the black-necked swan also has the largest size of eggs.


They are very social animals, and they are very outgoing when it’s not their breeding period. The swans tend to get extremely territorial during their breeding period.

They split up into mating pairs and take up nests in small groups of pairs or just as a pair.

They reunite once their eggs have hatched with each group numbering up to thousands of birds. Depending on the weather and resources available, they are likely to move around.

They are day creatures and spend most of their time on the water. The males defend their territory by the display of ferocious behaviour such as pushing their head forward and bringing the head down.

They fight with their wings, and when they are done, they return to the female in victory with a recurring chin lift and calling.

Black-necked swans that are raising their young ones can get very protective. They carry them on their back while swimming. Sometimes, the cobs violently vie for a mating partner.

They do this in something called a triumph ceremony. They challenge a rival suitor, and then the winner returns to his prospective mate to perform an intricate ceremony. They are wary of humans and produce a soft, almost musical sound while flying.


  • Body length: 102 – 124 centimetres
  • Weight: 4 – 5.4 kilograms
  • Wing length: 135 – 177 centimetres


They live in swamps, freshwater marshes, brackish lagoons and shallow lakes in the southern region of South America.

The Great Chilean earthquake created wetlands such as the Anwandter Nature Sanctuary in Cruces River. These wetlands have become a popular spot for the black-necked swan.


The black-necked swans are herbivores. They primarily feed on aquatic vegetation, but they also feed on fish eggs and insects.

Their primary diet of aquatic plants plays a crucial role in their population control and prevents these plants from becoming invasive species


The young ones of the black-necked swan are called cygnets or flappers. The swan attains sexual maturity two years after birth.

The pens (female swan) can lay up to 4-6 eggs at a time and the incubation period lasts within 34-36 days.

They give birth to their offsprings on a nest bedded with vegetation.  They attain independence when they reach the tender age bracket of 8 – 14 months.

The swans are monogamous in their mating, meaning they mate with one partner for life. Each pair of swans court each other by facing each other with shaking wings and nodding their heads.


In the year 2004 and 2005, black-necked swans from the Anwandter Nature Sanctuary died or moved away in their thousands. This was due to contamination by the Valdivia Pulp Mill situated on the Cruces River, which flows to the wetlands.

In 2005, nearly all the swans were killed with just four birds left from a previous population of about 5,000. The cause of death was examined and discovered to be the high level of metallic content in the water, particularly iron.

Today, the swans are widely dispersed across various countries, and it is now a usual sight throughout the wetlands. The black-necked swan’s conservation status is pegged as Least Concern on the IUCN Red List of Threatened Species.

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