DISTRIBUTION:

The Black-necked Swan (Cygnus melancoryphus) is natural to South America. Its distribution extends from southern Brazil to Tierra del Fuego.

During spring and summer (northern hemisphere fall and winter) it breeds in Chile (from Huasco), Paraguay, Argentina and Uruguay. It also breeds in the Falkland Islands. During this season some go down as far as the Beagle Channel Islands, south of Isla Grande in Tierra del Fuego, and west to the archipelago of Juan Fernández.

As winter approaches these swans move north, becoming abundant in Paraguay and some are seen in Brazil in Rio Grande do Sul, Santa Catarina and Paraná, some even reaching São Paulo; in the past has been seen in Rio de Janeiro.

ELEVATION:

Documented up to 1200 meters above sea level.

MOVEMENTS:

Some populations are migratory, others are sedentary. Not much is known about the actual movements from the cold regions to the warmer zones and back.

STATUS:

Fairly common within its distribution.

FLIGHT:

The flight is strong and capable of long journeys. Certain difficulties taking off and landing.

HABITAT:

Shows preference for freshwater lakes and ponds, also seen in brackish water and the sea. Frequent on the marshes and deposits of water with algae. Some of these swans have been seen swimming in a line in the sea near the coast of Brazil during winter.

BEHAVIOR:

The Black-necked Swan is considered the most aquatic of all the swans. Although it is capable of walking with slight difficulty, it spends most of the time in the water.

They are sociable when not breeding. After the breeding season they congregate counting in the thousands.

REPRODUCTION:

The southern hemisphere spring starts the nesting season. The populations to the south, which are among the ones starting somewhat later in the season, are already breeding in August. Normally one clutch per year, although some could raise two if they start early.

This swan nests in colonies well spread out or solitary. There is documentation of some nesting not too far from each other.

The nest is made in the grass next to lakes, and in small islands. The clutch count normally is from three to seven cream eggs. The female takes care of the incubation, which lasts from 34 to 36 days. The male stays nearby and protects the nest, attacking any animal that comes near the nest area. He also protects the cygnets with the same determination.

The cygnets are born white, the beak and legs are dark gray. Later this plumage will be replaced by one that is very light gray. The neck starts darkening when they are the size of their parents. At one year of age adult plumage is obtained. The red thickening on top of the beak do not develop until the third or fourth year.

As some of the other swans and some water birds, when the cygnets are small rather than swim they climb on the parents back. They hide below a parent wing and show their head once in a while.

FOOD:

This swan feeds on algae and aquatic plants. Possible also that it eats small invertebrates it catches in the water.

DESCRIPTION:

Both sexes have the same appearance. Males are slightly bigger and the red thickening (or knob) over the base of the beak usually grows larger on males. Except for the Coscoroba, this is the smallest swan.

Once they are adult, the feathers on the head and neck are black, except for a white line on each side of the head that goes from the beak to the eye, continuing to the back of the head (please see picture on the Taxonomy page). The rest of the plumage is white. The facial skin is red as is the thickening on top of the beak. Legs are pinkish.

Some figures:
In length they reach from 102 to 124 cm (40 to 49 inches).
Males:
   bill from 82 to 86 mm.,
   tarsus from 85 to 88 mm.,
   wing from 435 to 450 mm.,
   weight from 4.5 to 6.7 Kg. (about 10 to 15 pounds)
Females:
   bill from 71 to 73 mm.,
   tarsus from 78 to 80 mm.,
   wing from 400 to 415 mm.,
   weight from 3.5 to 4.4 Kg. (about 8 to 10 pounds)
Cygnets:
   average weight day after hatching is 150 grams (129 to 184 grams).
Eggs:
   average size is 101 X 66 mm (93 to 109 by from 63 to 69.3 mm)
   average weight of 247 grams (173 to 274 grams).

MOLT:

They molt the feathers once a year; at the end of the breeding season and before moving north. In Argentina the molt takes place from November to February.

LIFE SPAN:

In captivity it has an estimated life span of about seven years; some have made it to be twenty years old.

OTHER NAMES:

The Black-necked Swan in Spanish is called “Cisne de Cuello Negro”; in Portuguese: "cisne-de-pescoço-preto".