Coscoroba Swan (Coscoroba coscoroba)

Coscoroba Swan

Subspecies

Monotypic species

Genus

Coscoroba swans are part of the order Anseriformes, in the family Anatidae (ducks, geese, swans). There are two genera in this family: Cygnus and Coscoroba. In the genus Coscoroba, there is just one species: C. coscoroba. Coscoroba swans live in the southern part of South America, in the countries of Chile, Argentina, Uruguay, southern Paraguay and southern Brazil. Southern populations migrate northward and spend the winter in northern Argentina, Uruguay and southeast Brazil. Those populations that live in the central part of their range likely remain sedentary. Externally, the body, head and legs appear to be more like a goose than a swan. As an example, their body is much smaller in comparison to other species of swans; the largest species average double the weight and have a wingspan at least 40% larger. Since they are smaller in size compared to other swan species, coscoroba swans require shorter distance to lift off from the ground or water. In contrast to other species of swan, coscoroba swans have a shorter neck and longer legs. Another feature that distinguishes coscoroba swans from other species is that feathers cover their facial skin, instead of bare skin extending from the bill to the eye. This species also lacks the characteristic basal knob found on all other five species of swans. Compared to other swans, the bill of a coscoroba swan is smaller and more resembles the bill of a duck.

Physical charateristics

Coscoroba Swans are more goose-like in appearance than their Northern Hemisphere relatives. Both sexes are all white, with black wingtips and red bills and legs. The Coscoroba Swan is one of only two all-white waterfowl in South America. The other all-white species, the male Kelp Goose Chloephaga hybrida, is much smaller, inhabits rocky coastlines, and lacks the red bill and legs of the Coscoroba Swan.

Listen to the sound of Coscoroba Swan

[audio:http://www.planetofbirds.com/MASTER/ANSERIFORMES/Anatidae/sounds/Coscoroba Swan.mp3]

Copyright remark: Most sounds derived from xeno-canto

wingspan min.:	150	cm	wingspan max.:	160	cm
size min.:	90	cm	size max.:	115	cm
incubation min.:	32	days	incubation max.:	37	days
fledging min.:	60	days	fledging max.:	75	days
broods:	1		eggs min.:	4
			eggs max.:	7

Range

South America : Southern Cone. The Coscoroba Swan is a South American species, living from Tierra del Fuego to C Chile and N Argentina. This species winters in South-eastern Brazil.

Habitat

They inhabit swamps, lakes, lagoons and other bodies of fresh water in southern South America.

Reproduction

Breeding season occurs in spring according to the range. The Coscoroba Swan mates for life, and usually nests solitary on small islands, in reedbeds or among tall grasses, always close to water.
The nest is a large mound of aquatic plants. The interior is lined with softer materials such as grasses and down. Female lays 4 to 7 eggs. Incubation lasts about 28 to 35 days by female alone, while the male protects the nest-site. The downy chicks are able to swim and feed themselves very soon after hatching. Adults defend them against predators and intruders.

Feeding habits

It feeds by dabbling or wading in the shallows, sometimes by grazing on waterside pasture, walking easily with its relatively long legs. Its longer legs no doubt help it take to the air with greater ease than other swans, as it does not patter during take-off. Generally shy and wary.

Video Coscoroba Swan

httpv://www.youtube.com/watch?v=T4Edcu5C4qQ

Conservation

This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). The population trend appears to be stable, and hence the species does not approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size may be moderately small to large, but it is not believed to approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.
Though its population was estimated at around 100,000 individuals, BirdLife International has listed the Coscoroba Swan as a species of Least Concern; habitat destruction and degradation through the diversion of wetlands are the chief threats to this species.

Migration

This species is a partial migrant, breeding in southern Chile and Argentina south to Tierra del Fuego, and then moving north in winter; the bulk of the population winters in central and northern Chile and Argentina and Uruguay, with individuals make it as far north southeastern Brazil. There is also a population on the Falkland Islands.

Distribution map

Coscoroba Swan distribution range map

Planet of Birds