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|Coscoroba Swan (Coscoroba coscoroba), Montevideo, Uruguay|
In nature the Coscoroba Swan (Coscoroba coscoroba) is only found in South America. Its distribution is very similar to that of the Black-necked Swan, with limits somewhat less extensive. During summer, the breeding season, it could be present from Chile (Chiloé) and the center of Argentina to Tierra del Fuego with some going as far south as the islands in the Beagle Channel. Most breed in southern Argentina and southern Chile. At this time of the year it is also present in the Falkland Islands where its numbers have increased but as of 1988 no nesting was documented.
Most of the population moves north before winter. In Chile they go as far as Santiago and east of the Andes they concentrate from Buenos Aires, Paraguay, Uruguay to southern Brazil (in Rio Grande do Sul). Some have made it to the center of Brazil.
There are some smaller groups in northern Uruguay, in the center of Chile and probably in other places which are sedentary. In these populations the pairs appear to maintain a territory which they defend all year.
Normally they are found at low elevations, although they are documented as high as 1000 meters. According to some Emails we have received, the Coscoroba Swan has been seen at quite higher elevations.
Considered fairly common within its distribution.
|Coscoroba Swan (Coscoroba coscoroba),|
|in a waterfowl collection in Miami, Florida, USA|
Shows preference for lakes and large ponds of fresh water, also seen on brackish water and in Brazil it is reported on the sea beaches. Can be found in water deposits not too deep and with not much current with high grass or other vegetation which offers protection; like the marshes and the swamps.
The Coscoroba Swan is relatively sociable within its own species and other waterfowl. It is seen in pairs and in groups, usually small with less than a hundred individuals, although when it congregates during the molt as many as two hundred have been seen. It is suspected that the groups are usually small because its population is not very abundant. In flight it has been seen with flamingos and during winter on the northern parts of its distribution it is not strange to see one or two in the groups of black-necked swans.
|Coscoroba Swan (Coscoroba coscoroba) in Maldonado, Uruguay|
It is estimated that once a pair bonds, they remain together for life, as is suspected with other swans.
Breeding season is during the southern (Austral) spring and summer. The pairs nest alone or in well spread out colonies. Each pair nest in an area or territory which they defend. If a pair nests early it is possible that a second clutch could be raised before the molt.
The nest could reach rather big proportions and is made on the ground in the tall grass close by the water. The building material is grass and other vegetable substances. In the center of the cup feathers and down are added.
The usual clutch is from four to nine eggs. The female takes care of incubation while the male stays close by and defends the territory. While incubating, the mother usually takes two daily beaks to go eating; before leaving the nest the eggs are covered. After about 35 days the eggs hatch. The cygnets have dark gray marks on their plumage, similar to the Whistling-Ducks. They fly from three to four months old.
|Coscoroba Swan (Coscoroba coscoroba)|
|checking out the bottom of the pond.|
|Montevideo, Uruguay. 1999.|
After nesting this swan moves to some lakes to molt. Normally this occurs during fall but there are indications that the ones at the southern end of its distribution molt earlier.
The diet consists of vegetable material and perhaps small animals. It feed by inserting the head, neck and sometimes a good part of the body underwater. Estimated to also feed on terrestrial plant seeds as the geese do.
Both sexes are alike. The average weight of males is bigger, but at simple sight it is practically impossible to tell the sexes apart.
The feathers are not all white. The primary, or flight feathers, are black as can be seen when the swans are swimming or during flight. In proportion, the wings are shorter and wider than other swans.
The beak is red and flattened. The facial skin is covered with feathers, not as in the other swans which is naked between the eyes and the beak. The legs range from pinkish to reddish. The neck, in proportion, is larger than in the geese but not as long as in the other swans.
They reach a length between 90 and 115 cm (about 3 to 4 feet).
wings average 480 mm;
average weight 4.6 Kg. (actual measurements from 3.8 to 5.4 Kg.)
bill from 63 to 68 mm,
tarsus from 92 to 94 mm,
wings from 427 to 458 mm,
average weight from 3.8 Kg. (actual measurements from 3.2 to 4.5 Kg.)
average weight day after hatching is 110 grams (99 to 119 grams).
average measurement of 89 X 61 mm (82 to 94 by from 53 to 67 mm)
average weight of 170 grams (129 to 203 grams).
|Coscoroba Swan (Coscoroba coscoroba)|
In captivity the average life span is about seven years, some reaching up to twenty years of age.
The name Coscoroba derives from the native people of the regions where this swan is natural. In reality it is an imitation of the sounds made by the swan, something like “cos-cor-o-ba”.
The Coscoroba Swan in Spanish is called “Coscoroba”, “Cisne Coscoroba”, “Ganso Coscoroba” and “Ganso Blanco”. In Portuguese: “coscoroba” and “capororoca”; in German: “Koskorobaschwan”; in French: “Cygne Coscoroba”.
|Coscoroba Swan (Coscoroba coscoroba). Maldonado, Uruguay.|
|Our thanks to|
|Gardens at Crandon Park Foundation, Miami, Florida, USA|
|for allowing us to take pictures in their gardens.|
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