Kingdoms / Animalia / Craniata / Aves / Anseriformes / Anatidae / Coscoroba / Species
< >  Coscoroba coscoroba - Coscoroba swan (Click photographs/illustrations: full picture & further details)
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INFORMATION AVAILABLE

GENERAL & REFERENCES

EXTERNAL APPEARANCES

REPRODUCTION

BEHAVIOUR

NATURAL DIET

RANGE & HABITAT

CONSERVATION

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General and References

Alternative Names (Synonyms)

Coscoroba blanc (French)
Cygne coscoroba (French)
Coscorobaschwan (German)
Koscorobaschwan (German)
Cisne coscoroba (Spanish)

Names for newly-hatched

Cygnet, Downy.

Names for non-breeding males or other colour-phases

 

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References

Species Author

Debra Bourne

Major References

B1, B3, B4, B8, B9, B19, B25, B26.

Aviculture references:
J23.13.w7
B7, B10.26.w2, B29, B30, B31, B40, B94, B95, B96, B97, B108, B128.w4
D1, D8

Other References

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TAXA Group (where information has been collated for an entire group on a modular basis)

Parent Group

Specific Needs Group referenced in Management Techniques

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Aviculture Information

Notes

General information:
  • Swans are generally aggressive and territorial, particularly while breeding, and each pair should be maintained in a separate pen, away from other swans, geese and large ducks, although the pen may be shared with small ducks, as these are usually ignored by most swan pairs. Fences adjoining other pens should be solid or screened with vegetation to avoid injury from swans trying to fight each other through wire fencing, and should be as tall as the swans themselves, to prevent fighting over the top of the fence.
  • Swans may be best kept on a large area of natural water containing aquatic vegetation, and the surrounding land. For a single pair, a pen of at least 400 square metres is suggested, of which half the area should be water and half grazing land. Banks should be at a shallow angle to allow easy entry to and exit from the water; this is particularly important if cygnets are to be parent reared. More than one pair may be kept in very large parks where each pair can establish a breeding territory. Swans appreciate water weed and grass, but other green foods such as lettuce and cabbage may be used as substitutes if necessary. They are relatively slow eaters and care should be taken in mixed enclosures that they get sufficient food. Natural food should be supplemented with extra green food, wheat and pellets; limited amounts of bread may also be given.
  • Good amounts of vegetation should be provided for nest building, with cover available for early-nesting species. Parent hatching and rearing is usual. Swans are able to defend their young against most predators, and their highly-aquatic lifestyle also makes cygnets less vulnerable. Unlimited green food should be available for the cygnets.
  • If hand-reared, cygnets should be kept in a brooder with a heat lamp (to give 92F in the first week), with sufficient room for the birds to choose their own comfort zone. Access to water for a swim is appreciated; this may be in an appropriately sized bowl initially (e.g. while the brooder is cleaned out). Starter pellets, chopped green food and for the first few days chopped hard-boiled egg may be given, and grit should be available. If weather permits the cygnets may be kept outside in a pen with a pond by two to three weeks old. It is important to ensure unlimited green food is always available and that the cygnets do start feeding initially (see: Stimulating Feeding of Downies (Waterfowl)), as there is a risk of Starveout.

(B7, B10.26.w2, B29, B30, B40, B94, B95, B97, B108, B128.w4, D1).

Species-specific information:

  • Coscoroba swans require large area of high-quality, preferably running, water and a good grazing area. Coscorobas are more delicate than most swans and natural and/or artificial shelter should be provided for protection in severe weather.
  • This species is less aggressive than most of the swans and they are not generally aggressive outside the breeding season, but they are usually more aggressive and territorial during nesting season (some individuals are more aggressive than others). It may be possible to keep more than one pair in a large enclosure (e.g. three pairs reported to be kept successfully in a one hectare enclosure); in smaller enclosures they may or may not tolerate other species, depending on the temperament of individual birds. In addition to available grazing they may be fed grain and waterfowl pellets, plus fresh plant material year-round e.g. lettuce, duckweed, winter greens, scraped carrots), and bread.
  • Coscorobas are bred sporadically rather than easily, but established pairs usually continue breeding once they have started. Eggs are laid on a large pile of vegetation, laying usually occurring from early April to the end of May. They frequently lay a second clutch if the first clutch is removed or if the cygnets are removed soon after hatching; they may lay a third clutch particularly if they are not allowed to incubate their previous clutches. Cygnets may be parent incubated and hatched, or parent incubated until just before hatching then hatched in an incubator and hand-reared. These swans are not always good sitters - artificial incubation and hand rearing may be required; they may also be broody hatched and reared. Cygnets are easy to rear on commercial diet plus green food and grated hard-boiled egg. Whether broody or hand reared, fresh clean turf and protection from draughts and rain should be provided.
  • Coscoroba swans do not appear to hybridise.

(J23.13.w7, B29, B30, B31, B40, B95, B96, B97).

Aviornis UK Ringing Scheme recommended average closed ring size: T 20.0mm (D8).

Management Techniques

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External Appearance (Morphology)

Measurement & Weight

Length 35-45 inches, 90-115cm (B3, B1)
Adult weight General 3.2-5.4kg (B1)
Male 3.-5.5kg, average 4.6kg (B3)
Female 3.2-4.5kg, average 3.8kg (B3)
Newly-hatched weight 109g (B9)
Growth rate Take eight months to reach adult size.

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Head

Adult Bill Male Bright red-pink, flattened duck-like shape.
Variations (If present) --
Eyes (Iris) Male Brown.
Variations(If present) --
Juvenile Bill Greyish
Eyes (Iris) Brown.

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Legs

Adult Male Pink.
Variations (If present) --
Juvenile Blue-grey.

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Plumage

Adult Male White with black wing-tips (distal part of primary feathers only).
Variations (If present) --
Juvenile White with brownish pattern on head and upperparts.

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Newly-hatched Characteristics

General: Upperparts silver-grey with three darker bands along body and dark crown to head. Underparts white.
Bill: Grey with pink tip and near gape.
Feet: Pale pink with grey tinge.

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Reproduction

Reproductive Season

Time of year In local spring, generally July to October, later further south. Lay as early as late February or March in Britain.
No. of Clutches --

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Nest placement and structure

On small islands, in reedbeds or long grass near water, a large mound of vegetation lined with soft grass and down.

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Egg clutches

No. of Eggs Average --
Range 4-7 (B1); 3-9 (B8)
Egg Description Whitish cream. Size: 91 x 63mm, weight: 185g

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Incubation

About 35 days (B1); 33-35 days (B8)

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Hatching

Synchronous.

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Fledging

120 days (B1, B8).

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Sexual Maturity

Males Two to three years old.
Females Two to three years old.

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Behaviour

Feeding Behaviour

Adults Forage in shallow water and also graze along the water's edge.
Newly-hatched --

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Parental Behaviour

Nest-building By the male.
Incubation By the female.
Newly-hatched Tended by both parents.
Juveniles

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Social Behaviour

Intra-specific Found in flocks, usually less than 100 birds, outside the breeding season. Territorial while breeding.
Inter-specific --

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Sexual Behaviour

Strong, permanent pair bonds.

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Predation in Wild

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Activity Patterns

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Circadian --

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Natural Diet

Adults

Varied diet: plants, aquatic invertebrates, fish spawn.

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Newly-hatched

Similar to adults.

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Range and Habitat

Distribution and Movement (Migration etc.)

Normal Southern South America from central Chile and northern Argentina south to Tierra del Fuego. Winters in north to central Chile, north-central Argentina and reaching south-east Brazil (Tropic of Capricorn).
Occasional and Accidental

Falkland Islands.

Introduced

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Habitat

Lakes, lagoons and freshwater swamps with good vegetation on the edges.

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Conservation

Intraspecific variation

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Conservation Status

Wild Population -
(Importance)

Not considered globally threatened. Widespread in Argentina, decreasing markedly in some areas such as Chile. Generally patchy distribution, locally common (B1, B8).

CITES listing CITES II (B1)
Red-data book listing --
Threats Loss of temperate marshes (B1).

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Captive Populations

Reasonably common, but not abundant. Relatively few collections breed this species regularly (B8)

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Trade

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