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General and References

Alternative Names (Synonyms)

Cisne mudo (Spanish)
Cisne Vulgar (Spanish)
Cygne muet (French)
Cygne tuberculé (French)
Höckerschwan (German)
Knobbelzwan (Dutch)
Knölsvan (Swedish)
Polish Swan
White Swan
Cygnus immutabilis - Polish swan

Names for newly-hatched

Cygnet, downy.

Names for non-breeding males or other colour-phases


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Species Author

Debra Bourne

Major References

B1, B2, B3, B4, B8, B9, B19, B25, B26, B27.

Other references:
B38, B138

Aviculture references:
B7, B10.26.w2, B29, B30, B31, B40, B94, B95, B97, B108, B128.w4, B129, B139
D1, D8

(UK Contacts)

(Further Reading)
Click image for full contents list of ELECTRONIC LIBRARY

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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


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 92°F 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

  • Mute swans are easily kept on large areas such as park lakes etc. as well as on water areas in zoos or bird collections. Territorial and aggressive, particularly while breeding (nesting or with young cygnets), when they may seriously attack humans as well as intruding waterfowl and even last-year's offspring if they attempt to stay in the area, this species requires a separate enclosure. Care should be taken in re-pairing after the loss of one swan, as a new female may initially be attacked by the male. They require a good water area.
  • These swans are easy to breed, nesting on a large pile of vegetation, on an island if available; a large amount of vegetation should be provided for nest building. They usually lay eggs from March to June and may re-clutch if the first brood is unsuccessful. They require regular supplementary feed while rearing cygnets, unless on large lakes with ample natural food available. Juveniles are driven away in winter or spring, before the next breeding season and will have to be removed if they are pinioned.
  • Starter crumbs should be supplemented with plentiful green food and changed to lower protein grower diet by three weeks old. Constant access to water for swimming assists in avoiding the development of leg problems.
  • Hybridisation is not common, but has been reported with all the other Cygnus spp. (Cygnus buccinator - Trumpeter swan, Cygnus columbianus - Tundra swan, Cygnus cygnus - Whooper swan, Cygnus atratus - Black swan, Cygnus melanocorypha - Black-necked swan); also with Branta canadensis - Canada goose and several Anser spp.: Anser anser - Greylag goose, Anser cygnoides - Swan goose, Anser caerulescens - Snow goose.

(J23.13.w7, B29, B30, B31, B97, B129, B139, D1)

Aviornis UK Ringing Scheme recommended average closed ring size: W 27.0mm (D8).

Individual Techniques linked in Wildpro

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External Appearance (Morphology)

Measurement & Weight

Length 50-61", 125-155cm (B3); 125-160cm (B1); 145-160cm (B2).
Adult weight General 6.6kg-15.0kg (B1).
Male 8.4-15.0kg, average 12.2kg (B3); mean 26.8 lbs. (B8).
Female 6.6-12.0kg, average 8.9kg (B3); mean 19.6 lbs. (B8).
Newly-hatched weight Average 211-220g (B9).
Growth rate 34.1 times hatching weight at 160 days (B9.5.w6).

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Adult Bill Male Orange-pink with black edging, nail and around nostrils. Knob over bill.
Variations (If present) Female: Bill knob smaller.
Eyes (Iris) Male Brown.
Variations (If present) --
Juvenile Bill Grey.
Eyes (Iris) Brown.

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Adult Male Black.
Variations (If present) Pinkish-grey in ‘Polish’ leucistic colour phase.
Juvenile Black.

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Adult Male White
Variations (If present) --
Juvenile Greyish brown plumage, begins to turn white during first winter but some grey feathers remaining to second winter.

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Newly-hatched Characteristics

General: Upperparts pale grey (white in 'polish' (leucistic) cygnets; underparts white.
Bill: Dark blue-grey.
Feet: Blue-grey; pale grey-pink in 'Polish' leucistic form.

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Reproductive Season

Time of year Spring; earliest eggs mid-March in Britain.
No. of Clutches Sometimes lay a second clutch if the eggs or young cygnets are lost.

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Nest placement and structure

Substantial nest of surrounding vegetation built near water, on islets or in shallow water. Lined with soft grass and a little down.

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Egg clutches

No. of Eggs Average 5-7 (B1); 4-6 (B8)
Range 3-12 (B1); 1-11 (B8)
Egg Description Grey, green-white or pale blue-green (B3, B8). Size: 115 x 75mm, weight: 340g (B3).

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35-36 days (B1, B3); 35-38 days (B8).

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Synchronous, within 26 hours.

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120-150 days (B1, B8).

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Sexual Maturity

Males Occasionally breed at three years old, more often at four years old.
Females Occasionally breed at two years old, more often at three years old.

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Feeding Behaviour

Adults Aquatic vegetation up to 1m depth by dipping head and neck or upending (mainly in deeper water >45cm). Also feed on land, for example on pastures and cereals.
Newly-hatched Cygnets consume vegetation torn off by their parents.

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Parental Behaviour

Nest-building Usually isolated nests in defended territories. Built by both sexes, the male passing material to the female.
Incubation Mainly by the female, but the male sits while the female is feeding, and may take over if she is killed.
Newly-hatched Both parents raise the youngsters; the female broods young cygnets, which often ride on their parents' backs, particularly in the first few weeks and more often on female than male.

Driven off in autumn when plumage whitens or stay with parents until following spring.

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Social Behaviour

Intra-specific Breeding pairs are usually highly territorial, but a few places where they have been semi-domesticated in the past, hold colonies, for example at Abbotsbury in Dorset (Britain), also in Poland and Denmark.

Non-breeders and immature birds are gregarious throughout the year. Unsuccessful pairs may leave territory and join flocks prior to the moult.

Leucistic 'Polish' juveniles, being white, are sometimes attacked by their parents.

Inter-specific Aggressive particularly to large white birds while breeding. Generally more tolerant of smaller ducks but sometimes kill (by drowning) ducklings and downy chicks of coots and moorhens.

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Sexual Behaviour

Strong, permanent pair bonds.

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Predation in Wild

Foxes, crows and pike.

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Activity Patterns

Predominantly aquatic.
Circadian Mainly daylight feeders.

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Natural Diet


Mostly leafy parts of aquatic vegetation, also grain. Small quantities of grass, aquatic invertebrates and amphibians.

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Vegetation, also insects and aquatic invertebrates.

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Range and Habitat

Distribution and Movement (Migration etc.)


From Britain and Ireland patchily through north Europe and central Asia to eastern China.

Varies from wholly sedentary through partially migrant to wholly migratory, depending on area: swans from coldest areas move south for winter. In sedentary areas may remain on breeding territories or join winter flocks. Sometimes move for moulting period.

In London: a common resident breeding species in the London Area, with more than 100 known nests including some in Inner London; groups of several dozen may be seen on the Thames. (J322.65.w1)

Occasional and Accidental

South to Spain, Hungary, Iraq, Jordan, Egypt, Cyprus, Malta, Azores and Pakistan.


America (USA, Canada), Japan, South Africa, SW Australia, New Zealand, Faeroes (B38).

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Large open lakes with good vegetation (floating, emergent and bottom) and extensive shallow areas, shallow marshes, slow-moving rivers, estuaries, sheltered coasts etc. In Western Europe and areas where introduced, adapted to close association with human habitats, uses gravel pits, park lakes, canals, rivers, reservoirs etc.

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Intraspecific variation


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Conservation Status

Wild Population -

Not threatened. Range increasing due to introduced populations (B1, B8, B38).

CITES listing --
Red-data book listing --
Threats Lead poisoning and power lines are notable causes of death and can have substantial effects on populations (B8).

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Captive Populations

Common, easy to keep and breed (B8).

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