Kingdoms / Animalia / Craniata / Aves / Anseriformes / Anatidae / Clangula / Species
< > Clangula hyemalis - Long-tailed duck (Click photographs/illustrations: full picture & further details)
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General and References

Alternative Names (Synonyms)

Eisente (German)
Harelde boréale (French)
Canard nequelon (French)
Harelde de Miquelon (French)
Pato havelda (Spanish)
Pato de cola largo (Spanish)
Havelda (Spanish)
IJseend (Dutch)
Alfägel (Swedish)
Harelda glacialis

Names for newly-hatched

Duckling, downy.

Names for non-breeding males or other colour-phases


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Species Author

Debra Bourne

Major References

B1, B2, B3, B6, B8, B19, B25, B26, B27.

Other references:

Aviculture references:
Seaduck general: B7, B29, B40, B94, B129, D1
Species-specific: B29, B30
D1, V.w10

(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:
  • Seaducks are generally winter-hardy and sociable. They are preferably kept on a large area of clean, cold, deep water, at least some of which (preferably half the area) should be more than 60cm and preferably more than1m deep. As with other diving ducks, most species are relatively ungainly on land and ponds should have shallow sloping banks. Some cover along the pond edges will generally be appreciated. Preferred nesting sites vary greatly within this group, from open ground nesting to thick vegetation and tree holes.
  • Diets of grain, pellets fish and seafood may be used, also bread. These ducks generally need a higher-protein diet than most waterfowl species and high-protein pelleted diets specifically designed for seaducks are now available, although supplementation with fish may still be important particularly for breeding.
  • Feeding in troughs containing stones may avoid the development of overgrown bills. Provision of salt water may decrease the incidence of fungal and other infections.
  • Ducklings may be given high-protein starter crumbs and live food, and provided with access to deep water for swimming from an early age.

(B7, B29, B40, B94, B129, D1)

Species-specific information:

  • Long-tailed ducks require clean, fresh, deep water, with at least 50% of the area greater than 80cm minimum, preferably one metre. Waterfowl breeders pellets plus high-protein dehydrated insectivorous food and trout pellets have been use for feeding in the past. Pellets designed for seaducks are now available.
  • These ducks have been bred extremely rarely in captivity until recently. Close ground cover should be available for nesting. Ducklings are not easy to rear; they are difficult to start feeding initially.

(B29, B30, D1)

The following recommendations are made by an aviculturist with many years of success in keeping and breeding this species (V.w10):

  • Long-tailed ducks should be fed with high quality seaduck pellets, provided in hoppers at water level so that the ducks can feed from the water. Feeding stations requiring the ducks to come ashore to feed are not recommended. The diet should be supplemented with fish or shrimp from April to May or June (eggs are normally laid end of May to June) and from August to September. Green food such as Lemna (duckweed) is also appreciated.
  • Nesting areas on islands and peninsulas should be provided, with very good ground cover such as long grass and ferns sufficient to provide a canopy over the nest. Egg collection may be started once the second egg has been laid, replacing the eggs with very accurate dummy eggs and storing the eggs in a sand tray prior to setting under a broody hen. Eggs may be moved to an incubator at 17 or 18 days and to a very high humidity hatcher for hatching.
  • Long-tailed duck ducklings are difficult to rear. Hand rearing under infra-red lamps for heat is suggested. Two factors appear to be particularly important in rearing ducklings: getting them to feed and getting them onto water at an early age.
  • It is suggested that they must be on water with sufficient depth for diving (minimum 10 inches / 25cm deep) by four days old, and they must be eating well by this time. A very high protein starter crumb (28% protein) with a very small particle size is suggested; crumbs may be ground in a coffee grinder to reduce their size. Colour contrast may be used to promote feeding, for example feeding on a red mat. If necessary a little feed may be placed on water containing gammarids (freshwater shrimps) whose movement stimulates feeding behaviour. Finely chopped greenfood such as chopped Lemna (duckweed) should also be placed on the food; large quantities may be eaten. New seaduck diets developed in Germany, including a very small floating starter pellet appear to be useful.
  • By ten days old, the ducklings can be outside with access to a deep (e.g. six foot / 2 metres) pond, but with warmth provided by heat lamps. Concrete ponds may be used at this stage, although natural ponds are preferable.
  • N.B. these ducklings grow rapidly to fledge at 35 days old, with a growth spurt at about 14-16 days, therefore exercise and correct feeding are vital. Access to natural food such as gammarids and Lemna, and extra calcium in the diet (e.g. by grating cuttlefish bone over the feed) are suggested. Feeding stations may be placed out of water encouraging exercise from the water to the food and back again.
  • By 21days old at the latest they should be on a natural-type (not concrete) pond, in which they can search for food around the roots of marginal and bankside plants such as couch grasses. (V.w10)

Aviornis UK Ringing Scheme recommended average ring size: J 9.0mm (D8).

Individual Techniques linked in Wildpro

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External Appearance (Morphology)

Measurement & Weight

Length 15-23 inches 38-58cm (B3, B1)
Adult weight General About 650-800g (B1)
Male Average about 800g, maximum 1042g (B3); mean 1.8lbs. (B8).
Female Average about 650g maximum 815g (B3); mean 1.5lbs. (B8).
Newly-hatched weight --
Growth rate --

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Adult Bill Male Black with pink-yellow band and black nail (B2, B8, B25)
Variations (If present) Female: Dark/slate grey (B2, B8, B25).
Summer male: Black (B2, B25).
Eyes (Iris) Male Yellow-brown to orange-red (B2)
Variations(If present) Female: brownish (B2, B25)
Juvenile Bill Grey (B2).
Eyes (Iris) Brown (B2).

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Adult Male Blue-grey (B2, B3).
Variations (If present) --
Juvenile Grey (B25).

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Adult Male Male winter:- Head, neck, top of breast white, sides of head grey, sides of neck black, breast black-brown, underparts white, tail and upper tail coverts black. Scapulars white, elongated, pointed. Wings dark brown. (B3, B25).
Variations (If present) Female winter:- head and neck white with black/brown crown, cheek patches and neck ring. Breast mottled brown, underparts white, upperparts brown. (B3, B25).

Female summer:- head, neck, breast and upperparts mostly dark brown, underparts white, some white on head and neck. (B3, B25).

Male summer:- Head, neck and breast black, with white patch around eye, grey patch between this and bill. Abdomen and undertail coverts white, tail black with very long central feathers, upper tailcoverts and rump black; flanks pale grey. Upperparts brown, scapulars elongated, pointed, dark with reddish edges, Wings dark brown. (B3, B25).

N.B. Complex plumage changes, with spring and autumn plumages also variously described.

Juvenile Similar to female, duller, sides of breast darker, indistinct facial markings (B25).

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Newly-hatched Characteristics

General: Upperparts black-brown; underparts grey-white, brown band on breast, small white spots near eyes (B6).
Bill: Grey (B6).
Feet: Grey (B6).

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Reproductive Season

Time of year Begin May-June, depending on thaw (B1, B2, B25, B26)
No. of Clutches One, but re-lay if clutch lost (B2).

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Nest placement and structure

On the ground, often partially hidden by shrubs, boulders, trees, in natural depression, lined with vegetation and down (B1, B2, B3, B8, B25, B26, B27)

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Egg clutches

No. of Eggs Average 6-9 (B1, B2)
Range 8-11 (B8), 5-11, more by dump-nesting (B2); 2-11 (B1).
Egg Description Cream, yellow-buff or olive-buff (B2, B3, B8); size: 54x38mm (B3); weight: 43g (B3).

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24-29 days (B1, B2, B8).

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35-40 days (B1, B2, B8).

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Sexual Maturity

Males Two years old (B1, B2, B3).
Females Two years old (B1, B2, B3).

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Feeding Behaviour

Adults Mainly dive, reaching considerable depths (B1, B8, B25, B26).
Newly-hatched --

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Parental Behaviour

Nest-building Solitary or in loose groups, built by female (B1, B2).
Incubation By female (B2, B8).
Newly-hatched Tended by female, brooded initially; broods may merge (B2, B8).

Abandoned about time of fledging, sometimes earlier (B2, B8).

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Social Behaviour

Intra-specific Gregarious, usually found in groups, often nest in colonies, although breeding males are territorial (B8, B25, B26)
Inter-specific Frequently nests among Arctic tern colonies, and sometimes among eiders (B8, B27).

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Sexual Behaviour

Strong monogamous seasonal pair bond. Begin pair formation from late autumn onward; males leave females during incubation. Sometimes re-form pairs with same partners from previous year (B2, B3, B8, B25)

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Predation in Wild

Foxes, gulls, jaegers (B8).

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Activity Patterns

Flocks show synchronised diving, also form long lines and dive successively (B2)
Circadian Mainly daytime feeders (B2).

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Natural Diet


Crustaceans (mud crabs, crayfish, shrimps etc.), molluscs (mussels, whelks, periwinkles), other marine invertebrates, fish; fresh-water aquatic invertebrates important in summer. Perhaps 10% of diet seeds of grasses, pondweed, algae etc. (B1, B2, B3, B8, B25, B26, B27).

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Insect larvae, small crustaceans, small fish (B2, B3, B8, B27).

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Range and Habitat

Distribution and Movement (Migration etc.)


Circumpolar - Arctic coasts in summer (B1, B19).

  • London: In the London Area, a "scarce but annual visitor" with three females, one at each of three lcations, recorded during 2000. (J322.65.w1)

Migrate to seas as far south as Britain, South Carolina, Washington State, Japan, Korea. Inland in Great Lakes and large, deep central European lakes (B1, B19).

Occasional and Accidental

Accidental to Spain, Belgium, France, Czechoslovakia, Hungary, Austria, Switzerland, Italy, Yugoslavia, Rumania, Greece, Azores (B2).

Occasionally in winter reach Madeira Islands, southern Europe, Iran, eastern China, Japan, southern USA (B19).

Occasionally breeds on Orkneys, Shetlands (B27)



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Intraspecific variation


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Conservation Status

Wild Population -

Not globally threatened, common, widespread and numerous (B1, B8).

General Legislation
  • This species is listed on Schedule 1 - Part I (Birds protected by special penalties: Notes on the revised schedules state "Birds protected by special penalties at all times") of the LUK2 - Wildlife and Countryside Act 1981 of the United Kingdom. (W5.Oct01)
CITES listing Listing not yet included.
Red-data book listing Listing not yet included.
Threats Oil spills, fishing nets (B1, B8).

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Captive Populations

Not commonly kept or bred (B8).

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