Kingdoms / Animalia / Craniata / Aves / Anseriformes / Anatidae / Aythya / Species
< >  Aythya marila - Greater scaup (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)

Scaup
Bluebill
Broadbill
Bergente (German)
Fuligule milouinan (French)
milouinan (French)
Porrón bastardo (Spanish)
Costero grande (Spanish)
Aythya marila marila European greater scaup
Aythya marila mariloides Pacific greater scaup
Fuligula marila

Names for newly-hatched

Duckling, downy.

Names for non-breeding males or other colour-phases

Eclipse

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References

Species Author

Debra Bourne

Major References

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

Other references:
B138

Aviculture references:
B29, B30, B31, B40, B94, B97, B128.w1, B129
D1, D8

ORGANISATIONS
(UK Contacts)

ELECTRONIC LIBRARY
(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

Notes

General information:
  • Pochards are diving ducks which spend most of their time on water, and are ungainly on land. They are generally hardy, sociable and easy to maintain in captivity. They should be kept with deep water available for diving, three to seven feet suggested (B29), or at least half the area 60cm and preferably one metre deep (D1), with shallow sloping banks for easy exit from the water, also islands, good marginal vegetation and loafing areas. Water providing a good supply of natural animal and vegetable food is preferred.
  • These ducks may be kept in mixed collections with dabbling ducks, including smaller species such as teal. They should be fed wheat in water, encouraging their natural diving behaviour. Pellets should also be fed. They may breed better if a group rather than single pair kept, as this allows their normal group displaying activity.
  • 12x12x14 inch (30x30x35cm) nest box with 5 inch (12.5cm) entrance hole suggested, placed under cover at the edge of the pond (B128.w1).

(B29, B40, B94, B128.w1, D1)

Species-specific information:

  • Greater scaup require a large, deep water area with water weeds and live food available, although they should also be provided with grain, pellets, bread and green food.
  • These ducks may be fairly readily bred in captivity. They nest in natural close cover, laying April to May. Ducklings are not difficult to hand-rear; they should be provided with water for swimming from an early age and require high-protein starter crumbs, duckweed and live invertebrates.
  • Fertile hybrids may result from crosses with Aythya affinis - Lesser scaup; hybrids (all sterile) also reported with Aythya spp., Bucephala clangula - Common goldeneye, Oxyura jamaicensis - Ruddy duck.

(B29, B30, B31, B40, B94, B97, B129).

Aviornis UK Ringing Scheme suggested average closed ring size:

  • Aythya marila marila European greater scaup K 10.0mm
  • Aythya marila mariloides Pacific greater scaup L 11.0mm

(D8)

Individual Techniques linked in Wildpro

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External Appearance (Morphology)

Measurement & Weight

Length 16-20 inches, 40-51cm (B3, B1)
Adult weight General 900-1250g (B1)
Male Average 1250g (B3).
Female Average 1200g (B3).
Newly-hatched weight --
Growth rate --

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Head

Adult Bill Male Blue-grey with black nail.
Variations (If present) Female: duller grey, dark culmen.
Eyes (Iris) Male Yellow.
Variations(If present) Female: yellow-brown
Juvenile Bill Dark grey.
Eyes (Iris) --

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Legs

Adult Male Grey.
Variations (If present) --
Juvenile Grey.

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Plumage

Adult Male Head and neck glossy green-black, breast black, tail, tailcoverts and rump black, flanks and abdomen white, upperparts grey with fine black vermiculations. Wing coverts grey vermiculated with black, secondaries white with black tips, primaries becoming more dusky.
Variations (If present) Female: Generally brown, head and neck darker and with white patch around bill and paler patch over ear as plumage becomes worn; flanks mottled grey-brown, abdomen whitish. Wing as male but coverts brown.

Eclipse: brown-black rather than glossy black, brown wash over paler areas.

mariloides subspecies stronger black vermiculations on upperparts.

Juvenile Duller and paler than female, less white around bill.

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Newly-hatched Characteristics

General: Upperparts dark brown, abdomen buff.
Bill: Grey.
Feet: Grey.

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Reproduction

Reproductive Season

Time of year Begins May (later further north).
No. of Clutches One clutch, re-nests if clutch lost.

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Nest placement and structure

In thick vegetation, grass and down lining.

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Egg clutches

No. of Eggs Average 8-11 (B1).
Range 8-11 (B8); 4-21 including dump-nesting (B1).
Egg Description Brown to olive or olive-grey (B3,B8) , 62x40mm, 67g (B3).

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Incubation

26-28 days (B1); 24-28 days (B8).

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Hatching

Synchronous.

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Fledging

40-45 days (B1); 35-45 days (B8).

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Sexual Maturity

Males One to two years old.
Females One to two years old.

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Behaviour

Feeding Behaviour

Adults Mainly dive, also upend in shallows and dabble on surface.
Newly-hatched Feed more from surface than do adults

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Parental Behaviour

Nest-building Solitary or loose groups, built by female.
Incubation By female.
Newly-hatched Tended by female although male may accompany family. Female broods at night initially.
Juveniles

Independent at or before fledging.

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Social Behaviour

Intra-specific Mainly gregarious, with flocks of hundreds to thousands outside breeding season.
Inter-specific --

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Sexual Behaviour

Seasonal pair bond. Male leaves during incubation in most cases.

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Predation in Wild

--

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Activity Patterns

--
Circadian --

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Natural Diet

Adults

Molluscs, also other invertebrates, small fish, seeds and green parts aquatic plants and sedges.

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Newly-hatched

Chironomid larvae, water-fleas, seeds.

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Range and Habitat

Distribution and Movement (Migration etc.)

Normal
  • A. m. marila Iceland, across northern Eurasia to Lena River in Siberia, mostly north of 60° latitude.
  • A. m. mariloides from Lena River eastward to Bering Sea and east through Aleutian island, Alaska and central Canada to Atlantic coast of Canada.

London: In the London Area, "regular but uncommon winter visitor and passage migrant, occasional large influxes during cold weather. Most records in 2000 were of single birds at a variety of sites. In Inner London, one individual was seen at Surrey Docks. (J322.65.w1)

Migrates to coast of western Europe, Black Sea, Caspian Sea, Atlantic and Pacific coasts of North America, Japan, Yellow and East China seas. Also inland to Great Lakes and central European lakes.

Occasional and Accidental

Accidental to Bear Island, Jan Mayan, Portugal, Spain, Greece, Iraq, Malta, Cyprus, Morocco, Tunisia, Azores.

Introduced

--

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Habitat

Tundra and tundra-fringe zone freshwater pools and lakes for breeding. Shallow inland coasts, estuary mouths, local inland freshwater lakes and reservoirs in winter.

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Conservation

Intraspecific variation

A. m. marila European greater scaup
A. m. mariloides Pacific greater scaup

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Conservation Status

Wild Population -
(Importance)

Reasonably abundant (B1).

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 Vulnerable to pollution as concentrate in large numbers at sea. Oil spills could threaten large percentages of the population (B1, B8).

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Captive Populations

Reasonably common in collections (B8).

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Trade

--

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