Living Organisms / Animalia / Craniata / Aves / Ciconiiformes / Gaviidae / Gavia / Species
Gavia immer - Common loon (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)

  • Great northern diver.
  • Great northern loon.
  • Polar loon.
  • Ijsduiker (Holland).
  • Plongeon imbrin (France).
  • Eistaucher (Germany).
  • Strolaga maggiore (Italy).
  • Colimbo grande (Spain).
  • Svartnäbbad islom (Sweden).

(B19, B162)

Names for newly-hatched

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Names for non-breeding males or other colour-phases

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References

Species Author

Gordon McLeod

Species Editor

Debra Bourne

Major References

B162, B163, B164, B165, B166 

Aviculture references:

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

  • Grebes, Loons.

Specific Needs Group referenced in Management Techniques

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Aviculture Information

Notes

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Management Techniques

Click image for main Aviculture Section

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External Appearance (Morphology)

Measurement & Weight

Length Head to tail:
  • General: 69-91cm, including body of 43-56cm (B162); 73-88cm (B164); 70-80cm (B165); 69-81cm. (B166)

Wingspan:

  • General: 127-147cm (B162); 122-148cm. (B164)

Winglength:

  • General: 331-400mm. (B162)
Adult weight General 3600-4480g. (B162)
Newly-hatched weight --
Growth rate --

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Head

Adult Bill Summer / Breeding Straight and pointed; black. (B162, B164, B165, B166)
Winter / Non-breeding Straight and pointed; grey-white. (B162, B164, B165, B166)
Eyes Male Red. (B162, B164, B165, B166)
Variations (If present) --
Juvenile Bill Straight and pointed; grey with darker tip. (B162, B164)
Eyes (Iris) Red. (B162, B164)

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Legs

Adult Male Short; black. (B164, B166)
Variations (If present) --
Juvenile Short; black. (B164, B166)

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Plumage

Adult Summer / Breeding
  • Upperparts: Black and white checkered pattern; rump black.
  • Head: Greenish-black; nape black and white zebra-striped band.
  • Underparts: Throat black, with thin black and white zebra-striped band; breast white; belly white.
  • Wings: Upper black; underside white with black trailing edge.
  • Tail: Short and pointed; upper and under black.

(B162, B164, B165, B166)

Variations (If present) Winter / Non-breeding:
  • Upperparts: dark brown with grey-brown speckled banding.
  • Head: Dark brown.
  • Underparts: White.

(B162, B164, B165, B166)

Juvenile
  • As winter adult, with white tips to plumage on upper parts giving a scaled pattern.

(B162, B164, B165, B166)

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Newly-hatched Characteristics

Precocial, mobile, downy, eyes open, follow parents. (B163, B166)

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Reproduction

Reproductive Season

Time of year
  • From late May (B162); May to September. (B166)
No. of Clutches 1. (B163, B166)

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Nest placement and structure

  • Solitary nest site.
  • Mound of vegetation on ground.
  • Sometimes just a simple scrape instead.
  • Always located beside water.

(B162, B163, B166)

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Egg clutches

No. of Eggs Average 2. (B162, B163, B166)
Range 1-3. (B162, B163)
Egg description: Slightly glossy, narrow oval 90mm long; olive-green to dark brown with small dark brown spots, occasionally with black blotches.

(B162, B163, B166)

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Incubation

24-25 days (B162, B163); 29-30 days. (B166)

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Hatching

Asynchronous. (B163)

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Fledging

70-77 days (estimated B162), (B163); 12 weeks. (B166)

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Sexual Maturity

Males --
Females --

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Behaviour

Feeding Behaviour

Adults Chase and eat prey underwater. (B163)
Newly-hatched Fed by parents. (B163)

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Parental Behaviour

Nest-building By both birds. (B163)
Incubation By both parents. (B163)
Newly-hatched Fed by both parents. Chicks ride on adults' back. (B163)
Juveniles

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Social Behaviour

Intra-specific
  • Small flocks form at sea in winter.
  • Normally found singly or as breeding pairs.

(B162)

Inter-specific --

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Sexual Behaviour

  • Monogamous pair-bond, probably remain together over winter.

(B162, B163)

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Predation in Wild

Distraction display given by adults with chicks when predators approach. (B163)

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Activity Patterns

  • Swims.
  • Dives underwater from surface.
  • Takes off and lands on water.

(B166)

Circadian --

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Natural Diet

Adults

  • Fish of up to 28cm in length.
  • Crustaceans, molluscs.
  • Annelid worms, aquatic insects.
  • Amphibians.

(B162, B163)

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Newly-hatched

Small fish and aquatic invertebrates. (B163)

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Range and Habitat

Distribution and Movement (Migration etc.)

Normal Uncommon, western Palearctic population limited to north-west Europe; breeds in Iceland and Greenland. Widely distributed across North America as far south as the Great Lakes.

Britain: Uncommon resident in northern Scotland, winter visitor to British coastal waters.

  • London: In the London Area, a "scarce winter visitor and occasional migrant, often after hard weather." Mainly seenon various reservoirs. (J322.65.w1)

Migration:

  • From Greenland and Iceland, normally winter in Scotland.

(B162, B163, B166)

Occasional and Accidental Spitsbergen, Germany, Sweden (annually), Finland, Estonia, Lithuania, Poland, Hungary, Austria, Balearic Islands, Greece, Albania, Yugoslavia, Bulgaria, Romania, Ukraine, Turkey, Algeria, Morocco, Azores, Madeira.

(B162)

Introduced

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Habitat

  • Large freshwater lakes.
  • Coastal marine seas.
  • Island lakes and reservoirs (rarely).

(B162, B163, B166)

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Conservation

Intraspecific variation

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Conservation Status

Wild Population -
(Importance)

Icelandic population small (~300 birds), but widely distributed. (B162, B163)

General Legislation
  • All Divers are 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 Acid rain in North America. (B163)

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Captive Populations

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Trade

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