Family Cormorants (Phalacrocoracidae)

Least Concern

Imperial Shag (Leucocarbo atriceps)


Taxonomy

French: Cormoran impérial German: Kaiserscharbe Spanish: Cormorán imperial
Other common names: Imperial Cormorant
Taxonomy:

Phalacrocorax atriceps

P. P. King

, 1828,

Strait of Magellan

.

Sometimes placed in genus Notocarbo or occasionally in Phalacrocorax, but classification here follows results of a comprehensive molecular phylogeny for the entire family#R. Race albiventer formerly considered a separate species (and then including birds of Falkland Is and parts of mainland South America), but wide zone of sympatry where mixed pairs frequent, and no differences observed in either behaviour or osteology; thus, albiventer constitutes only a race or possibly even a colour morph. Races bransfieldensis, georgianus, nivalis, melanogenis and purpurascens have been treated as full species#R#R (as in HBW), but differences between them never rigorously documented, and in some cases supposed diagnostic characters appear weak, few or possibly non-existent (as e.g. in case of georgianus#R); these taxa therefore all reabsorbed here into P. atriceps, but distinctive taxon verrucosus is retained as a species (which see). Name albiventer erroneously emended to albiventor#R#R. Seven subspecies currently recognized.

Subspecies and Distribution
  • L. a. atriceps P. P. King, 1828 – Imperial Shag – S South America in Chile (S from Mocha I) and S Argentina (S from Chubut).
  • L. a. albiventer (Lesson, 1831) – Falkland Is.
  • L. a. bransfieldensis Murphy, 1936 – Antarctic Shag – Antarctic Peninsula, South Shetland Is and Elephant I.
  • L. a. georgianus Lönnberg, 1906 – South Georgia Shag – South Georgia, South Orkney Is, South Sandwich Is and Shag Rocks (Scotia Sea).
  • L. a. nivalis Falla, 1937 – Heard Shag – Heard I, in SE Indian Ocean.
  • L. a. melanogenis (Blyth, 1860) – Crozet Shag – Crozet Is and Prince Edward Is, in S Indian Ocean.
  • L. a. purpurascens (J. F. Brandt, 1837) – Macquarie Shag – Macquarie I and nearby Bishop and Clerk Is (S of New Zealand).
  • Descriptive notes

    c. 68–76 cm; male 2104–3341 g, female 2087–2400 g (nominate), male 3022 g, female 2576 g (bransfieldensis), male 2883 g, female 2473 g (... read more

    Voice

    During breeding, male gives barking “aark” and various other calls, also barks in aggression;... read more

    Habitat

    Exclusively marine in most of its range; forages in subantarctic waters along coast and around... read more

    Food and feeding

    Birds of all races typically forage by pursuit diving, feeding alone or in small groups. Large feeding flocks, of up to thousands of birds... read more

    Breeding

    Laying reported Jun–Jan, becoming progressively later with higher latitude: typically Oct–Dec in S races. Forms colonies,... read more

    Movements

    Basically sedentary. Island races especially seldom travel any distance. However birds of the... read more

    Status and conservation

    Not globally threatened (Least Concern). There are major populations on mainland South America and in Falkland Is, with many large colonies. Common in Chile, though suffers... read more

    Recommended citation

    Orta, J., Garcia, E.F.J., Christie, D.A., Jutglar, F. & Kirwan, G.M. (2019). Imperial Shag (Leucocarbo atriceps). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from https://www.hbw.com/node/52649 on 19 June 2019).