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Imperial Shag
last update: Mar 24, 2009 11:49 PM
Also known as Heard Shag, Heard Island Cormorant, Blue-eyed Cormorant, Imperial Cormorant, Blue-eyed Shag
Latin name: Phalacrocorax atriceps
Population: It has a large global population estimated to be 340,000-1,400,000 individuals.
Cites classified: Least Concern (IUCN, 2008)
Where found: The Imperial Shag is widespread in the southern part of South America, the Falkland Islands, Prince Edward Islands, Iles Crozet, Head and Macquarie islands.
Wingspan: 124 cm
Length: 75 cm
Weight: not known
Mating/Breeding: The colonies are usually relatively small, but some consist of hundreds of pairs and are often shared with other seabirds such as Rock Shags, Southern Rockhopper Penguins and Black-browed Albatrosses. They lay 2 to 4 eggs in October/November that are placed in a nest made of seaweed and grass, and cemented together with mud and excrements. The eggs usually hatch in about 28 days, and are brooded by both parents.
Eggs: 2-4 pale green-blue eggs.
Hunting Habits: It catches its food by pursuit-diving. It may travel some distance from shore to fish. The Imperial Shag forages socially, flying in flocks, often swimming and diving synchronously.
Feed on: Small fish, crustaceans, squid and bottom-living invertebrates.
Threats: Many chicks and eggs are lost to predators such as skuas and sheathbills. Due to their small ranges and relatively small populations, they are highly susceptible to pollution and climate changes, and chance events such as storms.
Colour/Looks: The Imperial Shag is endowed with glossy black feathers covering most of its body, with a white belly and neck. It possesses a distinctive ring of blue skin around its eyes, an orange-yellow nasal knob, pinkish legs and feet, and an erectile black crest. During the non-breeding season, adults lack the crest, have a duller facial area, and less/no white to the back/wings.
Interesting Trivia:
- Even during the Antarctic summer, when most of the 24 hours enjoy daylight, shags return to roost in the traditional manner, before sunset.
- In this cold climate, they do not spread their wings to dry after diving in the manner so well known in temperate and tropical regions. Their inner plumage is extra dense.
More info:
- Hadoram Shirihai, A complete guide to Antarctic wildlife (2002)
- David McGonigal & Lynn Woodworth, Antarctica and the Arctic. The complete encyclopedia (2001)
- Tony Soper, Antarctica. A guide to the wildlife (2000)
