South polar skua

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South polar skua
South polar skua.jpg
A south polar skua in Terra Nova Bay
Scientific classification Red Pencil Icon.png
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Charadriiformes
Family: Stercorariidae
Genus: Stercorarius
Species:
S. maccormicki
Binomial name
Stercorarius maccormicki
(Saunders, 1893)
Stercorarius maccormicki map.svg
Synonyms

Catharacta maccormicki

The south polar skua (Stercorarius maccormicki) is a large seabird in the skua family, Stercorariidae. An older name for the bird is MacCormick's skua, after explorer and naval surgeon Robert McCormick, who first collected the type specimen. This species and the other large skuas, such as the great skua, are sometimes placed in a separate genus Catharacta.

Contents

Description

The south polar skua is a large bird (though small compared to other skuas sometimes placed in Catharacta) that measures around 53 cm (21 in) in length. Adults are greyish brown above, and have a whitish (pale morph) or straw-brown (intermediate morph) head and underparts, and the contrast between head and body makes it easy to separate from similar species with good views. Juveniles and adult dark morphs are harder to distinguish from their relatives, and more subjective or difficult-to-observe criteria, such as the colder brown plumage and blue bill base, must be used.

Identification

Distinguishing this skua from the Northern Hemisphere Arctic, pomarine, and long-tailed skuas is relatively straightforward. The large size, massive barrel chest, and white wing flashes of this bird are distinctive even at a distance. The flight is direct and powerful. Identification of this skua is more complicated when it is necessary to distinguish it from the closely related great skua of the North Atlantic, and the other large Southern Hemisphere skuas. Identification problems make claims of any Southern Hemisphere skua in the eastern North Atlantic problematic, and few records of south polar skua have been accepted in Western Europe. Similar problems occur, of course, with extralimital claims of great skua.

Distribution and habitat

Skua eggs Skua eggs.jpg
Skua eggs
Skua chick Skua chick.jpg
Skua chick

It breeds on Antarctic coasts, usually laying two eggs in November and December. It is a migrant, wintering at sea in the Pacific, Indian, and Atlantic Oceans. In the eastern North Atlantic, it is replaced by the great skua. South polar skuas have been seen at the actual Geographic South Pole. Megalestris Hill, on Petermann Island in the Wilhelm Archipelago of Antarctica, is named after an obsolete generic name for the south polar skua. [2]

Behavior

Like other skuas, it flies at the head of a human or other intruder approaching its nest.[ citation needed ]

Feeding

The south polar skua eats mainly fish, often obtained by robbing gulls, terns and even gannets of their catches. It also eats other birds, rabbits, and carrion. Like most other skua species, it continues this piratical behavior throughout the year, showing less agility and more brute force than the smaller skuas (jaegers) when it harasses its victims.

Related Research Articles

Skua Family of birds

The skuas are a group of predatory seabirds with seven species forming the genus Stercorarius, the only genus in the family Stercorariidae. The three smaller skuas, the long-tailed jaeger, the parasitic jaeger, and the pomarine jaeger are called jaegers in American English.

Long-tailed jaeger Species of bird

The long-tailed skua or long-tailed jaeger is a seabird in the skua family Stercorariidae.

Great black-backed gull Species of bird

The great black-backed gull is the largest member of the gull family. Described by the Cornell Lab of Ornithology as "the king of the Atlantic waterfront", it is a very aggressive hunter, pirate, and scavenger. It breeds on the European and North American coasts and islands of the North Atlantic and is fairly sedentary, though some move farther south or inland to large lakes or reservoirs. The adult great black-backed gull has a white head, neck and underparts, dark grey wings and back, pink legs and yellow bill.

Parasitic jaeger Species of bird

The parasitic jaeger, also known as the Arctic skua, Arctic jaeger or parasitic skua, is a seabird in the skua family Stercorariidae. The word "jaeger" is derived from the German word Jäger, meaning "hunter". The English "skua" comes from the Faroese name skúgvur[ˈskɪkvʊər] for the great skua, with the island of Skúvoy known for its colony of that bird. The general Faroese term for skuas is kjógvi[ˈtʃɛkvə]. The genus name Stercorarius is Latin and means "of dung"; the food disgorged by other birds when pursued by skuas was once thought to be excrement. The specific parasiticus is from Latin and means "parasitic".

Pomarine jaeger Species of bird

The pomarine jaeger, pomarine skua, or pomatorhine skua, is a seabird in the skua family Stercorariidae. It is a migrant, wintering at sea in the tropical oceans.

Great skua Species of bird

The great skua, sometimes known by the name bonxie in Britain, is a large seabird in the skua family Stercorariidae. It is roughly the size of a herring gull. It mainly eats fish caught at the sea surface or taken from other birds.

Thick-billed murre Species of bird

The thick-billed murre or Brünnich's guillemot is a bird in the auk family (Alcidae). This bird is named after the Danish zoologist Morten Thrane Brünnich. The very deeply black North Pacific subspecies Uria lomvia arra is also called Pallas' murre after its describer. The genus name is from Ancient Greek ouria, a waterbird mentioned by Athenaeus. The species term lomvia is a Swedish word for an auk or diver. The English "guillemot" is from French guillemot probably derived from Guillaume, "William". "Murre" is of uncertain origins, but may imitate the call of the common guillemot.

Wilsons storm petrel Species of bird

Wilson's storm petrel, also known as Wilson's petrel, is a small seabird of the austral storm petrel family Oceanitidae. It is one of the most abundant bird species in the world and has a circumpolar distribution mainly in the seas of the southern hemisphere but extending northwards during the summer of the northern hemisphere. The world population has been estimated to be more than 50 million pairs. The name commemorates the Scottish-American ornithologist Alexander Wilson. The genus name Oceanites refers to the mythical Oceanids, the three thousand daughters of Tethys. The species name is from Latin oceanus, "ocean".

Petermann Island Island of Antarctica

Petermann Island is a small, low and rounded island, lying off the northwest coast of Kyiv Peninsula in Graham Land, Antarctica, a short distance south of Booth Island and the Lemaire Channel. It is a popular tourist destination.

Brown skua Species of bird

The brown skua, also known as the Antarctic skua, subantarctic skua, southern great skua, southern skua, or hākoakoa (Māori), is a large seabird that breeds in the subantarctic and Antarctic zones and moves further north when not breeding. Its taxonomy is highly complex and a matter of dispute, with some splitting it into two or three species: Falkland skua, Tristan skua, and subantarctic skua. To further confuse, it hybridizes with both the south polar and Chilean skuas, and the entire group has been considered to be a subspecies of the great skua, a species otherwise restricted to the Northern Hemisphere.

East Antarctica Part of Antarctica that lies within the Eastern Hemisphere

East Antarctica, also called Greater Antarctica, constitutes the majority (two-thirds) of the Antarctic continent, lying on the Indian Ocean side of the continent, separated from West Antarctica by the Transantarctic Mountains. It lies almost entirely within the Eastern Hemisphere and its name has been accepted for more than a century. It is generally higher than West Antarctica and includes the Gamburtsev Mountain Range in the center. The geographic South Pole is located within East Antarctica.

Chilean skua Species of bird

The Chilean skua, also called the cinnamon skua, is a large predatory seabird, which breeds in Argentina and Chile, but ranges as far north as Brazil and Peru when not breeding. A relatively distinctive skua, it has a dark cap that contrasts with its cinnamon throat and lower face. Hybrids with the brown skua are known from southern Argentina.

Antarctic tern Species of bird

The Antarctic tern is a seabird in the family Laridae. It ranges throughout the southern oceans and is found on small islands around Antarctica as well as on the shores of the mainland. Its diet consists primarily of small fish and crustaceans. It is very similar in appearance to the closely related Arctic tern, but it is stockier, and it is in its breeding plumage in the southern summer, when the Arctic tern has shed old feathers to get its non-breeding plumage. The Antarctic tern does not migrate like the Arctic tern does, but it can still be found on a very large range. This tern species is actually more closely related to the South American tern.

References

  1. BirdLife International (2012). "Catharacta maccormicki". IUCN Red List of Threatened Species . 2012. Retrieved 26 November 2013.
  2. "Megalestris Hill". Geographic Names Information System . United States Geological Survey . Retrieved 2013-09-12.

Further reading

• Udayakumara, A. A. D. A., D. M. S. S. Karunarathna, A. A. T. Amarasinghe and E. M. K. B Ekanayake (2007). First confirmed record of South Polar Skua Catharacta maccormicki Saunders, 1893 (Aves: Stercorariidae) from Western Province, Sri Lanka. Birding Asia, 8: 83–84.