The south polar skua (Catharacta maccormicki) belongs to the family of skuas, Stercorariidae.
These species of skuas are distributed in coastal Antarctica (breeding populations) and also in several countries bordering Pacific, Indian and Atlantic Oceans. The south polar skua is a vagrant visitor to Indian coasts. These skua species are trans-equatorial migrants, moving from their breeding grounds in coastal Antarctica to their wintering grounds far away in Arctic region.
- Appearance, description and pictures
- Distribution and habitat
- Feeding and breeding habits
- Migration and conservation status
South polar skua - Overview
- Scientific name: Catharacta maccormicki
- Species author: (Saunders, 1893)
- Synonyms/Protonym: Stercorarius maccormicki H. Saunders, 1893
- Family: Stercorariidae › Charadriiformes › Aves › Chordata › Animalia
- Vernacular names: English: South polar skua, Chinese: 灰贼鸥, French: Labbe de McCormick, German: Antarktikskua, Spanish: Págalo polar, Russian: Южнополярный поморник, Japanese: ナンキョクオオトウゾクカモメ, Indonesian: Burung Skua Kutub, Malay: Burung Pelangi Antartik
- Other names: Antarctic Jaeger, Antarctic Skua, McCormick's Jaeger, McCormick's Skua
- Distribution: Coastal Antarctica, Countries bordering Pacific, Indian and Atlantic Oceans
- Diet and feeding habits: fish, birds, rabbits, carrion
- IUCN status listing: Least Concern (LC)
Appearance, physical description and identification
The south polar skua (Catharacta maccormicki) is a large stocky gull-like bird, measuring 50 to 55 cm in length and weighing 900 to 1600 grams. The wingspan is 10 to 140 cm.There are three morphs, pale, dark and intermediate. The paler morph adults have grayish brown upper parts and whitish head and underparts. The darker morph has dark grayish brown upperparts and straw-brown head and underparts. The bill is blackish, stubby and has hooked tip. The eyes and legs are black. The wings have white markings. Their call is a repeated "ah-ah-ah" sound.
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| Birds of India - Image of South polar skua - Catharacta maccormicki |
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| Indian birds - South polar skua - Catharacta maccormicki by Tony Morris |
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| Birds of India - Picture of South polar skua - Catharacta maccormicki |
Origin, geographical range and distribution
The south polar skua is distributed in Coastal Antarctica (breeding populations) and also in several countries bordering Pacific, Indian and Atlantic Oceans. There are several Important Bird and Biodiversity Areas (IBA) of south polar skua species existing in Antarctica.Some of the (IBA) of south polar skua species are Avian Island, Blue Glacier, Cape Chocolate, Cape Crozier, Ross Island, Caughley Beach, Cape Bird, Cierva Point, Dailey Islands, Edmonson Point, Half Moon Island, Hop Island, Rauer Islands, Lagotellerie Island, Point Hennequin, King George Island, Possession Island, Gregory Island and Franklin Island.
Ecosystem and habitat
These south polar skua species do not occur normally in forest. They inhabit various coastal marine ecosystems. They inhabit sea cliffs, rocky offshore islands, marine intertidal rocky shoreline and tide pools and also shallow marine areas with submerged kelp, seagrass and other macroalgae. They inhabit neritic marine areas with subtidal rocks, pebbles, mud and sand.Diet and feeding habits
The diet of these species is mostly fish. They also feed on birds, rabbits and carrion. They are kleptoparasites and the fish is usually obtained by robbing gulls, terns and gannets of their catches. They exclusively feed on penguins, if their breeding colony is close to a penguin rookery.Reproduction and breeding habits
The breeding season of these south polar skua species starts from November. Loose breeding colonies are located on relatively snow-free areas in the Antarctic coast with greater densities in the Ross Sea area. The nest is scraped ground and is unlined. Usually two eggs are laid. They intimidate and confront any intruder approaching their nest and make repeated high-speed stoop attacks on intruder.Migration and movement patterns
These south polar skua species are fully migratory birds, undertaking a trans-equatorial migration.They depart from their breeding grounds located throughout the Antarctic coast, especially in the Ross Sea area, in the month of March. Their wintering grounds of south polar skua are located as far north as Alaska (USA), Canada, Greenland, Iceland, Norway and Denmark. They return to the breeding grounds is in October and November.
Conservation status and concerns
The global population size of the south polar skua (Catharacta maccormicki) is estimated to be around 6000 to 15000 individual birds. The overall population size is considered to be stable. Their generation length is 17.1 years.The south polar skua does not approach the thresholds for being Vulnerable either under the range size criterion or under the population trend criterion or under the population size criterion. The IUCN (International Union for Conservation of Nature) has categorized and evaluated the south polar skua (Catharacta maccormicki) and has listed it as of "Least Concern".
| Taxonomy and scientific classification of Catharacta maccormicki | |
|---|---|
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Aves |
| Order: | Charadriiformes |
| Family: | Stercorariidae |
| Subfamily: | - |
| Genus: | Catharacta |
| Species: | C. maccormicki |
| Binomial name: | Catharacta maccormicki |
| IUCN status listing: |  Least Concern |
1.Image source: https://commons.wikimedia.org/wiki/File:South_polar_skua.jpg
Image author: Paride Legovini | License: CC BY-SA 4.0
2.Image source: https://www.flickr.com/photos/tonymorris/8053449594/
Image author: Tony Morris | License: CC BY-NC 2.0 (as on 2016-12-12)
3.Image source: https://commons.wikimedia.org/wiki/File:South_Polar_Skua_From_The_Crossley_ID_Guide_Eastern_Birds.jpg
Image author: Richard Crossley | License: CC BY-SA 3.0
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