Derivation
Cath-a-ract'-a - Gk, catarrhactes or catarractes, bird of prey: maccormicki - Robert McCormick (1800 - 1890), English naval surgeon and naturalist who collected the first specimen of this Skua on Possession Island in 1841
Anguilla, Antarctica (B), Antigua and Barbuda, Argentina, Barbados, Brazil, Canada, Chile, Costa Rica, Dominica, Falkland Islands (Malvinas), French Guiana, Guadeloupe, Japan, Maldives, Martinique, Mexico, Micronesia [Federated States of] (NB), Montserrat, Mozambique, Namibia, New Zealand, Panama, Peru, Seychelles, South Africa, South Georgia and the South Sandwich Islands, St Kitts and Nevis, St Lucia, St Pierre and Miquelon (NB), St Vincent and The Grenadines, Suriname, Trinidad and Tobago, USA (NB).
Vagrant to Australia, Comoros, Ecuador, Egypt, Greenland, India, Indonesia, Israel, Jordan, Kenya, Mauritius, Oman, Portugal, Somalia, Sri Lanka.
Unknown to Palau, Virgin Islands (British), Virgin Islands (U.S.).
Antarctic Continent and Peninsula, especially in Ross Sea area. Winters as far northern as Alaska and Greenland, though distribution in North Atlantic confused by presence of C. skua, and difficulties of field identification.
 
Population
Estimated population is 10,000 - 19,999 (2010).
South Polar Skua (Stercorarius maccormicki) [XC21526]
by Fabrice Schmitt from Aitcho Islands, South Shetland Islands, Antarctica, Antarctica (call, long call)
South Polar Skua (Stercorarius maccormicki) [XC254083]
by from Half Moon Island, South Shetland Islands, Antarctica (call)
Nest
A scoop of fine pebbles or gravel, unlined on a rocky knoll or mound, in carpets of moss, often close to or within colonies of penguins.
Eggs (Guide)
Usually 2, sometimes 1; rough to dull smooth with faint gloss, pale green faintly blotched brown or purple, or light grey distinctly blotched with brown and purple, or olive brown with numerous dark heavy blotches; oval; about 70 x 50 mm. Incubation: 27 - 29 days; by both sexes.
Young
Precocial or semi-precocial.
Subspecies
Great Skua (Catharacta skua), Southern Skua (Catharacta lonnbergi), Brown Skua (Catharacta antarctica) and South Polar Skua (Catharacta maccormicki) (Sibley and Monroe 1990, 1993), cross-regional species, are retained as separate species contra Christidis and Boles (1994) and Turbott (1990) who include lonnbergi and antarctica as subspecies of Great Skua (Catharacta skua) and AERC TAC (2003) who include South Polar Skua (Catharacta maccormicki) as a subspecies of Great Skua (Catharacta skua).
Occasional hybridization with subspecies lonnbergi of Brown Skua (Catharacta antarctica) reported.
No subspecies.
Similar Species
Dark morph with Southern Skua (Catharacta lonnbergi) which is larger, has a larger bill and darker in color.
References
See References.
The Field Guide to the Birds of Australia Pizzey, G., and Knight, E., 1997, Angus & Robertson, Sydney ISBN 0 207 19691 5
Field Guide to Australian Birds Morecombe, M., 2000, Steve Parish Publishing Pty Ltd. ISBN 1 876282 10 X
Field Guide to the Birds of Australia Simpson, K., and Day, N., 1999, 6th Edition, Viking ISBN 0 670 87918 5
Reader's Digest Complete Book of Australian Birds 1988, 2nd Edition, Reader's Digest ISBN 0 949819 99 9
What Bird is That? 1984, Revised Edition, Angus & Robertson, Sydney ISBN 0 207 14846 5
Handbook of Australian, New Zealand & Antarctic Birds 1990 - , Oxford University Press, Melbourne ISBN 0 19 553244 9