Stercorariidae

Skuas and Jaegers

A small group of parasitic birds of the gull family. Some of them are very migratory and can be found at both sides of the equator.

There are two genera: Catharacta and Stercorarius. The Skuas are a group of large, mostly dark brown birds, with a pale morph in only one species. The Jaegers  are the smaller representatives of this group with elongated central tail feathers and different color morphs.

Genus Catharacta

Skuas

The five species of skuas are more or less of the same size and appearance. The South Polar Skua Catharacta maccormicki  has three color morphs and might show a lighter colored bill in most birds of the dark morph and blue in young birds of the pale morph. Other great skuas have dark brown bills. The Great Skua Catharacta skua is the only northern hemisphere species, which sometimes also has a bill with a pale base. So far no skulls of the southern species are available for this website.
Great Skua skulls develop in the same manner as those of the alcids, slowly growing a supraorbital ridge.

• Great Skua Catharacta skua, North Atlantic down to north-west Africa and USA east coast.

• South Polar Skua Catharacta maccormicki, Coasts of Antarctica, Antarctic peninsula, South Shetlands, up to Alaska, Greenland and northern Indian Ocean.

• Chilean Skua Catharacta chilensis, both coasts of South America up to the tropics.

• Antarctic or Southern Skua Stercorarius antarcticus, two subspecies:

•    C. a. antarctica, Coastal Argentina and Terra del Fuego, Falklands

•    C. a. hamiltoni, Gough I. and Tristan da Cunha group to New Zealand, South America and Antarctica.

• Brown Skua Catharacta. lonnbergi, circumpolar Southern Hemisphere up to the tropics.