OF THE 35 SPECIES of seabirds that live south of the Antarctic Convergence, only 19 species breed on the Antarctic continent itself. Probably 100 million or more birds breed along the coast and offshore islands of Antarctica.
THESE INCLUDE the pelagic or free-ranging species such as the albatrosses and petrels. Coastal species, by contrast, forage close to the shore, and among them are found skuas, cormorants, terns and sheathbills.
MOST SEA BIRDS belong to the species Procellariiformes, which include the albatross (largest flying sea bird, with the wingspan of some species exceeding 4 meters), the fulmars, petrels, and shearwaters. The remaining regular sea bird species encompass shore birds– skuas, gulls, terns, and the penguin–doubtless the bird most popularly associated with the Antarctic.
THOUGH MOST of their time is spent in the water, all Antarctic seals, unlike whales, must return to land to breed. Breeding sites are found primarily on fast shelf ice and pack ice surrounding the Antarctic continent or on coastal shores of the more northerly islands. Breeding behaviors vary greatly among seal species. Ross, Weddell, and Leopard seals breed alone. Other species, such as the Antarctic Fur seal and the Southern Elephant seal prefer larger groups where dominant bulls aggressively defend ‘harems’ of females, with territorial disputes a common occurrence during breeding season.
MOST SEA BIRDS breed in large concentrations, owing to the scarcity of snow-free ground used for nesting. During the long austral summer, the birds have virtually an unlimited food supply in the nearby sea-zooplankton, cephalopods, and fish. The chicks develop quickly and soon fend for themselves until the approach of winter, when most species migrate north in pack ice or the open sea–some even to Arctic waters–in which they spend most of their lives.