Breeding Distribution

Watson et al. (1971) recognized five zoogeographical provinces in the Antarctic and Subantarctic regions. Of these, three are relevant to the Antarctic Sector of the Pacific : the Antarctic Continental Province which encompasses all the area south of the maximum pack ice limit, the New Zealand Province, and the Magellanic District of the Atlantic Province which includes the Chilean coast of South America. The composition of species within these provinces is shown in Table 10.1. Table 10.2 illustrates the breeding distribution of birds within the Antarctic Sector of the Pacific.

The Antarctic Continental Province

The Ross, Amundsen and Bellingshausen Seas adjacent to the Antarctic continent comprise the region's truly polar element. New Zealand and American ornithologists have studied the bird life from a number of research stations in the Ross Sea region (Young, 1981) such as those at Capes Adare, Bird, Crozier, Hallett and Royds (Fig. 10.1). Brief observations at the Ballenys and Scott, Possession, Franklin, Beaufort Islands and Terra Nova Bay have been made from ships travelling to and from the region.

Three species of penguins, Emperor (Aptenodytes forsteri), Adelie (Pygoscelis adeliae), and Chinstrap (Pygoscelis antarctica), six species of petrel, Cape Pigeon (Daption capense), Antarctic Fulmar (Fulmarus glacialoides), Antarctic Petrel (Thalas-soica antarctica), Snow Petrel (Pagodroma nivea), Antarctic Prion (Pachyptila desolata), Wilson's Storm Petrel (Oceanites oceanicus) and two species of skuas (Antarctic Skua Catharacta maccormicki and Southern Skua C. lonnbergi) breed on the continental coast and its adjacent islands (Table 10. 2).

Although the Antarctic Continental Province has only 11 breeding bird species, most of these have large populations. The avian population of the Ross Sea region alone was estimated by Ainley (1986) to be some 10 million birds, with an average density of 16 birds per km2 and a biomass of 44 kg per km2 (in December-early January). The avifauna is dominated in numbers by the Antarctic Petrel (55%), and in biomass by the Emperor Penguin (43%) and the Adelie Penguin (39%). The Ross Sea contains approximately one third of the world's population of Emperor and Adelie penguins (Wilson, 1983; Ainley et al., 1984; Harper et al., 1984).

The birdlife of the Marie Byrd Land coast and the coasts south of the Amund-

The composition of bird species within the zoogeographical zones of the Antarctic Sector of the Pacific.
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