Shared With Magellanic District

Sooty Shearwater sen and Bellingshausen Seas has been little studied, largely because of the vast and impenetrable pack ice that dominates this region. Adelie Penguins, Snow Petrels and Antarctic Skuas are known to breed in Marie Byrd Land (information reviewed in Harper et al., 1984). Recently, Broady et al. (1989) reported 10,000 nests of Antarctic Petrels on Edward VII Peninsula. Peter I Island, the only oceanic island in the southeastern part of the region, is reported to have a few breeding Adelie and Chinstrap Penguins, Antarctic Fulmars, Cape Pigeons, Snow Petrels and Wilson's Storm Petrels (Holgersen, 1951; Fevolden, 1987). Antarctic Skuas may also breed there.

The distribution of Adelie Penguin breeding sites illustrates the uneven distribution of birds along the Antarctic coast of the Pacific. Adelie Penguins nest on stony areas free of ice and snow. They also nest adjacent to seas where winter fast ice regularly breaks out in spring, so that food is close by in mid-December to feed the newly hatched chicks. Of more than 1 million pairs of Adelie Penguins breeding in 45 colonies along approximately 10,000 km of coastline, over 90% nest in 26 colonies along one 1,500 km stretch — the western fringe of the Ross Sea from Ross Island to Cape Adare (Fig. 10.2). In this area, where inshore sea ice breaks up earlier than elsewhere there are several very extensive Adelie Penguin colonies including the largest known — Cape Adare with over 240,000 breeding pairs. Along the remaining 8,500 km of the Antarctic coast — encompassing the Bellingshausen and Amundsen Seas, Marie Byrd Land, Pennell Coast and Oates Land — where solid shelf ice commonly occurs until late in summer, only 19 scattered colonies are known, and only two of these are thought to contain more than 5,000 pairs each (Table 10.3). This coast has, however, been poorly surveyed.

Fig. 10.1. Nesting Adélie Penguins at Cape Royds, Antarctica.
Breeding distribution of Antarctic and Subantarctic seabirds within the Pacific Sector.

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