154
R. STONEHOUSE
across, rising to over 9 000 ft (2 800 m). The icecap is relatively larger
than on South Georgia, and there are fewer sheltered harbours; both
flora and fauna lists are restricted. Sea and air are colder, and more
constant in temperature; the prevailing westerly winds have a cool
southerly component throughout the year. Coastal vegetation is sparser,
and partly replaced by feldmark or "wind-desert" plants which are
restricted to higher slopes on other sub-Antarctic islands. Macaroni
penguins are the most numerous species, nesting in large colonies at high
densities (Downes et al., 1959, pls. 16 and 19). Rockhoppers nest among
them, and in extensive colonies of their own on steeper ground. Gentoos
are plentiful, nesting on flat or rolling ground behind beaches where
landing is easy. King penguins are rare but increasing (Budd and Downes,
1965, p. 302).
g. Antarctic islands
The South Orkney, South Shetland and South Sandwich Islands,
Peter I Oy, Bouvetraya, the Balleny Islands and Scott Island lie within
the northern limit of pack ice. Although far apart and spanning a wide
latitudinal range, they are climatically and faunistically similar, differing
mainly in the length and intensity of their winters under the controlling
influence of the pack ice (Fig. 8b). All are ice-covered and precipitous.
Most of the flat ground suitable for penguin colonization is due to isostatic uplift from recent glacial retreat. There is little soil and no large
vegetation. Air temperatures seldom rise far above freezing point except
in sheltered microhabitats. The climate is cold, overcast and windy;
rain and sleet occur frequently in northerly weather, and snowfall may
be heavy in summer.
South Shetland Islands, a group of 11 large and many smaller islands,
extend in a chain over 300 miles between 53" and 63"W. Pack ice
surrounds the islands from March to early November, clearing first from
the western end of the chain; fast ice grows in sheltered bays in winter,
but does not persist. Macaroni and Chinstrap penguins breed in large
colonies on many of the islands, occupying open ground near the sea;
Gentoo and Ad6lie penguins are also present, often forming mixed
colonies. Eights (1838, pp. 211-212) recorded great numbers of King
penguins on the islands during a voyage of 1829-1830, but the species
now occurs rarely even as a vagrant.
South Orkney Islands, a group of two large and several smaller islands,
lie east and north of the South Shetland8 but have a cooler climate, due
to the proximity of the cold Weddell Sea Drift. Pack ice invests them
from March to December or January, allowing only a brief summer.
Precipitation is unusually heavy (about 40 cm equivalent rainfall,
making several feet of snow annually) and large snow accumulations are
R. STONEHOUSE
across, rising to over 9 000 ft (2 800 m). The icecap is relatively larger
than on South Georgia, and there are fewer sheltered harbours; both
flora and fauna lists are restricted. Sea and air are colder, and more
constant in temperature; the prevailing westerly winds have a cool
southerly component throughout the year. Coastal vegetation is sparser,
and partly replaced by feldmark or "wind-desert" plants which are
restricted to higher slopes on other sub-Antarctic islands. Macaroni
penguins are the most numerous species, nesting in large colonies at high
densities (Downes et al., 1959, pls. 16 and 19). Rockhoppers nest among
them, and in extensive colonies of their own on steeper ground. Gentoos
are plentiful, nesting on flat or rolling ground behind beaches where
landing is easy. King penguins are rare but increasing (Budd and Downes,
1965, p. 302).
g. Antarctic islands
The South Orkney, South Shetland and South Sandwich Islands,
Peter I Oy, Bouvetraya, the Balleny Islands and Scott Island lie within
the northern limit of pack ice. Although far apart and spanning a wide
latitudinal range, they are climatically and faunistically similar, differing
mainly in the length and intensity of their winters under the controlling
influence of the pack ice (Fig. 8b). All are ice-covered and precipitous.
Most of the flat ground suitable for penguin colonization is due to isostatic uplift from recent glacial retreat. There is little soil and no large
vegetation. Air temperatures seldom rise far above freezing point except
in sheltered microhabitats. The climate is cold, overcast and windy;
rain and sleet occur frequently in northerly weather, and snowfall may
be heavy in summer.
South Shetland Islands, a group of 11 large and many smaller islands,
extend in a chain over 300 miles between 53" and 63"W. Pack ice
surrounds the islands from March to early November, clearing first from
the western end of the chain; fast ice grows in sheltered bays in winter,
but does not persist. Macaroni and Chinstrap penguins breed in large
colonies on many of the islands, occupying open ground near the sea;
Gentoo and Ad6lie penguins are also present, often forming mixed
colonies. Eights (1838, pp. 211-212) recorded great numbers of King
penguins on the islands during a voyage of 1829-1830, but the species
now occurs rarely even as a vagrant.
South Orkney Islands, a group of two large and several smaller islands,
lie east and north of the South Shetland8 but have a cooler climate, due
to the proximity of the cold Weddell Sea Drift. Pack ice invests them
from March to December or January, allowing only a brief summer.
Precipitation is unusually heavy (about 40 cm equivalent rainfall,
making several feet of snow annually) and large snow accumulations are