THE QENERAL BIOLOQY O F PENGUINS
167
The greatest penguin concentrations are found among eudyptids in
the temperate and sub-Antarctic zones, and among pygoscelids in the
Antarctic. About 4 000 000 Rockhopper penguins breed annually on
Gough Island; a single colony was estimated to hold 400 000 breeding
birds (Swales, 1965, p. 30). Nightingale Island to the north has 500 000
Rockhoppers (Elliott, 1957, p. 555), and a similar number of Royal
penguins occupies one of several colonies on Macquarie Island (Law and
Burstall, 1956, p. 21). Over a million Chinstrap penguins breed annually
on Laurie and Saddle Islands in the South Orkneys, and not less than
five million Adblies are estimated to breed on Laurie Island alone
(Clarke, 1915, pp. 224, 227). On the Antarctic continental coast Adklie
colonies numbering hundreds of thousands have been reported among
the Mackellar Islets and close to the Murray and Scullin Monoliths (Falla,
1937, pp. 81-82), Antarctic Peninsula (Sladen, 1958, p. 9) and Victoria
Land (Taylor, 1964, p. 568), but individual colonies do not often exceed
20 000-30 000 breeding birds.
The largest known Emperor penguin colony, at Coulman Island in the
Ross Sea, was estimated by Harrington (1959, p. 130) to contain over
100 000 breeding birds. Smaller colonies of 2 000 to 20 000 breeders are
more usual: Budd (1962, p. 380) has estimated the world population of
the species at only about 240 000 breeding birds. Concentrations of
tropical species tend to be much smaller. The total population of Blackfooted penguins, spread over many islets off southern and south-western
Africa, is estimated by Davies (1958, p. 9) at 130 000 birds, and that of
Galapagos penguins (LBvhque, 1964, p. 10) a t 1500 breeding birds,
spread along some 150 miles (240 km) of coastline.
In sub-Antarctic and cold temperate zones Gentoo and King penguins
are usually found in colonies numbering hundreds or thousands. The
largest known King penguin colony at Lusitania Bay, Macquarie Island,
numbers about 10 000 breeding birds (Downes et al., 1959, p. 16): much
larger colonies may have existed before the depredations of oil hunters
in the 19th century. Gentoos tend to breed in scattered groups of up to
500-1 000 nests, rather than in enormous colonies like their congeners.
Several groups may occupy a valley or hillside. A manuscript map of
Cooper Bay, South Georgia, by R. A. Brown of the British South Georgia
Expedition (1954-55), shows in a three-mile length of coastline (a) a
single large colony of 5 000 Macaroni penguins and two smaller adjacent
ones totalling about 2 000 birds, (b) one larga Chinstrap colony of about
1 500 birds, with four scattered small colonies each of 50-200 birds, and
(c) 32 separate small Gentoo colonies, the largest of about 1 000 birds,
the smallest with fewer than 50. Gentoo penguins, more than any other
colonial species, tend to shift their colony sites from year to year, possibly
as a defence against nest parasites (Stonehouse, in press).
B*
167
The greatest penguin concentrations are found among eudyptids in
the temperate and sub-Antarctic zones, and among pygoscelids in the
Antarctic. About 4 000 000 Rockhopper penguins breed annually on
Gough Island; a single colony was estimated to hold 400 000 breeding
birds (Swales, 1965, p. 30). Nightingale Island to the north has 500 000
Rockhoppers (Elliott, 1957, p. 555), and a similar number of Royal
penguins occupies one of several colonies on Macquarie Island (Law and
Burstall, 1956, p. 21). Over a million Chinstrap penguins breed annually
on Laurie and Saddle Islands in the South Orkneys, and not less than
five million Adblies are estimated to breed on Laurie Island alone
(Clarke, 1915, pp. 224, 227). On the Antarctic continental coast Adklie
colonies numbering hundreds of thousands have been reported among
the Mackellar Islets and close to the Murray and Scullin Monoliths (Falla,
1937, pp. 81-82), Antarctic Peninsula (Sladen, 1958, p. 9) and Victoria
Land (Taylor, 1964, p. 568), but individual colonies do not often exceed
20 000-30 000 breeding birds.
The largest known Emperor penguin colony, at Coulman Island in the
Ross Sea, was estimated by Harrington (1959, p. 130) to contain over
100 000 breeding birds. Smaller colonies of 2 000 to 20 000 breeders are
more usual: Budd (1962, p. 380) has estimated the world population of
the species at only about 240 000 breeding birds. Concentrations of
tropical species tend to be much smaller. The total population of Blackfooted penguins, spread over many islets off southern and south-western
Africa, is estimated by Davies (1958, p. 9) at 130 000 birds, and that of
Galapagos penguins (LBvhque, 1964, p. 10) a t 1500 breeding birds,
spread along some 150 miles (240 km) of coastline.
In sub-Antarctic and cold temperate zones Gentoo and King penguins
are usually found in colonies numbering hundreds or thousands. The
largest known King penguin colony at Lusitania Bay, Macquarie Island,
numbers about 10 000 breeding birds (Downes et al., 1959, p. 16): much
larger colonies may have existed before the depredations of oil hunters
in the 19th century. Gentoos tend to breed in scattered groups of up to
500-1 000 nests, rather than in enormous colonies like their congeners.
Several groups may occupy a valley or hillside. A manuscript map of
Cooper Bay, South Georgia, by R. A. Brown of the British South Georgia
Expedition (1954-55), shows in a three-mile length of coastline (a) a
single large colony of 5 000 Macaroni penguins and two smaller adjacent
ones totalling about 2 000 birds, (b) one larga Chinstrap colony of about
1 500 birds, with four scattered small colonies each of 50-200 birds, and
(c) 32 separate small Gentoo colonies, the largest of about 1 000 birds,
the smallest with fewer than 50. Gentoo penguins, more than any other
colonial species, tend to shift their colony sites from year to year, possibly
as a defence against nest parasites (Stonehouse, in press).
B*