THE GENERAL BIOLOGY OF PENGUINS
135
and zonal terms applied to penguins must therefore be defined. In this
discussion I use the following terms:
Equatorial refers only to the Galapagos Islands and their vicinity;
tropical to the coasts of South America, southern Africa and Australia
southward to the tropic of Capricorn. Sub-tropical refers to the Juan
Fernandez Islands and the extra-tropical American coasts southward
to Coronel(37"S) in the west and BIthia Blanca (39"s) in the east - limits
,/+7
1OOOmllsr
,
\
0
Ld-%-Tristan da Cunha 0
Marion I.
c
\
,y
.Gough I.
*-------Sub-tropical convergence -Antarctic convergence
----Northern limit of pack ice
...*.... ' ..
PIG. 1. Localities and biogeographic boundaries in the southern hemisphere.
corresponding approximately to the 14°C annual isotherm for air; also
to the extra-tropical coasts of southern Africa and Australia, and to
Tasmania and the North Island of New Zealand.
Warm temperate refers to the Chilean, Argentine and New Zealand
coastlines between the above limits (14°C isotherm) and the 10" annual
isotherm for air, i.e. approximately to the 45th parallel; also to the
islands of the Tristan da Cunha group, St. Paul, New Amsterdam and
the Chatham Islands. Some of these lie athwart or to north of the subtropical convergence, but oceanic climates link them more closely with
temperate than with sub-tropical mainland coasts. Cold temperate includes the South American and New Zealand coasts below the 10°C