Far From Land The Mysterious Lives of Seabirds

where seabirds find food | 153

feeding chicks on New Zealand’s offshore islands to fly there, a round-
trip trek of 4,000 km.^12
Earlier I described how, during winter, the King Penguins of the
Crozets head past the Polar Front, reaching as far south as the ice edge.
In summer the ice edge retreats and is further from their colony, per-
haps too far. Instead satellite- tracked birds that are incubating or brood-
ing small chicks preferentially exploit the Polar Front about 400 km
south of the colony.^13 The penguins swim south to the Front at speeds of
7– 8 km/h. On reaching it, they slow down to about 5 km/h; they enter
searching mode. This is particularly obvious where the sea surface tem-
perature gradient is at its steepest. Then, job done, they speed up once
more to 7– 8 km/h for the journey home.^14

A map of the Southern Ocean showing the approximate positions of

the the Subtropical (STF), the Subantarctic (SAF), and the Antarctic

Polar Fronts (APF), and the Southern Antarctic Circumpolar Current

Front (SACCF) encircling the continent of Antarctica.

30 ° E

60 ° E

90 ° E

18 0° E 15 0° E 12 0° E

60 ° W 30 ° W 0°

15 0° W

12 0° W

90 ° W

(^60) ° S
(^30) °
S
APAPFF
sAsACCCCFF
SASAFF
STSTFF