General
Information
With
the end of the long polar winter comes the arrival of millions
of seabirds to breed. First to arrive are the Adelie
penguins who have walked as much as 50 kilometers across
the sea ice to reach their nesting grounds. They are followed
soon after by the petrels
and skuas, flying
in from the open sea. Of the 35 species of seabirds that
live south of the Antarctic Convergence, only 19 species
breed on the Antarctic continent itself. Probably 100 million
or more birds breed along the coast and offshore islands
of Antarctica. These include the pelagic or
free-ranging species such as the albatrosses
and petrels. Coastal species, by contrast, forage close
to the shore, and among them are found skuas, cormorants,
terns and sheathbills.
Most of the sea birds belong to the species Procellariiformes,
which include the albatross (largest flying sea bird, with
the wingspan of some species exceeding 4 meters), the fulmars,
petrels, and shearwaters. The remaining regular sea bird
species encompass shore birds-- skuas, gulls,
terns, and the penguin--doubtless
the bird most popularly associated with the Antarctic.
Most
sea birds breed in large concentrations, owing to the scarcity
of snow-free ground used for nesting. During the long austral
summer, the birds have virtually an unlimited food supply
in the nearby sea-zooplankton, cephalopods, and fish. The
chicks develop quickly and soon fend for themselves until
the approach of winter, when most species migrate north
in pack ice or the open sea--some even to Arctic waters--in
which they spend most of their lives.
The
Antarctic sea birds have evolved to gain features that help
conserve body heat--waterproof plumage, a layer of subcutaneous
fat, and large, compact bodies.
Back
to Main Wildlife Page
