Description
& Characteristics:
Large, heavily built birds, skuas are closely related to members
of the gull family.
In North America the coastal skuas are known as jaegers. Two
species of skuas are found in the southern oceans: the Antarctic
or the Brown, and the South Polar. Antarctic skuas breed on
most of the southern islands and may be distributed as far
north as the subtropics, while South Polar skuas occur primarily
on the Antarctic continent, although sightings have been recorded
as far north as Greenland and the Aleutian Islands. South
Polar skuas are often seen following ships at sea. In winter
after the breeding season, both skua species migrate northward
spending most of their time at sea.
In appearance, skuas look like immature gulls, although heavier,
more robust and menacing in mien. They have conspicuous white
patches at the base of their flying feathers, wedge-shaped
tails, and a black, short heavy bill. Their flight is heavy,
with relatively little gliding and much flapping.
All
skuas are fiercely predatory, and the species of the Southern
Ocean, are no exception. During the summer South Polar skuas
stake territories near Adélie
penguin rookeries on the coast, raiding them for eggs,
chicks, and also cleaning up carrion. Thus, they have earned
the nickname, 'raptor of the south'. The diet of Antarctic
skuas is more broad depending on season and their locality.
They may scavenge and predate upon other seabirds and their
young and eggs, or they may roam the southern oceans feeding
on fish, molluscs, squid, and crustaceans (mainly krill &
copepods).
South
Polar skuas arrive at their breeding colonies in late October
to mid-December. They nest in sheltered areas adjacent to
penguin colonies. The
nests are shallow depressions on the ground and are often
found on rocky outcrops, moss covered cliffsides or valley
floors. South Polars will generally lay two mottled eggs which
hatch in late December to late January after an incubation
period of 24 to 34 days.
Antarctic skuas also breed during the summer months, typically
laying two eggs in nests located on elevated grasslands or
in sheltered rocky areas in close association with prey species.
They will defend their territories vigorously against all
intruders including other skuas and petrels.
Some birds choose not to nest in the colonies, but will establish
solitary nesting sites. Breeding
skuas are highly territorial and will attack unwelcome intruders
to their nests by flying straight for the head with claws
outstretched.
The estimated
lifespans of both South Polar and Antarctic skuas are approximately
11 years.
