Natural factors such as storms or abnormally extensive sea ice can cause extremely high mortality in nesting areas. But Antarctic bird species have evolved to overcome these adversities. Human activity is another matter. On the evolutionary time scale, people and their machines have just entered the Antarctic scene. The birds have had little time to adjust. Studies have shown that even casual or occasional contacts with Antarctic bird colonies can adversely affect breeding success. After visits are ended or controlled, bird populations have been observed to return to former levels.
Also essential to their continued vitality are scientific studies in conjunction with sound management and conservation. Today, much is known about some of these birds at breeding sites, but virtually nothing about the longer time they spend at sea.
To preserve the natural state of Antarctic bird populations, people have had to learn how to behave when around them. This writing, prepared by two experienced ornithologists in co-operation with the National Science Foundation, is intended to assist visitors to Antarctica in adjusting their activities when near birds so that they can avoid affecting the birds’ behaviour and land breeding pattern.
The birds and their habitat
Snow petrels and Antarctic petrels nest on nun attacks (isolated peaks that protrude through glacial ice) as far as 200 miles inland. These far-inland nesting petrels thus fly enormous distances to the sea to get food for their young.
South polar skuas are the only birds recorded at the South Pole. They are spectacular migrants, have been recorded in Greenland, British Columbia, and Japan.
The name penguin is from two old Welsh names meaning, “white head”. Seafarers in past centuries evidently were thinking of the flightless (now extinct) great auk of the North Atlantic, which had much white on its head. Penguins and great auks resemble one another, but otherwise are unrelated.
Only a few species reside year-round in the high latitudes close to Antarctica; they include some gulls, terns, penguins, cormorants, and petrels. Most move to sub Antarctic seas in winter. A few flying birds travel to the Northern Hemisphere.
Southern kelp gulls retain their primitive mollusc-feeding behaviour and other life styles only in Antarctica, where pristine conditions prevail. In Southern Hemisphere areas of modern agriculture and industrialisation, their lives are dramatically different, as they have largely become dependent on human refuse for food. Sadly, even in Antarctica they learn quickly to rely for food on open dumps and hand feeding.
Antarctica limpets are one of few large molluscs among a sparse of invertebrate animal assemblage able to overcome the scouring action of moving ice in the shore zone, where kelp gulls depend on them year-round. Distributions of kelp gulls and limpets are closely linked.
Antarctic grass, one of the only two species of flowering plants, grows in the Antarctic Peninsula area. Skuas and especially gulls use it for nests. Penguins nesting close by make their nests of small stones. The Antarctic convergence is the oceanic area where cold waters flowing northward meet and under run warmer, southward flowing water.
This area, as well as the northern edge of the sea ice, can be particularly productive for marine life, and birds sometimes are seen in large numbers there.
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