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Life in the Southern Ocean
Factfile |
 Life in the Southern Ocean |
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Birds of the Antarctic
Antarctica has no resident land birds and virtually all the birds that come there are based around the sea as ultimately they rely on the sea for their food. Of the world’s 310 or more species of seabirds, less than 50 are found south of the Polar Front. This is a low figure compared to other parts of the world, but the actual number of birds within each species is huge. Penguins are thought to number 17 – 20 million breeding pairs, while petrels are estimated at 150 million birds.
Giant petrel chick
The Giant petrel, like other petrels, is long winged, with a wingspan of 2 metres (6.5 feet). Giant Petrels are vicious scavengers, eating most things including dead seals and whales. They use their powerful hooked beaks for feeding and for killing other birds. Petrels can fly fast and low, close to the surface of the water. This enables them to take krill from the water with ease. Other types of petrel found in Antarctica include the Snow petrel and Wilson’s storm petrel. The life cycle of birds, like so many animals in Antarctica, is dependent on the food available. Most of the birds lay their eggs in early summer, when the sea is full of the plankton and krill needed to feed the young. The young birds can then eat a lot of food, grow quickly and be strong enough to survive the winter.
To survive in the cold, birds of the Antarctic have frost bite resistant feet and fat stored under their skins, for insulation (to keep warm) and as a food reserve, if needed. On top of this, many layers of feathers work to trap the body heat and stop it from escaping.
The petrels together with the albatrosses make up the majority of Antarctica’s seabirds. Both birds belong to an order of birds, the Procellariiformes, who have tube-like nostrils on top of their beaks. Most scientists think the function of these nostrils is to excrete excess salt from fishing and drinking seawater.
Albatross
Several types of albatross can be found in the Antarctic area. All of them only come ashore to build nests in order to breed, feeding their young through regurgitation. Albatrosses are legendary birds; partly because of their great size but also because they inhabit such remote and storm-ridden seas.
The Black-Browed albatross has the highest population numbers in Antarctica. It eats mainly krill, but also fish and squid, flying over the Southern Ocean in search of food. Albatrosses all breed for life and while mortality is very high in the first year, those which survive, can reach ages well over 50.
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