(Aptenodytes forsteri).

Emperor Penguins grow up to 1.15 metres in height and weigh between 20 and 40 kilograms. Flightless, they are noted for their rigidly upright stance while they are moving, a bearing they abandon only if alarmed or threatened. They reach sexual maturity after 3 to 6 years and have a lifespan of around 20 years. Their closest relative is the more northerly King Penguin, Aptenodytes patagonicus, which looks similar, but is smaller, reaching 0.95 metres and weighing between 10 and 20 kilograms.

Courtship starts in March and the female lays a single egg in mid-May - late autumn or early winter in that part of the world. While the female returns to the sea to replenish her supplies of fat, the egg is incubated by the male who endures a 40 to 60 day fast through the harsh winter cold and blizzards. The egg, carried on the bird's feet, is covered with a fold of skin to ward off the cold of the ice and the sub-zero air temperatures. During the Antarctic winter, when the sun never rises, Emperor Penguins must face the most severe weather in the world. They are protected by a very dense plumage and a thick layer of blubber. They also huddle together in their hundreds to conserve heat and form a wind break on the vast, exposed ice fields.

The female returns just as the egg is about to hatch and takes over the last few days of incubation and then broods the chick for about 40 days. The male, having lost over half his body weight, returns to the sea to feed. By that time, sea ice has often encroached huge distances out to sea, leaving the exhausted males with a long trek back to the feeding grounds to regain their lost fat reserves. As soon as the chick is large enough to be left in a creche with other young, both parents hunt for food. The young rapidly become independent and set out for the sea, on their own, in December.

Despite the cumbersome appearance on land, Emperor penquins are proficient, but not rapid, swimmers and efficient predators in the sea. They can dive to depths of over 250 metres in search of food. Emperor Penguins do not have the light, air-filled bones of flying birds, making it possible to stay submerged for up to 18 minutes, propelling themselves through the water with their flippers and using their feet and tail to steer. They catch fish, squid, shrimps and other crustaceans, using their sharply tipped bill.

The Emperor Penguin has few natural enemies and lives in a habitat where few other animals can survive. Although it numbers around 300,000 birds, increased fishing and pollution of the southern polar seas would seriously threaten their long-term survival. Sources: How Birds Live, Robert Burton, 1977. Australia's Wilderness Heritage - Flora & Fauna, 1988. 'IMP Wildlife Fact File', Card 10 Group 2, 1999.

• 1992 Silver Birds of Australia $10 and Piedfort.