Emperor penguins are restricted to the waters of the Antarctic zone within limits of pack-ice. They breed on sea-ice between 66 and 78 degrees south in colder conditions than any other bird species and are the only species of penguin that does not breed on land. The population at Coats Land, where Halley Station is situated, is estimated to have 14 300 - 31 400 breeding pairs. The appearance of males and females is similar, with no seasonal variation and juvenile penguins are separable from adults by their plumage.
The life cycle and behaviour of emperor penguins have been studied for a number of years. Both sexes have loud trumpeting and agonistic calls and low sexual display calls. Display calls are vital for individual recognition and pair formation, which occurs from April to May. Females lay a single large egg (460-470 grams) in May-June and adults typically associate closely in large groups or huddles during the period of egg incubation. Following laying, females return to sea after fasting for up to 45 days and males are responsible for the whole of incubation (approximately 64 days). The male may fast for 115 days by the time the chick hatches and feed the chick a proten-rich oesophageal curd secretion for the first few days prior to the return of the female with food. When the female returns, both parents may brood their chick resting on their feet for 50 days following hatching and alternate for feeding trips. Starving males have been observed to head for ice-free polynyas (permanent areas of open water) which give them the fastest possible access to food. Chicks grow rapidly, their thin primary down being replaced by a thicker secondary down for better insulation. They form large creches until departure from the colony in December-January, at about 150 days. Adults undergo a period of moulting in Jan-Feb, lasting 30-40 days. Birds may spend from January to March at sea.
Penguin statistics....Emperor penguins generally take fish, small cephalopods and crustaceans. They can weigh over 30 kilograms and reach a height of up to 115 centimetres. All penguins are flightless and have streamlined bodies, which reduces drag while swimming at sea. Their stiff, flat flippers provide powerful propulsion during swimming. Their short legs restrict penguins to a waddling gait on land but, although this appears inefficient, they are in fact surprisingly agile and capable of travelling considerable distances. They "toboggan" on their bellies over snow and ice, using their feet and flippers for propulsion. Emperor penguins can dive to depths of 400-450 metres and may travel up to 150-1000 kilometres in a single foraging trip. The mean longevity of the emperor penguin is estimated at 19.9 years, with perhaps 1 per cent of eggs laid giving rise to adults 50 years of age.
General facts.....Only Emperor and Adelie penguins are restricted to the Antarctic. Most species occur in more northerly temperate areas of the Southern Hemisphere, with a single species occuring on the equator at the Galapagos Islands. The greatest concentration of penguins does occur around the Antarctic and sub-Antarctic. Penguins appear primarily adapted for a marine existence, yet they remain dependent on land for breeding, rearing of young and for moulting. The Emperor Penguin is unique in rearing its chick throughout the long dark winter months, below minus 40 degrees Celcius. All penguins are largely monogomous, mating with only a single partner each year. About 15 per cent of pair-bonds persist over several years, with most breeding with a different partner in successive years.
Penguins account for 89-90 per cent of avian biomass and are close to the top
of the food chain in the Southern Oceans. Four penguin species share characteristics
with crabeater and sub-Antarctic fur seals, Minke whales and the black-browed
albatross which have been identified as those most useful as indicators of changes
in food (mainly krill) availability. Humans threaten penguins because we can
bring about climate change which influences ocean productivity and we degrade
and alter both terrestrial and marine habitats upon which penguins depend.
Acknowledgement: The information above is taken from The Penguins by Tony D. Williams, published by Oxford University Press 1995.