A highly gregarious species, the king penguin gathers in breeding colonies, ranging in size from the small, around 30 birds, to the immense, hundreds of thousands of birds (3) (4). When ready to mate, a male will advertise its availability with trumpet-like calls, and by stretching tall, with its bill elegantly upraised (2) (5). During pair formation, both sexes engage in an elaborate display of head shaking, strutting, bowing, calling, and high-pointing, where a couple stand face-to-face, and slowly rise to their full height before relaxing again (2). A single egg is laid between November and April, with both parent birds sharing incubation duties in two to three week cycles (2) (3). Instead of building a nest, the egg is incubated on top of the feet under the warm belly, with each pair’s somewhat mobile territory defined simply by pecking-distance (2) (4) (5). After hatching, parental duties continue to be equally shared by both sexes, with one staying on land to brood the chick while the other goes in search of food at sea (2) (3) (4). When the chick reaches around six weeks old, it joins a group of chicks known as a crèche, thus allowing both parents to go foraging at the same time, in order to bring back enough food for the voracious offspring (2) (3). The crèche provides the woolly chicks with protection from predators, as well as the benefit of collective warmth (2). The winter is a testing time for the young chicks, as a scarcity of food forces the parents to spend longer periods at sea, during which time the chicks must fast (2) (4). As a result, chicks that are born late in the breeding season, and therefore weigh less by on the onset of winter, face a much greater risk of not surviving through till spring (2). Those that come through the winter having survived the combined hazards of predation, starvation and freezing temperatures, eventually fledge at around 10 to 13 months old (3). The consequence of this long chick-rearing period, is that the king penguin typically only produces two chicks every three years (3) (4) (5). Although a breeding pair is monogamous whilst raising a chick, only a very small proportion of individuals mate with the same partner the following breeding season (2).
While chicks remain in the colonies year-round and breeding adults must return throughout the winter to feed the chicks, immature birds and non-breeding adults commonly disperse far from the colonies (4). With a body designed for efficiency in water, the king penguin is an expert swimmer and diver (2) (3). In the pursuit of fish and squid, which form the bulk of the diet, the king penguin generally dives down to around 50 metres, but will sometimes descend as deep as 300 metres, particularly during the winter when food is scarce (2) (5) (8). Whilst on land, skuas, sheathbills and giant petrels are a constant threat to young birds and eggs. At sea, however, the main predators of the king penguin are leopard seals and killer whales (4).