All About Animals

The king penguin is able to breed at three years of age, although only a very small minority actually do then; the average age of first breeding is around 5–6 years. King penguins are serially monogamous. They have only one mate each year, and stay faithful to that mate. However, fidelity between years is less than 30%. The unusually long breeding cycle probably contributes to this low rate. The king penguin has an extremely prolonged breeding cycle, taking around 14–16 months from laying to offspring fledging. Although pairs will attempt to breed annually, they are generally only successful one year in two, or two years in three in a triennial pattern on South Georgia. The reproductive cycle begins in September to November, as birds return to colonies for a prenuptial moult. Those that were unsuccessful in breeding the previous season will usually arrive earlier. They then return to the sea for around three weeks before coming ashore in November or December.

The female penguin lays one pyriform (pear-shaped) white egg weighing 300 g. It is initially soft, but hardens and darkens to a pale greenish colour. It measures around 10 cm × 7 cm. The egg is incubated for around 55 days with both birds sharing incubation in shifts of 6–18 days each. They balance the egg on its feet and incubates it in a brood pouch. Hatching may take up to 2–3 days to complete, and chicks are born semi-altricial and nidicolous. In other words, they have only a thin covering of down, and are entirely dependent on their parents for food and warmth. The guard phase begins with the hatching of the chick. Similar to the emperor penguin, The young king penguin chick spends its time balanced on its parents' feet, sheltered in the brood pouch formed from the abdominal skin of the latter. During this time, the parents alternate every 3–7 days, one guarding the chick while the other forages for food. The guard phase lasts for 30–40 days. By then the chick has grown much larger, and is better able to both keep warm and protect itself against most predators. King chicks are very curious and will wander to explore their surroundings. The chicks form a group, called a  crèche and are watched over by only a few adult birds; most parents leave their chick in these crèches to forage for themselves and their chick. Other species of penguins also practice this method of communal care for offspring.  

By April, the chicks are almost fully grown, but lose weight by fasting over the winter months, gaining it again during spring in September. Fledging then takes place in late spring/early summer.

King penguins form huge breeding colonies; for example, the colony on South Georgia Island at Salisbury Plain holds over 100,000 breeding pairs and the colony at St. Andrew's Bay over 100,000 birds. Because of the very long breeding cycle, colonies are continuously occupied year-round with both adult birds and chicks. During breeding, king penguins do not build nests, however they show strong territorial behaviour and keep a pecking distance to neighbouring penguins. Penguin positions in breeding colonies are highly stable over weeks and appear regularly spaced, but thus far no quantitative analysis of the structural order inside a colony has been performed. The king penguin feeds its chicks by eating fish, digesting it slightly and regurgitating the food into the chick's mouth. Because of their large size, king penguin chicks take 14–16 months before they are ready to go to sea. This is markedly different from smaller penguins, who rear their chicks through a single summer when food is plentiful. King penguins time their mating so the chicks will develop over the harshest season for fishing. In this way, by the time the young penguins are finally mature enough to leave their parents, it is summer when food is plentiful and conditions are more favorable for the young to survive alone at sea.