Description & Characteristics:
One of the most common and well-known of all Antarctic penguin species, Adelie penguins can be found forming colonies on islands, beaches and headlands all around the Antarctic coast. The sight of thousands of them waddling and sliding to the water’s edge and then, at the appropriate moment, diving headlong into the frigid Antarctic waters, has thrilled Antarctic visitors for generations. Early explorers made use of the ubiquitous Adelie not only for endless entertainment but also as a source of eggs and tough, but tasty meat. Scientists today use the Adelie as an indicator species to monitor the abundance of krill, so important to the web of Antarctic life.
The Adelie penguin is the stereotypical penguin. With its white ‘tuxedo shirt’ front, and the white ring around its eyes, the bird has a handsome, yet comical appearance. Its beak is reddish with a black tip.
Adelies vacate their winter quarters on the comparative warm Antarctic ice pack and arrive at the rookeries during September and October, often scampering several miles over the sea ice to reach their ancestral coastal homes. They typically establish dense colonies on the ice-free slopes of rocky coasts, headlands and islands. Competition for nesting sites can be fierce and the older more dominant birds tend to stake nests in the middle of the colony where they are better protected from marauding skuas.
A mating pair of Adelies will build a rocky nest of small stones carried in the birds’ beaks and dropped into place. Two greenish-white eggs are usually laid in early November. Males and females take turns incubating the eggs, however, the female returns to the sea first, often leaving the male to stand alone for up to ten days while she feeds.
Hatching occurs after about 35 days. The chicks are brooded closely by their parents for the first two to three weeks. While the two chicks hatch almost simultaneously, inevitably one chick is stronger and is better able to win food, which is regurgitated from the crop of whichever parent is present at the time. Growing rapidly, the chicks soon develop a thick woolly gray down and quickly become almost as large as their parents. During the third or fourth week they huddle with other chicks in nursery groups called ‘crèches’ for both protection and warmth. This leaves the parents free to go to sea on feeding forays in order to satisfy their chicks’ increasing appetites. Often, a parade of adults can regularly be seen moving between the colony and the sea on such feeding trips. By late March most of the chicks can swim and the Adelies then depart for the pack ice and the sea.
The Adelie’s main oceanic predators are leopard seals which often lie in wait beneath the ledges to snare the first penguin into the water.