An Afternoon with Adélie penguins
One of only four penguin species to nest on the continent itself, the Adélie penguin (Pygoscelis adeliae) is found along the coast of Antarctica and throughout the surrounding islands. Occasionally, vagrant penguins have been seen in southern Australia, New Zealand, and tip of South America. the They thrive in the cold, travelling between fridgid coastal ice sheets in the winter and pebbly coastal beaches in the summer.
The Adélie penguin is among the smaller penguins, at its tallest about 75cm and weighing between 3.8-8.2kg. Generally females are quite a bit smaller than males. Their faces and backs are covered entirely in waterproof black feathers, save a white ring around the eye, and have white bellies. P. adeliae also tends to be slimmer than other, larger penguin species, perhaps to make them more streamlined in the water, where they spend most of their time.
The primary food source for P. adeliae is krill, supplemented seasonally by fish and squid. Although they usually hunt in the upper water column for such prey, they can dive down to 175m. They migrate about 13,000 kilometres each year as they travel from foraging grounds to breeding colonies and back again. In the winter, ice provides plenty of room for hunting krill, and in the summer the ice receeds to the rocky continental and island coasts, where Adélie penguins nest. Year-round predators include leopard seals and killer whales, and in the summer birds can snatch eggs and hatchlings.
Though Adélie penguins have no formal social structure, they are highly social creatures. Groups of anywhere from a dozen to a hundred individuals travel together between seasons, hunt together, and frequently call to each other. Adélie penguins also serially monogamous; they stay with one mate throughout a breeding season, and the next season both mates choose whether to return to their nest or search for a better mate. More often than not, pairs will stay together throughout multiple seasons.
At the beginning of the mating season, in spring, single males will begin to build nests from the pebbles along the shore. They also perform loud displays, throwing their head and wings back and puffing out their chests. The female chooses a mate, and shortly after lays one or two eggs. These eggs incubate for about 36 days, cared for by both parents, and the ensuing chick is looked after and fed for another 4 weeks. In some cases individuals, particularly young individuals proper lacking social cues or experience, will pair with another individual of the same sex. However, both homosexual and heterosexual pairings only last a single season, as adults and young leave together on their annual migration.
Conservation status: The IUCN has rated P. adeliae as Least Concern. They face some threat from industrial fishing, as bycatch and from loss of prey. However, global warming is the larger concern as melting ice reduces the available habitat for hunting, migration, protection from predators, and nesting grounds.
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Photos
Kristin Raw
Kate Kloza
Megan Cimino
Todor Iolovski
