Adélie penguins are a medium-sized species characterized by their black and white plumage and a prominent white ring around each eye. They have a black head and chin, and a stubby black bill with a dark red base and tip, partially covered by feathers. These birds inhabit the Southern Ocean, primarily around the coasts and islands of Antarctica, often found within the limits of the pack ice. They spend most of the year at sea, utilizing their flipper-like wings for underwater swimming.
Daily Life and Foraging
Adélie penguins forage in their marine environment. They predominantly feed on krill, such as Euphausia superba and E. crystallorophias, but also consume fish, amphipods, and cephalopods. While they can dive to depths of 170 to 175 meters (about 560 feet), they prefer to hunt within the first 50 to 70 meters (about 165 to 230 feet) of the water’s surface, where light availability is greater. The number of foraging dives per hour and the frequency of undulations during dives are indicators of their feeding success.
Adélie penguins often forage in groups, a strategy that helps reduce predation risk and increases the efficiency of locating food. During the chick-feeding phase, adults make foraging trips to provision their young. When environmental conditions make prey access more difficult, penguins may undertake longer foraging trips and deliver less food to their chicks.
Social and Reproductive Behaviors
Adélie penguins are highly social, especially within their large colonies, where communication is important. Males initiate courtship by performing a “salute,” standing about 4 meters from a female and engaging in beak thrusting, neck arching, and extending to their full height. This display also serves to establish the male’s territory within the colony, and interested females respond by raising their heads and stretching tall. Courtship bowing, a motion between pairs, can help reduce tension and the risk of aggression.
Upon returning to their nesting sites from October to March, Adélie penguins construct nests primarily from small stones. Both parents are actively involved in nest building and are known to steal stones from neighboring nests. Mated pairs are protective of their nest sites, using vocal warnings and physical displays, including flipper beating, to defend against rivals.
Incubation of the eggs, typically two, lasts around 36 days, with males and females taking turns while the other forages. After hatching, parents share the responsibility of caring for the young, with the nestling period lasting approximately 60 days. Adults use unique calls to locate their chicks in the crowded colonies, which is important for family bonding.
Seasonal Movements
Adélie penguins undertake significant annual movements between their breeding grounds and winter foraging areas. After the breeding season, between March and April, they migrate westward, then northward from May to August as the sea ice edge expands. These migratory movements follow the sea ice and are influenced by the west-flowing Antarctic Slope Current and wind. They shift further north to avoid the perpetual polar night and remain within the pack ice, reaching their maximum distance from the colony in June to early August.
These migrations are driven by the need to follow food sources, primarily krill, which thrive under the sea ice, and to avoid the harsh conditions of the Antarctic winter. During the winter, penguins dive deeper, reaching depths of up to 129 meters, and stay on ice overnight. They return towards their breeding colonies from late August through October, with pre-breeding foraging allowing them to build up fat reserves for fasting during breeding. The assistance of sea ice movement helps them cover greater distances with less effort during these journeys.