The Adélie penguin is an Antarctic penguin, closely related to the gentoo and chinstrap penguins. Together, these three species are known as the brushtail penguins. The Adélie penguin is a relatively small species with a black back and head, a white front, and a characteristic white ring around the eyes.
Though Adélie penguins live mostly on the continent of Antarctica (and a few associated islands), they mate and nest on rocky shores, rather than on the ice. Both parents take turns caring for a clutch of two eggs that are laid in a stone nest. While one parent incubates the eggs, the other parent feeds. Adelie penguins are foraging predators that will take many different prey items, but their preferred food source is krill. Their reliance on this particular prey source, however, is a relatively recent phenomenon that seems to align with the decline of other krill predators (e.g., fur seals and baleen whales) as a result of overhunting. Regardless, the Adélie penguin’s current diet consistently includes several krill species. When individuals are not nesting, they are known to undergo long, winter migrations in search of food, staying close to the expanding ice edge and using the ice to rest.
One interesting behavior of the Adélie penguin is its reluctance to be the first individual that enters the water. This species is known to form dense groups at the water’s edge waiting for an individual to either fall or be pushed into the water. Only after that first individual is seen safely swimming away to feed do the others in the group follow. This behavior is thought to be used to avoid predation by leopard seals, killer whales, and other large animals. Adélie penguins have no natural land predators and are extremely curious about people. They often walk right up to researchers as if conducting their own studies.
The Adélie penguin is the subject of numerous scientific studies and is generally considered to be one of the best studied penguins. Researchers have been studying Adélie penguin behavior for many decades. Unfortunately, continuing expansion of research facilities reduces nesting area, potentially contributing to this species’ status as near threatened with extinction. Though population trends are currently positive, scientists worry that overfishing of Southern Ocean krill and other prey species may threaten the Adelaide Penguin’s ability to maintain stable populations. Furthermore, even though this species does not reproduce on the ice surface, researchers predict that climate change will negatively affect the Southern Ocean food web, possibly counteracting any positive influence on Adelaide Penguin nesting areas that ice retreat may provide. Finally, this species spends much of the year in the Ross Sea and would undoubtedly benefit from adoption of the proposed marine protected area in that region that is currently being considered by world governments who have an interest in Antarctica.