Chinstrap penguin breeding colonies are often enormous, with over 100,000 pairs congregating at some locations (4) (6). Breeding pairs form close bonds, with most individuals returning year after year to the same nest site with the same partner (3) (4). In late November, at the beginning of the Austral summer, the female usually lays two eggs, in a nest comprising a circular platform of small stones with a shallow nest cup (3) (4) (6) (7). The male and the female share incubation duties, and also take it in turns to attend the chicks after they hatch (3) (5). Unlike other penguin species, chinstrap penguin parents do not give preferential treatment to stronger offspring, but instead feed both chicks equally (4) (5) (7). The chicks usually fledge when they are around seven to eight weeks old, but breeding success is highly variable, with a much smaller proportion of chicks surviving in years when sea-ice persists near the colonies, restricting sea-access for foraging adults (3) (4) (6) (7).
During the breeding season, the chinstrap penguin forages close to the breeding grounds, spending most of its time near the surface at depths of less than 40 metres (2) (4). A specialist feeder, crustaceans, and in particular krill, form the bulk of this species’ diet (2) (3) (4). Prey is caught by pursuit-diving at all times of the day and night, with most effort concentrated around noon and midnight (3) (4) (7). At sea, the leopard seal is the main predator, while on land sheathbills and skuas are a threat to chicks and eggs (5) (7). To move about on land, the chinstrap penguin will often toboggan on its belly, propelling itself forward with its feet (7).
In autumn, the chinstrap penguin leaves the breeding colonies and heads for the open waters north of the pack-ice, where large groups congregate over winter (2) (5) (7). It is only in the following spring, around October, that this gregarious bird makes its way back to land and the breeding colonies (2).