This species nests on ice-free rocky coasts, often in extensive open areas to accommodate typically large colonies, which may be far from the open sea at the time of arrival (Emmerson et al. 2011). Females lay one, or more usually two eggs, which are incubated by both sexes in alternating shifts.

The species mainly feeds on krill, fish, amphipods, cephalopods and jellyfish (Thiebot et al. 2016), though these latter three taxa are probably of minor importance. It captures such prey by pursuit-diving to maximally 150-180 m, with the majority of foraging down to 30 m (Watanuki et al. 1997, Lyver et al. 2011, Ropert-Coudert et al. 2018b), becoming deeper as shallow prey are depleted at least off large colonies (cf Ainley et al. 2015, Cimino et al. 2016b) during the summer breeding period. During winter, dives tend to be deeper than during summer (maximally to 130 m), with foraging constrained by short day-length (Takahashi et al. 2018). Adélie Penguins tend to winter far enough north that there is some daylight each day (Ballard et al. 2010), as they are hesitant to dive into the water during darkness for fear of not being able to see predators (Ainley and Ballard 2011).

The species is migratory. Patterns of movement are well-known for adults during breeding, with foraging within 10-180 km of the coast depending upon colony size (Ballance et al. 2009). Foraging trips can be as far as 380 km during the incubation period (Clarke et al. 2006). During the non-breeding period, adults move into the pack-ice up to 1,000-2,500 km from the breeding colony, depending upon the distance to the sea ice edge (e.g. Clarke et al. 2003, Ballard et al. 2010, Dunn et al. 2011, Hinke et al. 2015, Takahashi et al. 2018, Thiebot et al. 2019, Warwick-Evans et al. 2019). In most cases, this involves moving to the north, although individuals in the northern Antarctic Peninsula shift east or west, and those of the central western Antarctic Peninsula shift south; previously, when winter sea ice was more persistent, there was little movement, with many individuals remaining in the vicinity of their colony sites year round (Parmelee et al. 1977). Patterns of movement for juveniles are poorly known, but during their first year they remain in the pack-ice (Ainley et al. 1984).

Conservation Actions Underway
This is one of the most studied penguin or seabird species (del Hoyo et al. 1992, Ainley 2002) and is the subject of on-going research throughout its circumpolar range. A number of breeding sites are designated as Antarctic Specially Protected Areas (ASPAs), especially in regions with human traffic. The foraging areas of some colonies are located within Marine Protected Areas (MPAs). The Ross Sea Region Marine Protected Area (RSR MPA) protects a number of colonies, though not moulting areas; other proposed MPAs elsewhere in Antarctica should afford protection for other colonies. Well-designated MPAs, coupled with protection at breeding sites, through either MPAs or ASPAs, are likely to be the most effective means for conservation, as both breeding sites and foraging areas will then be protected.
Human disturbance and scientific research are strictly regulated.

Conservation Actions Proposed
Continue to monitor population trends and relate to the extent and persistence of sea ice and associated climatic variables. Carry out further research into the species's ecology to improve understanding of how environmental changes and human activities, such as fishing, will affect the population. Demographic research is needed, as is more work on the species's wintering ecology and its ecological, spatial and temporal overlap with fish and krill extraction. Improved understanding of all factors driving population change is needed, including for those species that potentially compete for the same prey resource as Adélie Penguins, whether recovering populations of seals, cetaceans or large fish. Such information will help to improve predictions of future environmental changes and how these will impact the species's population.