Many animals live in groups. Among seabirds in particular, most species form colonies during the breeding season. Although coloniality entails costs, such as increased competition for food and disease transmission, its repeated evolution across animal lineages suggests that group living provides important benefits.

One prominent hypothesis is that colonies allow individuals to acquire information about foraging sites from conspecifics. Knowing where food is located, and how profitable those sites are, can affect survival and reproductive success. When such information is acquired from conspecifics, it is referred to as social information. Yet, despite the presumed benefits of using social information, few empirical studies have tested from which conspecifics wild animals acquire such information or when they use it.

To address these questions, we examined which information sources Adélie penguins use when selecting foraging sites. We simultaneously and continuously tracked approximately one-third of the individuals in a small colony using biologging devices that recorded GPS locations and other behavioural data. During the chick-rearing period, Adélie penguins repeatedly undertake foraging trips from the colony to the sea and return to feed their chicks. By analysing these trips, we tested which information sources each individual used.

The study was conducted at an Adélie penguin colony in Torinosu Cove, Lützow-Holm Bay, Antarctica. The colony comprised 135 breeding pairs, of which 96–116 individuals were tracked simultaneously using GPS, corresponding to 35.6–43.0% of the active breeders.

We analysed movement data from 653 foraging trips. In many trips, Adélie penguins returned to foraging sites they had used during the previous trip (Fig. 2B), suggesting the use of information derived from personal experience.

Penguins also often departed the colony simultaneously with several conspecifics and travelled together towards foraging sites (Fig. 2A). In some of these groups, individuals visited foraging sites that had been used by their co-departing conspecifics during the previous trip (Fig. 2B). This indicates that, by departing and travelling with conspecifics, Adélie penguins can access social information about where others had previously foraged, enabling them to reach new foraging sites.

We also used dive-depth records to estimate foraging success during each trip. Penguins that had been less successful during their previous trip were more likely to change foraging sites on the next trip, and relied more on information held by conspecifics (Fig. 3). This use of social information based on a “win-stay, lose-shift” strategy — returning to the same site after success, but shifting sites after failure — may help penguins obtain more food over the breeding season.

Future directions

This study suggests that group departure and travel from the colony provide opportunities to acquire information about foraging sites. Building on this finding, future research can explore whether colonies of different sizes and in different environments function as information hubs in similar ways. Such research will improve our understanding of why animals live in groups and how they search for food in changing environments.