Foraging conditions for breeding penguins improve with distance from colony and progression of the breeding season at the South Orkney Islands.

摘要: Background According to central place foraging theory, animals will only increase the distance of their trips if more distant prey patches offer better opportunities. Thus, theory predicts that breeding seabirds in large colonies could create a zone food depletion around colony, known as "Ashmole's halo". However, seabirds' decisions forage at particular are likely also complicated by stage. After chicks hatch, parents must return frequently feed offspring, so may be less visit patches, even quality is higher. interaction between availability, intra-specific competition, and stage on not well understood. The aim this study was address question chinstrap penguins Pygoscelis antarcticus colony. In particular, we aimed investigate how affects strategy; whether birds far from colony higher than available locally; there evidence for intraspecific indicated depletions near increasing over time, longer trips. Methods We used GPS temperature-depth recorders track movements 221 4 sites South Orkney Islands during incubation brood. identified dives calculated index patch based time allocation dive assess patch. Results found penguin varied stages, became shorter progressed. Although lower improved season. Conclusions These results suggest strategies influenced both distribution, low due combination competition but compensated natural variation prey. Reduced trip durations towards end period an reproduction maximum energy demand late chick-rearing coincides with resource availability environment. This explain why Overall, our sheds light drivers colonial seabirds, important ecology.