Emigration in emperor penguins: Implications for interpretation of long-term studies

Site fidelity is an important evolutionary trait to understand, as misinterpretation of philopatric behavior could lead to confusion over the key drivers of population dynamics and the environmental or anthropogenic factors influencing populations. Our objective was to explore the hypothesis that emperor penguins are strictly philopatric using satellite imagery, counts from aerial photography, and literature reports on emperor penguin distributions. We found six instances over three years in which emperor penguins did not return to the same location to breed. We also report on one newly-discovered colony on the Antarctic Peninsula that may represent the relocation of penguins from the Dion Islands, recently confirmed as having been abandoned. Using evidence from aerial surveys and the historical literature, we suggest that emigration may have been partly responsible for the population decline at Pointe Géologie during the 1970s. Our study is the first to use remote sensing imagery to suggest that emperor penguins can and do move between, and establish new, colonies. Metapopulation dynamics of emperor penguins have not been previously considered and represent an exciting, and important, avenue for future research. Life history plasticity is increasingly being recognized as an important aspect of climate change adaptation, and in this regard our study offers new insight for the long-term future of emperor penguins.