King penguins on the Crozet archipelago in the southern Indian Ocean travel south to forage for food around the Antarctic Polar Front, where cold Antarctic waters meet warmer sub-Antarctic seas (pictured, a king penguin diving). Writing in Nature Communications, Bost et al. report that climatic variability can alter the birds' foraging behaviour and population dynamics (C. A. Bost et al. Nature Commun. http://dx.doi.org/10.1038/ncomms9220; 2015).

Credit: Antoine Joris

By tracking king penguins (Aptenodytes patagonicus) for 16 years, Bost et al. found that changes associated with an increased sea surface temperature of just 1 oC pushed the polar front southward, and increased both the distances penguins travelled to forage and the depths to which they dived for food. After large-scale climatic anomalies, their population size also fell. Climate models predict that the front will continue to shift southward, which may threaten penguins and their prey. Footnote 1