Adélie penguin diet and climate change during the middle to late Holocene in northern Marguerite Bay, Antarctic Peninsula

We investigated one active and three abandoned Adélie penguin (Pygoscelis adeliae) colonies in northern Marguerite Bay, Antarctic Peninsula, during austral summer 2000. Extinct colonies were located by ground survey on small islands and recognized by concentrations of nest pebbles. The colonies were excavated to recover organic remains from ornithogenic soils. Radiocarbon dates on penguin bone and eggshell provided a 6,000-year occupation history after correction for the marine-carbon reservoir effect; this history was compared to the paleoclimate record (ice cores and marine sediments) to assess patterns in occupation by penguins with episodes of climate change. We quantified prey remains recovered from the sites to examine potential dietary shifts by penguins with climatic change. Two species, Antarctic silverfish (Pleuragramma antarcticum) and squid (Psychroteuthis glacialis), were most commonly represented in the sediments. The data indicate that silverfish may have been exploited more during cool, and squid in warm climatic intervals in the past.