In this presentation, Dr. Steven Emslie will present new discoveries on the paleohistory of Adelie Penguins in the Ross Sea. Both bulk and compound-specific stable isotope analyses are applied to investigate population movements and dietary shifts of penguins throughout the Holocene, especially during a climatic event that occurred at ~2000 B.P. At that time, Adelie penguins shifted their colonies from the southern to the northern Ross Sea, resulting in a large 'supercolony' at Cape Adare. In addition, a new analysis of penguin mummies that date from over 45, 000 years old to the present provide information on stable isotopes in multiple tissues (skin, feather, bone, and toenail) for the first time in an avian species.