The emperor penguin dives deeper and longer, fasts longer, and endures the harshest weather conditions of all diving birds. It spends about four and half months per annum deep in Antarctic pack ice away from shore and stations, and thus is largely unavailable for study. This time includes preparation for the molt, and travel to the colony to breed, a time period in which great swings in body weight occur. This study will fill an important gap in what we know about the biology of the annual cycle of the emperor by examining the molt-post molt period. The P.I. proposes to traverse the Amundsen and Bellingshausen seas on the Oden, to locate and tag emperor penguins during the molt season. The objectives are to (1) Place satellite tags on 20 adult post molt birds to determine their route, rate of travel, and diving behavior as they return back to their breeding colonies, (2) Obtain an index of body condition, (3) Collect guano to determine the type of food consumed by emperor penguins in the region, (4) Conduct shipboard surveys to sight and plot the location and abundance of adult and juvenile birds on the ship's track. The PI hypothesizes that bird dives will be shallow during the initial post-molt phase, and that food will consist primarily of krill; that there will be differential dispersal of birds from the Ross Sea vs. Marie Byrd Land, with Ross Sea birds traveling farther; and that the greatest adult mortality occurs during the molt and early post molt period. Broader impacts include training of a post doc, a graduate student, and an aquarium volunteer. The P.I. also will present findings through a website, through public lectures, and in collaboration with the Birch aquarium.