Leopard Seal Predation of Adelie Penguins

Systematic observations on a beach at the Cape Crozier, Antarctica Adelie Penguin (Pygoscelis adeliae) rookery provided data on the effects and form of Leopard Seal (Hydruga leptonyx) predation on adult and young penguins. Active predation, involving up to four seals, was observed during 56% of the time with average kill rates of 0.61 birds/hr. Predation rates increased with the height of incomingwaves and also when landing penguins were encumbered by floating ice on the behcn. Time of day was not found to influence predation rates. When young penguins began their exodus from the rookery in Jan. seals no longer preyed on adults. Seasonal depredation from Leopard Seals on the Cape Crozier beaches approximates 5% of the breeding population. The predators are thought to be utilizing a temporary, but abundant food resource.