abstract
Seasonal (within a breeding season) and year-to-year changes in the diets of the four species of penguins breeding at Marion Island are reviewed. King and gentoo penguins, which are resident at the island throughout the year, show seasonal changes in the relative proportions of different prey types (fish, cephalopods and crustaceans) consumed. However, the few available data suggest that prey species of king penguins vary little from year-to year, whereas those of gentoo penguins show some variation. In contrast to king and gentoo penguins, macaroni and rockhopper penguins show marked seasonal and annual variation in both the relative proportions of prey type consumed and the species composition-of their diets. Seasonal changes reflect changes in their foraging behaviour during chick-rearing, but year-to-year changes are probably related to hydrographic events, which are known to occur in the vicinity of the island and which alter prey species composition and availability.
