The Diet of the Rockhopper Penguin Eudyptes chrysocome at Macquarie Island

Abstract

The diet of Rockhopper Penguins at Macquarie Island was investigated during the 1984-85 breeding season. Adult euphausiid crustaceans constituted 98% of all the food items consumed and 70% of the total food mass. Euphausia valentini was the principal euphausiid species. Both pelagic and inshore fish species were also found in the diet, the most common of which was juvenile oceanic Krefftichthys anderssoni. The amount and composition of food brought ashore varied throughout the breeding season. Euphausia valentini was eaten almost exclusively in the pre-laying and late incubation periods. More fish were eaten duringyhe chick-rearing time, although E. valentini remained dominant in all weeks. Comparisons with data from diet studies at the Falkland Islands and Marion Island reveal that euphausiids are the principal food of the Penguins throughout their range. The species taken varies from site to site, probably reflecting local differences in prey abundance and distribution.