Seasonal, geographical, and age-related variations in the diet of the yellow-eyed penguin (Megadyptes antipodes)

Abstract

A quantitative study of yellow-eyed penguin diet was carried outattwomainlandbreeding areas over a 2-year period, and at five other breeding areas over shorter time periods. Yellow-eyed penguins (Megadyptes antipodes) ate 26prey species, with fish comprising 87% of the weight and 91% of the total number of prey items. Sprat occurred in the largest number of stomachs (70%) with red cod, opalfish, and squid in 49%, 42%, and 46%, respectively. Most prey items were <200 mm long. Prey were mainly pelagic species but also demersal species. The absence of inshore species in the diet and the distributions of prey species indicated that penguins travel away from the coast before beginning to feed, but remain over the continental shelf. Juvenile penguins ate more squid and less fish than adults, and weighed less. Differences in diet composition, body weights, and meal sizes were found between birds from different breeding areas, and between breeding seasons of contrasting reproductive success. Evidence from preferred prey and daily foraging patterns suggested that yellow-eyed penguins are selective feeders, and as such, are vulnerable to fluctuations in populations of their preferred prey. © 1990 Taylor & Francis Group, LLC.