Feeding Preferences of the Magellanic Penguin over Its Breeding Range in Argentina

Abstract

-The diet of Magellanic Penguins (Spheniscus magellanicus) was studied by stomach-pumping birds at five colonies (San Lorenzo, Punta Clara, Punta Loberia, Monte Leon and Punta Dungeness) over the species' latitudinal range in Argentina. A total of 159 birds were sampled during the period February 1986 to December 1988. Most prey items consisted of pelagic school fish, although squid and shrimps were also taken. At any one colony, birds appeared to be principally monoor bi-phagic and there were clear latitudinal differences in prey taken. Penguins in the northern colonies at San Lorenzo, Punta Clara and Punta Loberia consumed primarily anchovy (Engraulis anchoita) while birds at the two southerly colonies of Monte Leon and Punta Dungeness fed primarily on squid (Loligo spp. and Illex spp.), sprats (Sprattusfuegensis) and Hagfish (Myxine spp.). The strict dependence of Magellanic Penguins on commercially-exploited, schooling prey species makes the species particularly susceptible to changes in prey stocks, as has happened to congeners elsewhere that have suffered population crashes due to poorly-managed fisheries. Received iiJanuaryl 999, accepted 24 February 1999.