The role of giant petrels in the Southern Ocean ecosystem.

Abstract

Giant petrels are the dominant scavenging seabird species in the Sub-Antarctic and maritime Antarctic ecosystems. They consume large amounts of penguin carrion, but also include significant numbers of seals, Antarctic krill Euphausia superba, and small petrels in their diets. Differences in energy requirements between northern giant petrel Macronectes halli and southern giant petrel M. giganteus, and between male and female chicks, are demonstrated. The present world breeding population is concluded to be c8600 pairs of M. halli and c38 000 pairs of M. giganteus. Total world non-breeding populations of 26 000 and 113 000 birds are calculated for M. halli and M. giganteus, respectively. The energy consumption of these populations in the breeding season is assessed and, taking into account geographical variation in diet their impact on local ecosystems is evaluated. -from Author