Chlorinated hydrocarbons and trace elements in eggs of South polar skua and Adelie penguin

Bird eggs provide useful information about pollutant residues at feeding sites, but can reflect levels of contamination over a wider area. As top predators in marine systems, skuas (Catharactidae) are ideal species through which to monitor trends in oceanic pollution (Furness 1987). South Polar Skuas (Catharacta maccormicki) are especially interesting in this regard as they have one of the iargest annual migrations of any bkd. Moreover, they breed in what is arguably the cleanest place on earth, so that it is unlikely that the bulk of residues they contain are loca,l in origin. We analysed the eggs of South Polar Skuas breeding on Ross Island, Antarctica, for residues of chlorinated hydrocarbons, heayy metals and trace elements. As a control, a sympatric population of the Adelie Penguins (,$,goscelis adeliae), a species that does not range north of the Antarctic convergence, was tested for simiiar residues