Long-Term Stability and Human Impact in Antarctic Skuas and Adélie Penguins

Abstract

This chapter assesses the impact of human activity associated with a field station on the long-term population stability of Adelie penguins (Pygoscelis adeliae) and Antarctic sku as (Catharacta maccormicki) at the Northern Colony, Cape Bird, Ross Island (77 0 13' S, 166 0 28' E). The field station has been occupied over 22 years at this site. Human impact was assessed by comparing an area of the colony near the station with a second one at a distance which was much less disturbed. Skuas appeared largely unaffected by the station with breeding density and pattern of territories little changed from first years of research here. Breeding success and age structure of the populations in the two areas were similar. The skuas maintained their high tolerance of people intruding into the territory that had been developed in the first years of the station's operation. This tolerance has persisted even though nearly all the original breeding birds have been replaced. The stability recorded in the skuas contrasts with the local impact found on the breeding penguins. Breeding groups nearest the station declined in numbers even though the total population of the colony markedly increased.