The movements of gentoo penguins Pygoscelis papua from Ardley Island, Antarctica

The movements of gentoo penguins (Pygoscelis papua) in Antarctica were studied by equipping a total of 37 birds captured at Ardley Island, South Shetlands between December 1991 and May 1996 with position-determining devices. Information on area usage was derived from 20 of these devices and covered the incubation period (N = 3 birds), the chick-rearing period (N = 14 birds) and the over-wintering period (N = 3 birds). During incubation birds only ventured further than 50 km from the colony 20% of the time and no individual ranged further than 200 km from the colony. In contrast, no individuals attending chicks ranged further than 16 km from the colony. During winter the maximum distance ranged from the colony was 268 km. Mean distances between the birds and the colony were 80, 81 and 127 km. Individual birds tended to associate with one spot, making short (10 day) forays away before returning to nodal areas. The ranging capacity of gentoo penguins appears considerably less than that of sympatric congeners and may reflect the ability of gentoo penguins to dive deeper and thus exploit prey not accessible to congeners.