Corticosterone responses and body condition of penguins arriving at Cape Bird, Cape Royds and Cape Crozier, Ross Island. 2002-2003

With unusual ice conditions around Ross Island as a consequence of the iceberg B15 being stationary north of Ross Island, penguins returning to rookeries had much further to walk than usuall. The effects of distance walked on body condition and measures of stress in penguins arriving at three different breeding colonies including Cape Bird (25 - 30 km walk), Cape Royds (60 - 70 km walk) and Cape Crozier (0.5 km walk) was examined. Blood samples were collected from penguins arriving at each rookery. Birds were caught as they came ashore and single blood samples collected from a flipper vein. Each bird was placed in a mesh bag and further samples were collected 15 and 30 minutes after capture. Measurements of body weight and size were made before the birds were released. Blood samples were analysed for corticosterone concentrations. Heterophil/lymphocyte ratio counts were made as a measure of potential chronic affects of stress on the immune system. 110 birds blood was sampled at Cape Bird, 20 at Cape Royds and 20 at Cape Crozier.