Breeding And Overwintering Ecology Of Shy Albatrosses In Southern Australia: Year-Round Patterns Of Colony Attendance And Foraging-Trip Durations

We used radio-transmitters to study year-round patterns of colony attendance and foraging trip duration of Shy Albatrosses (Thalassarche cauta) at Albatross Island (1995-1997) and Pedra Branca (1997), Tasmania, Australia. Colony activity was largely diurnal, and foraging trip, incubation, and brooding shift durations were relatively short throughout the breeding season, consistent with foraging just a few hundred kilometers from the colonies. Shift durations decreased from 2.9 days early in incubation to an average of 24 hr during brooding. Foraging trip durations were similarly short in the first month postbrooding, but then doubled thereafter to approximately 2 days. Attendance and foraging-trip characteristics were similar between years and at both breeding sites. Both early in incubation and late in chick-rearing, females tended to undertake longer foraging trips than males. There was also an increased probability of failure if females spent as much time on the nest as males during incubation. Outside the breeding season, adults were relatively sedentary. Successful parents from Albatross Island forage off southeast Australia for just nine weeks before returning to spend much of the nonbreeding period attending the colony. The close proximity of the feeding and breeding grounds and near year-round presence of adults at the colony reflects locally favorable foraging conditions. Operating within this environment, Shy Albatrosses exhibit breeding, foraging, and provisioning characteristics that represent an extreme within the Diomedeidae.