The foraging range of Little Penguins (Eudyptula minor) during winter

Abstract

Although the movements of seabirds at sea during various stages of breeding in spring and summer have been the focus of many studies in recent years, there is still little known about the non-breeding period for most species. Satellite telemetry was used to determine the at-sea movements and foraging range of 47 Little Penguins (Eudyptula minor) from Phillip Island, south-eastern Australia, during the winter non-breeding period. Individuals conducting single-day trips (72% of individuals) typically foraged 8–14 km from the colony, whereas individuals conducting longer trips (28%; 2–49 days) foraged either within Port Phillip Bay or in the coastal waters of western Bass Strait at maximum distances of 62–147km from the colony. Although there was no difference between sexes in duration of foraging trips, the overall foraging range of males (841 km2) was substantially smaller than that of females (1983 km2) across all months, and showed an overlap of only 34%. Our results show that the foraging range of Little Penguins in the non-breeding period is greater than that observed during the summer breeding period, which suggest a reduction in local food abundance in winter and highlights the importance of foraging areas distant to the colony during a time of increased energetic costs and higher mortality.