Predation of Short-tailed Shearwater Eggs on Great Dog Island, Tasmania

Abstract

Evidence of predation by Blotched Blue-tongue Lizards Tiliqua nigrolutea and Water-rats Hydromys chrysogaster on Short-tailed Shearwater Ardenna tenuirostris eggs was obtained during the 2006–07 breeding season on Great Dog Island, Tasmania. Overall, 120 burrows were monitored across the entire incubation period, with 8.3% of eggs being eaten. Predation occurred throughout the incubation period, with the highest numbers being taken during December. In 90% of cases, eggs were taken when left unattended in the burrow. These figures are minima, since Water-rats were also suspected of being the cause of egg predation between observation visits. Predation at this level may not significantly affect the island’s population of Short-tailed Shearwaters.