Behaviour and diet of the Tasman parakeet (Cyanoramphus cookii) on Norfolk Island, South Pacific : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Conservation Biology, Massey University, Albany, New Zealand
Conservation of threatened species requires an understanding of their biology in the wild, including aspects of their dietary diversity, general behaviours and interactions with other species. For many threatened species however, obtaining even basic information about their biology in the wild proves challenging. This is because they often occur in small numbers, or in remote locations, limiting our ability to quantitatively describe behaviours. The Tasman parakeet (Cyanoramphus cookii) endemic to Norfolk Island, has experienced two cycles of critically low numbers in the last 40 years. Since the 1970s, the species is the subject of regular management, chiefly including introduced predator control and the provisioning and maintenance of predator-proof nests within the Norfolk Island National Park. These actions have resulted in population increases to approximately 400 individuals by 2018. As Tasman parakeets numbers increase, managers face challenges to target interventions that could help Tasman parakeets establish and reproduce as they disperses outside the National Park. In this thesis I examine the behaviour of Tasman parakeets and crimson rosellas (Platycercus elegans) during winter and spring to understand the response of both species to disturbance (presence of observers). I also examined the diversity of food species consumed by Tasman parakeets and crimson rosellas within and outside the boundaries of the National Park. During this research, Tasman parakeets were first sighted at shorter distances than crimson rosellas, furthermore, Tasman parakeets were observed at lower heights than crimson rosellas. Overall, these findings reinforce that Tasman parakeets are behaviourally more vulnerable to introduced predators than crimson rosellas, with further research required. I also determined that Tasman parakeets and crimson rosellas overlap in feeding resources and both species rely heavily on seeds of Norfolk pine (Araucaria heterophylla) during winter, however further examination of seed availability and potential competition is required.