Spatial ecology and conservation of parrots in New Caledonia

Abstract

New Caledonia’s parrots face a variety of threats, and the populations of several species appear to be in decline. However, it is difficult to determine the cause or extent of their declines due to a scarcity of ecological data. Accordingly, this research aims to contribute to the conservation of parrots in New Caledonia by studying their spatial ecology. This thesis documents the habitat preferences of parrots on the main island of New Caledonia in relation to environmental variables on a large and small scale. Information about their activity patterns and flock sizes is provided, and an optimised method of surveying parrots is described. In addition, ecological niche models are used to infer the distribution and population size of parakeets. New Caledonian Rainbow Lorikeets (Trichoglossus haematodus deplanchii) were frequently encountered in this study, and were successful in a variety of habitats, including urban areas. New Caledonian Parakeets (Cyanoramphus saisseti) and Horned Parakeets (Eunymphicus cornutus) were less common, and appeared to be more specialised in their habitat requirements. Relatively large and intact patches of rainforest on oligotrophic soils at intermediate altitudes provided important habitat for both of these species, and would be appropriate areas for conservation given their vulnerability to mining activities. New Caledonian Parakeets foraged mainly at low canopy heights, and were regularly observed at the edge of forest, in slope forest, or in maquis (shrubland). In comparison, Horned Parakeets tended to forage at greater heights, favoured valley forest over slope forest, and avoided open habitats. The observed patterns of vertical stratification and habitat segregation probably help to prevent interspecific competition. Flocks of parakeets usually consisted of one or two birds, and their size remained relatively consistent during the day, and throughout the year. Most Rainbow Lorikeet flocks contained only a few individuals, though some had up to 40 birds. All species had bimodal activity patterns. Distance sampling was found to be suitable for surveying parakeets in New Caledonia, but surveys should be standardised to facilitate comparison between different areas and time periods.Parakeets in New Caledonia appear to have small populations, and their distributions are expected to contract as a result of climate change. Ouvéa Parakeets (Eunymphicus uvaeensis) may be particularly vulnerable in this regard. This study indicates that the current reserve network provides insucient protection for parakeets. There is a need to increase the area devoted to reserves, provide corridors for dispersal, manage introduced species, and raise environmental awareness in the region.