Large-scale habitat selection by parrots in New Caledonia

Abstract

Habitat studies are important for conservation, particularly for parrots, as many are threatened and their ecological requirements are often poorly known. Our aim was to contribute to the conservation of parrots in New Caledonia by examining their selection of habitat at a large scale. From 2002 to 2010, we documented 1,357 encounters with New Caledonian Parakeets (Cyanoramphus saisseti), Horned Parakeets (Eunymphicus cornutus), and New Caledonian Rainbow Lorikeets (Trichoglossus haematodus deplanchii) throughout mainland New Caledonia. We used GIS to infer habitat selection in relation to vegetation, forest cover, forest size, altitude, rainfall, and soil. New Caledonian Parakeets selected forested areas with oligotrophic soils, particularly those from ultramafic substrates. Horned Parakeets selected habitats with a high proportion of rainforest, as well as oligotrophic soils on metamorphic substrates, yet soil fertility was less important for them. Both parakeet species favoured large forests, and appeared to avoid areas with low forest cover. Altitude had a relatively minor influence upon habitat selection by parakeets. Rainbow Lorikeets favoured areas at low altitudes with minimal rainfall and mesotrophic soils, although they were not influenced by soil fertility to the same degree as the parakeets. We consider rainforests on oligotrophic soils at intermediate altitudes (200–800 m) to be most important for parrot conservation in New Caledonia, as these habitats are likely to support significant parakeet populations.