Nest site selection by mohua and yellow‐crowned parakeets in beech forest in Fiordland, New Zealand

Abstract

Nest site selection in two hole‐nesting forest birds, mohua (yellowhead, Mohoua ochrocephala) and yellow‐crowned parakeet (Cyanoramphus auriceps), was investigated. Parakeets nested in a wide range of cavities ranging in size up to half a metre across. In contrast, mohua used small cavities that support the sides of their cup‐shaped nests. Most parakeet nests were found in red beech trees (Nothofagus fusca), which have many large cavities, and both species nested most often in trees >70 cm in diameter. Nest sites arc very numerous in our study area and are probably not limiting for either species in similar forests throughout Fiordland. However, neither species is likely to be able to nest in beech forests managed for timber production, in which most trees will be large enough for nesting only just before they are harvested. Although long‐tailed cuckoos (Euclynamvs taitensis) parasitise mohua nests and prey upon their nestlings, most mohua nest holes arc too small for cuckoos to lay eggs in. High nests of both species are less likely to be preyed upon by stoats than low ones. Neither species shows adaptive preferences for small nest holes or high nest sites. This paper presents a novel way to analyse the use of nesting cavities using capture‐recapture analysis.