Using artificial nests to explore predation by introduced predators inhabiting alpine areas in New Zealand

Abstract

Many bird species endemic to alpine New Zealand are now at critically low densities and restricted in range, making predator‐prey research difficult. We used artificial nests in the Borland Valley, Fiordland National Park, to investigate (1) which introduced species is the most frequent nest predator in the two habitats, (2) whether nest survival differs between habitats, and (3) the utility of artificial nests for guiding conservation management. We used different types of artificial nest in 2 different years and undertook a calibration study of the two types. In 2003, survival of artificial nests containing wax eggs and chicken eggs was high in both habitats. In 2004, survival of artificial nests containing plastilina eggs and chicken eggs was low in both habitats, but was higher in alpine grassland compared with beech forest. Stoats and possums were the most frequent predators (36 and 22% respectively of artificial plastilina nests in alpine grassland and high‐altitude beech forest combined); these percentages did not vary significantly between habitats. Given the low density and sparse distribution of vulnerable species in much of New Zealand, data from artificial nests can be a useful tool for studying predation in these remote and difficult habitats, or at least, preferable to ignorance. However, the type of artificial nest used can strongly affect the rate at which they are destroyed.