Predators and the decline of New Zealand forest birds: An introduction to the hole‐nesting bird and predator programme

Abstract

The role of predators in the decline of New Zealand forest birds, and specifically the roles of mustelids and rodents, is reviewed. Hole‐nesting forest birds are particularly vulnerable to predation because they display few predator‐avoidance behaviours. Mohua (Molnia ochrocephala) and parakeets are especially at risk because they nest when stoat (Mustela erminea) numbers in the forest are highest, and, because only females incubate, nest predation causes a biassed sex ratio. The Department of Conservation's hole‐nesting birds and predator research programme aims to investigate three questions: (1) Are contemporary predators still having a significant impact on the long‐term viability of forest bird populations? (2) Can we predict when predators will affect forest bird populations? (3) Can we increase the productivity and viability of forest bird populations by controlling predators? Mohua and yellow‐crowned parakeets were used as indicator species to answer these questions, and the resulting eight studies are briefly outlined.

Key words:

• predators
• forest birds
• hole‐nesting birds
• indicator species
• mohua
• yellowhead
• Mohua ochrocephala
• yellow‐crowned parakeet
• Cvano‐ramphus auriceps
• stoats
• Mustela erminea
• rats
• Rattus sp.