An overview of mainland control efforts of ship rats, stoats and possums – the most significant predators in the mainland forests of New Zealand.


Ship rats (Rattus rattus), stoats (Mustela erminea) and possums (Trichosurus vulpecula) are the most significant predators in the mainland forests of New Zealand. These mammals were first introduced to New Zealand in the 1800s and have had a large impact on our native fauna ever since, being implicated in the extinction of at least nine bird species.

Over the past 30 years, attempts have been made to control these pests both on offshore islands and, more ambitiously, on the mainland, with varying success.

In this report, we provide an overview of mainland control efforts.

  • We assess the historic and current impacts of these three species on native wildlife in New Zealand. 
  • We discuss the types of control that are currently available and consider under which circumstances each is of most use. 
  • We then consider what pest control has achieved to date, both in terms of reducing the abundance of pest species and increasing the abundance of our native fauna. 
  • Finally, we discuss what we have learned from pest control efforts to date and use this information to formulate some recommendations for future research and management in this field. 

It is hoped that by collating this information, we will provide pest control managers and practitioners with better insight into ways to improve and optimise control efforts in the future

Publication information

Published by the Department of Conservation

Written by Kerry Brown, Graeme Elliott, John Innes and Josh Kemp, 36 p 

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