Pest removal


 The 14.5 km predator exclusion fence is currently under construction as a first step to remove all introduced mammalian pests from within the 671 hectare fenced area. Since trapping began in 2007, we have physically removed around 30,000 pests from the area we oversee by trapping and hunting. In winter 2016, the Sanctuary will close for approximately 12 months while pests are removed from inside the fenced area with an aerial bait drop process. 


Aerial bait drop 2016

The final stage in pest removal will be achieved by using an aerial drop of brodifacoum, a poison that is widely used for similar purposes and found in widely-used rodent control products available for purchase at most NZ supermarkets and home supply stores.

This follows a process identical to those followed by sites worldwide where, in every case, removing pests has led to a long term recovery of indigenous plant and fauna populations and ecosystems.

In New Zealand brodifacoum has been used successfully in rodent eradication programmes on offshore islands and within fenced mainland sites, such as Maungatautari Ecological Island in Waikato, Orokonui Eco-Sanctuary in Otago, and Tawharanui and Shakespear Regional Parks in Auckland.

We are following all guidelines for this procedure provided by the New Zealand Food Safety Authority, consultants and operators familiar with identical bait applications, and the manufacturer of brodifacoum. We are also following all conditions in the resource consent application and taking every precaution to ensure a well-managed, safe pest removal process for neighbouring residents, and volunteers and contractors performing the bait application.

In the event that there is a second consecutive year of beech mast (where heavy seeding occurs and pest food is abundant within the sanctuary), BWST may opt to alter its pest removal programme accordingly.

Project timeline

October 2015

Resource consent application for pest removal process filed with Nelson City Council.

November 2015

Nelson City Council determines the consent will have limited notification.

December 2015

Inform Nelson city community about pest removal process and plans.

March 2016 (estimate)

Resource consent granted.

May 2016 (estimate)

Pest-proof fence construction is completed.
Fence completion celebration event for the public.

June 2016 (estimate)

The Brook Waimarama Sanctuary closes temporarily to the public.

July - September 2016

Pest removal operation using aerially and hand dispersed brodifacoum. It is estimated that three aerial drops will be required. An experienced crew will undertake clean up and monitoring activities after each to ensure bait remains within the fenced area and waterways are protected.

We will publicly notify through local newspapers that aerial operations are planned and to be aware of helicopter noise and when the activity will begin.

September 2016 (estimate)

Captive kaka breeding programme begins in the aviary within the Sanctuary.

September 2016 - February 2017

Pest removal and mop-up plans are undertaken by experienced staff and volunteers. This means the land is monitored for any remaining living pests and, if any surviving populations are detected, traps and bait are deployed to the specific area(s).


The Brook Waimarama Sanctuary Trust re-introduces the first species into the Sanctuary, likely kaka and kiwi.

The Sanctuary opens as a new visitor attraction for the Nelson region.

More information

Do you have questions about the project? Read these questions and answers.