Predator Free pathways: Eradication – can we do it?

Department of Conservation —  13/03/2020

With the launch of the Predator Free 2050 strategy: ‘Towards a Predator Free New Zealand’, we’re doing a series of blogs about the pathways identified in the strategy which are going to help us get to Predator Free.

One of those pathways is toitū te mahi haepapa kīrearea – moving from sustained predator control to eradication. We look at the work of ZIP to remove predators and protect our special places.

The current predator control approach on mainland New Zealand is the suppression of predator populations using traps or toxins. Ongoing suppression always carries the risk of reinvasion and must be continually managed. 

New Zealand is a world leader in removing invasive predators from islands and predator fenced areas but creating mainland safe havens has historically relied on relatively small scale fenced sanctuaries to keep out invasive predators.


Enter Zero Invasive Predators Ltd (ZIP), a research and development entity, who are leading the way to remove possums, rats, and stoats from large mainland areas.

ZIP was established to develop operationally ready and innovative technologies that will help us create large areas free of possums, rats and stoats, and protect them from re-invasion. They call this model ‘Remove and Protect’.

A ZIP field ranger searches for a radio signal, Perth River valley. 📷: Chad Cottle

The Remove and Protect approach, if successful, will make it possible to:

• Carry out predator control in terrain where it is neither desirable nor possible to construct predator fences

• Reduce our dependence on the repeated wide scale application of toxins at chosen sites

• Enable progressive expansion of a protected area as funds and confidence allow

• Create an environment on the mainland where, in time, ecological integrity could rival that of predator-free offshore islands

The Remove and Protect approach is probably best suited to land areas bounded by geographic ‘barriers’ such as oceans, large rivers and alpine tops, making them relatively easy to defend once predators have been removed.

South Westland’s Perth Valley

ZIP, supported by DOC, Predator Free 2050 Limited and the NEXT Foundation, is currently developing the Remove and Protect approach in the 10,000 ha Perth Valley, South Westland. Last year they carried out an initial predator removal operation, using a modified application of aerial 1080, which succeeded in removing all stoats, and all but a very small number of individual possums and rats.

The Perth River Valley and Great Unknown beyond, hidden behind cloud. 📷: Chad Cottle

The challenge now for the ZIP team is to remove the remaining possums and rats before they re-establish within the valley, and then to protect the valley against reinvasion from outside.

The Perth River valley is surrounded by cold, fast-flowing rivers, and by Kā Tiritiri o te Moana (the Southern Alps). Previous research by ZIP suggests that these rivers will be strong barriers to reinvasion by both possums and rats (reinforced in places by kea-safe traps).

Some level of reinvasion is expected, and ZIP is using a highly sensitive network of lured cameras throughout the field site to alert the team to any predators that get in, so that they can quickly respond. ZIP is making exciting progress toward permanently protecting this spectacular place from the adverse impacts of possums, rats, and stoats – great news for our endangered native species!

Towards a Predator Free New Zealand

A future Aotearoa, flourishing with abundant native wildlife and forests is the bold vision that has galvanized thousands of New Zealanders into active support for a predator free New Zealand by 2050.

The Predator Free 2050 strategy, ‘Towards a Predator Free New Zealand’, sets out a framework over the next 30 years for New Zealand to address the current biodiversity crisis and achieve the predator free goal.

Find out more about ZIP:
Find our more about the Next Foundation:
Find out more about Predator Free 2050 Limited: