Traps are an essential component of the approach that Zero Invasive Predators Ltd (ZIP) is developing to help free the New Zealand mainland from possums, rats and stoats. We use traps to (i) defend predator-free areas from incursion by these predators, and also (ii) detect any individual animals that evade natural or virtual barriers (so that they can then be removed before successfully re-establishing a population in the area).

For projects where the goal is to completely remove predators, it’s essential that the traps used are highly effective – the project goal will never be achieved if too many individual predators can successfully evade the traps, because those predators may breed and establish a population.

It's also important that the kill traps we use are humane. The National Animal Welfare Advisory Committee (2011) guideline for assessing the welfare performance of kill traps[1]  provides a very good basis for doing this.

Greater Wellington Regional Council (Greater Wellington) intend to establish a trapping network on the Miramar Peninsula targeting stoats, using an animal welfare ‘approved’ trap, as part of the Predator Free Wellington project.  Consequently, in February 2019, Greater Wellington asked ZIP to test the animal welfare performance of the BT200 kill trap for stoats (Mustela erminea) against the NAWAC (2011) guideline.  The BT200 is a replica of the DOC200 kill trap, and is produced by National Springs and Wire Products NZ Ltd, who supported the testing.

We assessed the welfare performance of a trap comprising two BT200 kill traps housed within a wooden (treated pine) tunnel that contained wire-mesh baffles, during February and March 2019.

The methods, results and conclusions of this project are available here

We concluded that, for stoats, the BT200 kill trap, in a double set, double entrance ‘baffled’ wooden tunnel manufactured to the designs and dimensions used by Greater Wellington meets the NAWAC (2011) specification for acceptable killing effectiveness of a Class A kill trap. 

[1] https://www.mpi.govt.nz/documentvault/8521