Tuesday, August 11, 2009

The Problem with mice

This came through an email list I monitor, from Elton Smith, Conservation Manager of Orokonui Eco-Sanctuary.

The Problem with Mice

There is no best practice or standard operating procedure to eradicate or control mice

DoC does not intend to write a best practice. There is simply not enough data available

There is no way to predict the success or failure of mice eradications at an early stage – mice are almost impossible to detect at low levels.

38% of mouse eradications fail (5% Norway Rat).

50% of Brodifacoum operations fail in eradicating mice

50% of aerial operations fail to eradicate mice

The preferred habitat of mice is rank grass although in the absence of rats mice can be found in high densities in a wide range of habitats. Densities can reach 160 mice per hectare.

The mean home range of mice can be as little as 8-10m between April and July

A 50m grid is deemed to be too coarse (by some) to accurately detect mice at low levels. The recommended spacing is 10m. Who on earth has the resources to monitor at this rate?

Recent research has show that mice can cover large distances in very low numbers (500m +) and appear to be very trackable in tunnels

Live mice have been seen carried by kaka, morepork, weka and kingfisher.