29 Nov 2015

Rat plague crisis about to hit New Zealand says BirdLife Partner Forest & Bird

A rat attacks a keruru egg
A rat in a kererū egg (Photo by Nga Manu).
By Kimberley Collins

BirdLife New Zealand partner, Forest & Bird is predicting a pest plague next winter and spring given the significant level of beech flowering occurring now.   “An abundance of beech spring flowering will translate into an abundance of seed next autumn, known as “masting”, which in turn leads to an eruption of rat and stoat predator populations,” says Forest & Bird advocate Kevin Hackwell.  When seed supplies run out these predators turn on endangered birds such as mōhua, kākā, kea, whio and kiwi along with other at risk species like bats and land snails.

This occurrence is a worldwide phenomenon but in New Zealand it is particularly significant given the ability of the invasive predators to prey on New Zealand’s indigenous species.  Previous mast years have led to massive decreases in populations of previously widespread birds like mōhua.

This will be the second mast year in a row with the last one occurring in 2014.  In response to that the Department of Conservation (DOC) launched the `Battle for the Birds’ which was judged a big success.  Between August 2014 and February 2015, DOC staff planned and carried out an unprecedented 27 aerial pest control operations over more than 600,000 hectares in priority areas across the South Island to protect native species from the forecast predator plagues. In addition, six North Island operations covered more than 94,000 hectares.  Field monitoring results showing rat numbers crashing to undetectable or very low levels at most sites, and stoat plagues were averted.  Monitoring of robin, rifleman, mohua and rock wren showed good nesting and survival rates.

But this high level of control was achieved by the Department of Conservation allocating significant funds towards pest control by delaying other work including delaying staff appointments.  Forest & Bird is concerned that the necessary funding for a second `battle' will not be able to found by savings on other projects this year, 

Department of Conservation monitoring has confirmed the widespread occurrence of abundant beech flowering.  Mr Hackwell says a pest plague will threaten many of our endangered and threatened species, and set back crucial protection and restoration work for our native species.

“It is crucial that the Government urgently commits to emergency funding for substantial pest control, so that the Department of Conservation can begin the planning of a comprehensive response right now” said Mr Hackwell.

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