Rock wren/tuke

Image: DOC

Introduction

Rock wren raised up to five times more chicks after 1080 treatment than without.

Highlights

This small reclusive bird survives in pockets in the South Island alpine zone.

Rock wren nest on the ground so are easy prey for stoats and other predators. 

Without more widespread pest control rock wren are at risk of dying out.

Studying how this bird responds to aerial 1080 predator control is a high priority for our scientists.

1080 treatment boosts nesting success

We monitored rock wren in the Grange Range, Lake Aorere and Shelter Rock Basin areas of Kahurangi National Park between 2014 and 2017. There were two separate 1080 treatments in 2014/15 and 2016/17. Our researchers tracked nesting in areas with 1080 and without.

The birds in the 1080 areas raised three times more chicks than birds in the non-treatment area, monitoring over the first breeding season showed.

The benefits continued when the birds bred again a year later. That season rock wren produced five times more offspring than the birds in the comparison area.

Without 1080 treatment high stoat levels wipe out most nests and kill adult birds.

In 2016, a return to the study area where 1080 was not used found the rock wren population had dropped from 25 birds in 2014 to just two birds. To avoid losing this population altogether the area was treated with 1080. These birds are now on the increase. 

Further monitoring in 2016 showed nesting success in the 1080 treated areas was also much higher than in untreated areas in previous years.

Rock wren nesting success bar graph.

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Rock wren predation bar graph.

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Snow storms also affect these alpine birds

In 2014, 22 monitored rock wren disappeared after unseasonably heavy spring snow following 1080 pest control. The high nesting success more than made up for these lost birds. However, questions remained about what happened to them.

Further research has confirmed that rock wren abandon nests and sometimes die following snow storms in areas where 1080 was not used. This shows that weather events are one of the challenges this alpine specialist must contend with.

Other monitoring results

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