More work needed on kea repellent

Date:  21 August 2013

The Department of Conservation will continue to investigate ways to protect kea during 1080 operations after disappointing results from a recently tested bird repellent. 

Research shows that pest control using 1080 benefits kea and other birds by improving nesting success and survival of adult females.  However, kea are particularly inquisitive and DOC is researching ways to minimise the loss of individual kea in 1080 operations. 

The first field study using a bird repellent in an aerial 1080 operation near Arthur’s Pass earlier this month has resulted in five confirmed kea deaths out of 39 monitored birds.  

DOC Technical Advisor Threats, Michelle Crowell, said, “Losing five birds is naturally disappointing but overall the benefits to kea populations from pest control continue to outweigh the loss of individual birds to 1080.” 

“The repellent d-pulegone used in the 1080 operation showed promise in previous trials but was not effective enough to prevent kea deaths in this field operation,” said Dr Crowell. 

“We are obviously disappointed with the results so far, and once all the data has been fully analysed we will review our options, which include increasing the repellent concentration and investigating other repellents.” 

Analysis of the baits has shown that the repellent was less than the target concentration and further work was needed to account for dissipation during bait storage, said Dr Crowell.

The repellent was used in the DOC pest control operation over 10,619 ha around Otira as well as a nearby TBfree New Zealand operation over 10,130 ha at Taipo undertaken from 26 June to 1 August.  The Otira operation was aimed at controlling possums to protect forest health, as well as rats and stoats, to benefit native birds.

DOC has been working with the Kea Conservation Trust, TBfree New Zealand and Landcare Research over a number of years to develop a repellent to prevent kea deaths during aerial 1080 operations.   This has included research trials in pens, aviaries and field sites to test whether the repellents work, are safe and don’t affect possum and rat control.  The current research is funded by DOC, TBfree New Zealand and MBIE (Ministry of Business, Innovation and Employment). 

A new baiting protocol was introduced in 2010 to reduce the risk to kea, which included using less palatable baits and avoiding open areas above the bush line.

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Background information

DOC is investigating two bird repellents—d-pulegone and 9, 10 anthraquinone—for use in 1080 operations.  Both compounds have been trialled with other birds in New Zealand and overseas. 

D-pulegone is a food additive based on the peppermint flavour found in some plants in the mint family.  Birds have been shown to be irritated by its odour and taste.  The Environmental Protection Authority has confirmed that non-toxic pre-feed baits containing d-pulegone are not hazardous and that this compound does not change the hazard profile of 1080 cereal baits. 

9, 10 anthraquinone is found in plants and insects and causes gastro-intestinal irritation to birds.  

Since 2008, 155 kea have been monitored through ten 1080 operations with 20 (12.9%) recorded fatalities. 

Recent research at Okarito showed that following the 1080 pest control operation in 2011 kea nesting success in the treated area increased from 51% to 100%. Nesting success of 38% was recorded in a nearby untreated area.  The following year 69% of nests in the treated area succeeded, compared to 1% in the untreated area.  The Kea Conservation Trust is carrying out similar nest monitoring at Otira. 

1080 has been used in pest control in the Otira area since 1964 with seven operations using aerially sown 1080 cereal baits between 1989 and 2013. There is a sizeable kea population in this area. 

The kea population throughout the South Island is unknown but estimated at 1000-5000. Kea are classified as Nationally Endangered.

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