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April 2019 Issue
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Feeding kea tahr may prevent 1080 deaths

Distracting kea with a tahr carcass may help prevent bird deaths during aerial 1080 operations. Photo: ZIP

A new method has been developed to prevent kea being poisoned during 1080 operations by using the birds’ fondness for tahr meat.

Kea are among the few native birds that have been inadvertently poisoned by 1080, but so far efforts to prevent them from eating the poisoned bait have had limited success.

DOC has monitored nearly 200 kea during 1080 operations and about 10 per cent of the birds have been killed due to eating the poisoned pellets. While the number of birds killed is far outweighed by the breeding success following a 1080 drop, the death of endangered native birds has been contentious.

DOC has tried using the bird repellents anthraquinone, which makes kea feel ill, and d-pulegone, which has an odour that kea dislike, but both have had significant drawbacks in trials. Anthraquinone also deters rats, reducing the efficacy of the poison, while d-pulegone has proved difficult to store and manufacture in pellet form.

But Zero Invasive Predators (ZIP), a partnership between DOC, the Next Foundation and other conservation groups, believes it has found a solution.

ZIP is planning a 1080 drop in the Perth River Valley on the West Coast in April as part of an attempt to permanently eradicate possums and possibly rats from the valley.

It had planned a 1080 drop last year, but monitoring found some kea had been eating non-toxic pre-feed pellets dropped in the area, which led to DOC reconsidering whether the operation should go ahead. ZIP also planned to drop pellets at twice the normal density, increasing the risk to kea. The operation was subsequently postponed, but due to heavy snow.

Since then, ZIP has been researching using tahr carcasses to attract kea away from drop zones. The carcasses, culled from existing herds in the valley, were placed above the bushline next to buckets of anthraquinone pellets.

Using remote cameras, ZIP found kea flocked to eat the tahr, picking them clean within a week, and they also ate the pellets. Because few rats venture into alpine areas, they aren’t put off the pellets, but kea learn not to eat them.
ZIP has also been feeding kea anthraquinone-laced pellets in captivity and found kea do avoid the pellets after being exposed to the repellent.

DOC has now given the 1080 operation the green light.

“There’s no doubt that this operation poses a risk to the kea in the valley, but I’m satisfied that use of the bird repellent to train kea to avoid baits, and tahr carcasses to attract kea away from baits, will help to mitigate these risks,” said Mark Davies, DOC West Coast director.

Overall, Davies said kea are generally at low risk of being poisoned, but the risk increases near tourist sites where they have learned to eat human food.

“This is why it is really important not to feed kea, or allow them to gain access to foods such as what they might find in a compost heap or rubbish bin,” he said.

ZIP will monitor about 18 kea using radio transmitters to see if the methods are effective and will report the results prior to a second planned 1080 drop four to six weeks later.