A Massey University postmortem has found six kea in the Matukituki Valley of Aspiring National Park "are likely'' to have died last month from 1080 toxin intended for rats and stoats.
Doc threats director Amber Bill said yesterday Doc was considering "aversion techniques" trialled in the Perth Valley in South Westland last year.
The trials used a non-toxic aversion bait containing the bird repellent anthraquinone "with some success", Ms Bill said.
"However, these methods would need more research before Doc could use them in standard predator control operations.
"Doc has previously done some work to develop a repellent for kea but a major challenge is that use of repellant in cereal baits can also cause predators to avoid baits."
Ms Bill said it was "upsetting" and disappointing" to lose the six kea but Doc was confident control of rats and stoats would "significantly boost nesting success and the number of young birds entering the population".
It believed the dead kea were more at risk because they had learned to scrounge for food from trampers, and Ms Bill said an education campaign to discourage trampers from feeding kea was being considered.
Recent rodent monitoring results from the Matukituki Valley showed rats had been reduced from damaging levels — present in 47% of tracking tunnels — to being undetectable — 0% of tracking tunnels — following the 1080 operation.
An opponent of 1080 use, Cherilyn Walthew, of Lake Hawea, predicted yesterday rat numbers would increase rapidly after the poisoning programme because they had young every six weeks.
Ms Walthew said the kea deaths were "very disappointing ... heart-breaking, really" but "so not surprising".
"This is one of the most toxic poisons known to man.
"It poisons everything; everything dies, the insects, everything, even fantails."
The poisoning programme was designed to protect rock wren, kea and whio, as well as kakariki, kaka, and South Island robin.
The dead birds were three adult males, one adult female, one juvenile male and one juvenile female.
