Used to control a range of pests including possums, rats and stoats, 1080 is mixed into bait in an attempt to control pest numbers and help preserve native species. However, DoC information on 1080 acknowledges some birds - including kea and weka - are also attracted to the baits and can die as a result of eating them.
Josh Kemp, DoC science adviser, says the kea deaths are regrettable and represent "accidental bykill" from 1080 drops.
However, Kemp says controlling predators must take priority in order to prevent further decline in numbers.
"In total DoC monitored kea on 199 occasions spread over 14 aerial 1080 operations between 2008 and 2014, and 24 deaths were recorded," Kemp said.
"Deaths were recorded at only six of the pest control sites, which suggests that kea are at risk of poisoning at some sites but not others. The data strongly indicates that kea living in the mountains surrounding populated or high visitor areas are at higher risk of 1080 poisoning due to greater exposure to human activity and food.
"Monitoring shows that kea survive better and produce more young in the absence of predators after aerial 1080 than without it."
Experienced 1080 researcher Dave Hansford says available evidence suggests the benefit of 1080 to kea outweighs the numbers of birds accidentally killed.
However, Hansford said no poisoning of an endangered animal is acceptable and better alternatives need investigating, including different forms of poison and baits which repel birds instead of attracting them.
"Two dozen birds since 2008 ... with a threatened species, no casualty is acceptable," Hansford said.
"That's out of 199 that have been radio tagged - about 12 per cent mortality.
"People must understand you are not doing kea any kindness by feeding them. They're used to treating pretty much any found object as food and are much more inclined to investigate a 1080 bait.
"There was a trial of coating 1080 baits with a bird repellent, unfortunately that trial was a bit of a failure but the jury's out as to why. It's possible the formulation may not have been correct. There's still an opportunity to continue research with repellent.
"The third prong is a new generation of stoat-specific toxin and it won't kill kea. It's registered for field trials and it may be that's a more appropriate toxin above the tree line where you would expect to find kea."
A spokeswoman confirmed DoC is in the early stage of trialling alternative poisons to 1080 in order to target stoats and feral cats, but it does not yet have any research on the susceptibility of kea.
