Fiordland kaka make "phenomenal" comeback
The Department of Conservation is attributing a spike in Fiordland's kaka population to a decade of pest control, including 1080 drops.
A population sample taken in the Waitutu Forest in December last year shows female kaka numbers are increasing, and young birds on the rise again.
The last population sample was taken by department scientist Terry Greene in 2005-2007 which found male kaka outnumbered females by six to one, and no juveniles were seen or caught.
Greene, who also carried out December's population sample, discovered the proportion of female kaka had increased almost four-fold, so the margin had dropped to about 1.7 times more males than females.
Not only were the adults flourishing, but 20 juvenile birds were caught, as well as many fledglings seen.
Greene described the result as "phenomenal".
"We knew that kaka were recovering but to find such strong evidence was hugely satisfying."
The Waitutu kaka study involved the capture and release of up to 120 kaka in 2005-2007 and in 2016.
The South Island sub-species of kaka is found from Nelson down the West Coast to Fiordland and Stewart Island but is classed as nationally vulnerable because of loss of habitat and threats.
In the mid 2000s the kaka population in Waitutu Forest was being ravaged by stoats and possums with female birds and chicks the prime victims as they nested in tree cavities.
Pest control at Waitutu Forest, in Fiordland National Park, has included localised trapping and poisoning and three treatments of aerially-applied 1080 over about 30,000 hectares when pest numbers have been high because of forest seeding.
Annual bird counts at more than 700 locations in the forest also show an increase in other birds such as robin and kakariki.
Waitutu Forest covers about 45,000 hectares of south eastern Fiordland and is one of the largest tracts of unmodified lowland forest left in New Zealand.
It has an important South Island kaka population, small numbers of endangered mohua/yellowhead and many other forest birds such as robin, rifleman, kakariki and ruru/morepork.