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Kaka Catastrophe

The sight and sound of the kaka may soon be a thing of the past in New Zealand mainland forests, according to scientists who have seen the native parrot's population decline over the last decade.

Landcare Research biologist Peter Wilson says three of the five nesting females found in the Nelson Lakes study area this season have been killed by predators.

"The kaka is in dire straits. The population is made up mainly of males without mates, so there is little prospect of them reproducing."

No breeding was recorded in 1993/94; in 1992/93, three nests produced ten chicks, but only two chicks survived predator attacks. This season, predators discovered the nests early and only two eggs hatched in one nest. The mother was killed soon after, probably by a stoat, and her young were rescued by Landcare staff.

Wilson says the loss of females is worse than the high mortality of chicks, indicating the kaka is heading towards extinction on the mainland. It is now considered threatened, with small numbers surviving in forest remnants in the North and South Islands, and on predator-free offshore islands. Competition from introduced animals and habitat loss and modification have helped account for the bird's decline this century, but predation has been the final blow.

"Wasps competing for honeydew and possums feeding on plants have affected resources, but it looks like stoats are the main villains in killing adult females."

He says intensive trapping and the development of better methods of controlling stoats is needed to create mainland kaka breeding enclaves. Researchers will continue to monitor nests and investigate how stoats locate the nests. Wilson believes mainland sanctuaries are feasible but will require more resources than presently available.