'Work needed' on 1080 drops

A Government pest ecologist says more work is needed to find out how rare birds respond to new methods of applying the poison 1080.

Department of Conservation ecologist Dr Clare Veltman said there had been enough studies in the past 20 years to be very confident that kokako, kiwi and kaka were at low risk from 1080.

However, it would be prudent to study the effects of the latest method - dropping non-toxic baits first to encourage possums and rats to eat baits, she said.

Dr Veltman presented her findings at the tenth annual International Ecology Congress in Brisbane this month, after a review of 40 published and unpublished studies, most of them carried out by DoC.

She said monitoring between 1986 and 2006 found no birds died during nine studies of kiwi, eight studies of kokako and four studies of kaka in 1080 drop zones.

But of 19 birds known to be affected by poisoning, just eight had been surveyed when Dr Veltman completed her review.

The others were blue ducks, weka, moreporks, robins and kereru - of which hardly any were found to have died, she said.

Her review did not include a recent study of kea in Kahurangi National Park in June, when DoC monitored 13 kea and found all were still alive a month after 1080 aerial drops.

Dr Veltman said more work was needed to predict effects on other birds. Research had tended to target the most threatened species first, she said. "By 2000 we had precisely one survey of kereru."

Native birds such as fantails and pukeko did not need tracking because they bred easily.

One of New Zealand's most endangered birds, the kakapo, had never been exposed to 1080, she said.

Dr Veltman said DoC was adding to its collection of studies on a drop-by-drop basis.

The Environmental Risk Management Authority reviewed the use of 1080 and last year concluded that the benefits outweighed the risks.

However, a vocal group of opponents believe the pesticide is poorly understood and too often kills the wildlife it is meant to protect.

Dr Veltman said the advent of precise helicopter GPS systems and other baiting methods over the past 20 years meant predators could be killed using ever-decreasing amounts of poison.

The goal was to create safe havens outside of island and fenced sanctuaries, where predators were scarce enough to allow birds to live and breed, she said.

More work was needed to show how bird populations outside sanctuaries responded to lower pest numbers: "We know from (fenced and island) sanctuaries that if you can get the pest population out, the birds blossom."

Dr Veltman said GPS had helped with pest control because helicopters could lay baits in precise rows, so there were no gaps for rats and possums to repopulate from inside the baited area.