The Department of Conservation has completed its 'Battle for Our Birds' aerial 1080 poison drops over about 257,000ha of the Kahurangi National Park the largest in one area it has ever carried out.
DOC said die predator "triple-hit" would protect whio (blue duck), great spotted kiwi, kea, kaka, rock wren (tuke), powelliphanta snails and long-tailed bats (pekapeka). The aerial pest control in western, northern and eastern park areas was divided into five operational blocks, with the last two of the five operations completed in western areas of the park and the Cobb Valley and surrounding areas over the past three days.
DOC Westport conservation services manager Bob Dickson said "nesting native birds have a much better chance at raising chicks to grow their populations".
Monitoring is taking place to measure the effects of the pest control on rat levels.
Warning signs are in place at entrances to the Kahurangi pest control areas and 'in huts to advise the public of the risks of the pesticide and poisoned carcases.
Mr Dickson said tracks were either excluded from the 1080 application or temporarily closed and cleared of baits before they reopened.
The Kahurangi pest control is among 25 'Battle for Our Birds' operations nationally using aerial 1080 poison over about 700,000ha of conservation land.
Aerial 1080 predator control has been completed over more than 60% of the total area so far.