From monitored rat tracking, the Department of Conservation (DoC) recorded a decline in rat numbers from 37 per cent to 0 per cent following the 1080 drop across more than 2000ha in the area last year.
DoC's rat monitoring uses 200 tunnels with ink pads to monitor tracks of anything that runs through them. A 37 per cent index meant 37 of the 100 tunnels showed rat tracks.
DoC said the reduction of rat numbers would increase the survival chances for the endangered North Island kōkako, of which just 94 adults were found in Mokaihaha in last year's survey.
DoC operations manager Jeff Milham said the success of previous pest control programmes enabled the endemic kōkako to thrive at Mokaihaha.
"There are only 11 original kōkako populations now left in New Zealand, and Mokaihaha is among the five most genetically diverse of these populations."
DoC community supervisor Barbara Curtis said options for effective pest control in larger areas were limited and no single method of control was suitable for all situations.
The use of traps and toxins together was a common pest control for conservation, she said.
She said helicopter sowing of 1080 was "very effective" for controlling pests, and satellite navigation technology produced targeted coverage to exclude important areas like Lake Rotohokahoka.
Ashton said population control was always a complex issue but SAFE urged the Government to prioritise research into more humane alternatives.
She said 1080 was banned in a number of areas, including Brazil, Belize, Cuba, Laos, Slovenia and Thailand and the majority of the world's 1080 was dropped in New Zealand.
"No animal deserves a slow and painful death. So let's look for other options."
Biodiversity ranger Maurice Wilke said research showed more than 5 per cent of rat tracking would result in a poor breeding season for the kōkako and other vulnerable birds, while 37 per cent would have resulted in a complete loss of kōkako nests this year.
He said no kōkako appeared to have died as a result of the drop.
As well as kōkako, other native birds such as the North Island robin, North Island kākā, tūī, bellbird, whiteheads and native bats were predicted to breed prolifically.
Rimu had also been noted to fruit heavily this year and, without pests competing for food, species such as kākā and kererū would stand a better chance of rearing young.
An SPCA spokesperson said while they stood by protecting native New Zealand species, there needed to be significantly more investment into research and development for humane alternatives to poisons.
The SPCA strongly advocated for the use of viable, humane alternatives such as humane traps and that the use of poisons be stopped as soon as possible.
Regional Economic Development Minister Shane Jones and Conservation Minister Eugenie Sage announced last week a $19.5 million investment from the Provincial Growth Fund (PGF) to develop innovative approaches to expand predator control in regional New Zealand.
Jones said the funding would be used by Crown-owned company Predator Free 2050.
"The new approach will also focus on maintaining predator-free environments using innovative techniques once initial eradication in the project areas has been achieved."
Conservation Minister Eugenie Sage welcomed the commitment from Predator Free 2050 to invest in research and development that would improve predator eradication tools and technologies.
"This project will help stimulate rapid innovation in the design of products such as more effective traps, lures, remote sensing, surveillance and data management technologies.
Curtis said once pest populations were reduced using aerial 1080, they could be held down by ground control methods. As populations of pests returned in the surrounding areas, another aerial operation might be required.
Pet owners are reminded to take care in the area and pay attention to the displayed warning signs.