The Department of Conservation says a recent 1080 drop over Northland's Russell Forest has been even more effective than anticipated.
In September Newshub Nation attended the aerial pre-feed operation, where baits not laced with poison were dropped so that rats and possums got used to feeding on them.
This meant a few weeks later, when the baits containing 1080 were dropped, they decimated the rat and possum populations. Nearly all the rats have been wiped out and 80 percent of the possums have been killed according to DOC monitoring.
The 1080 drop was part of the 20-year Forest Health Plan developed by DOC and nine local hapū, after a series of viral videos from Forest and Bird in 2015 revealed the extent of damage that pests had wrecked on Russell Forest.
"The birds have virtually disappeared - if you go there now you won't hear any kind of dawn chorus, so to return all of that we need to work through the birds' food chain," Rōpū spokesperson Kara George told Newshub in February.
The 1080 operation came just before the spring breeding season, giving native birds in the forest a higher chance of raising the chicks successfully.
"This spring, native birds have finally been able to to nest in peace, and instead of rats and possums feasting on the flowers and leaves of native trees; native birds, insects and lizards have benefited instead," says Forest & Bird's Northland Conservation Advocate Dean Baigent-Mercer.
"Reducing the pests to such a low level is just the beginning of the work. DOC are committed to working with hapū and communities to keep these pest numbers low and bring back the kūkupa, Kiwi and other native species to the forests," says Ms Reed Thomas.
"We will continue to support the work of the Russell Rōpū to implement the 20-year forest health plan, with the long-term goal of forest restoration. The use of aerial 1080 to restore the forest is the first step in the plan."
DOC measures the number of rats in an area using tracking tunnels with ink pads and baits. Prior to the 1080 drop, 76 percent of the 160 tunnels in Russell Forest had rat footprints. Now, just one tunnel has rat footprints.
Possum numbers are measured through wax tags, with 79 percent of the tags having been chewed on before the drop, compared to 16 percent after.
Stoats, feral cats and other predators are more difficult to track. However, based on previous operations in other areas it's estimated the majority of stoats would have been killed through secondary poisoning from eating poisoned rats.
Forest and Birds hopes the success of this operation will help other iwi and hapū in the area see the benefits of 1080 for pest control.
"Tragically, most of Whangaroa Forest continues to collapse after the postponement of an aerial 1080 operation this year," says Mr Baigent-Mercer.
"All Northland native forests without comprehensive pest control have been collapsing for decades."