Hunua Ranges 1080 drop programme wipes out rats and possums
Aerial 1080 poison drops in Auckland's Hunua Ranges have dramatically reduced pest numbers, an Auckland Council report says.
The poison drops, which cost over half a million dollars, have virtually wiped out both rat and possum populations in the Hunua Ranges regional parklands, according to the report.
The report's findings were published in an open agenda for a meeting of Auckland Council's Regional Strategy and Policy Committee on March 3.
In the areas targeted by 1080, possum densities are below one per cent.
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Rat densities are down from 91.6 per cent to 1.03 per cent, the figures say.
Crucially, no rats have been detected in the Kokako Management Area, where Auckland's only naturally occurring kokako population lives and breeds.
Thirteen kokako chicks have fledged in the 2015/2016 breeding season, compared to none during the previous year's season. Hochstetter's frogs, another threatened species that calls the park home, have also benefited from the pest control operation.
The report says further range-wide pest control using 1080 will likely be needed to maintain the 2015 operation's gains. However, due to the success of the aerial 1080 operation no further possum control is planned for the Hunua regional parklands until winter 2017.
It also notes the 1080 operation encountered peaceful protests, and there had been issues with members of the public ignoring warning signs and entering the park when it was closed for the poison drops.
In addition, a dog had been killed by secondary 1080 poisoning during the operation.
Hundreds of samples were taken from reservoirs supplying Auckland's drinking water before they were returned to service. No 1080 was found in the water.
Further drops in pest densities could mean other threatened species, like the North Island brown kiwi, are reintroduced to the Hunua area, the report said.