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Published: 2007-12-10 00:00:00

Environment Waikato’s first attempt at blitzing ship rats, a major tui predator, at its Whatawhata Hamilton Halo site has been a roaring success.

Monitoring carried out recently showed the council-funded project had achieved a zero per cent rat tracking rate following pest control operations in October and November.

Environment Waikato biosecurity officer Ben Paris said he was “absolutely stoked” with the results.

“This is great news for us because it’s the first time we’ve designed a pest control operation specifically targeting rats and as a prototype operation we were keen to test our theories,” he said.

“We’ll be carrying out more monitoring in the New Year to find out how quickly the population rebounds, but in the mean time tui chicks at our Halo site should be much safer in their nests.”

Landcare Research staff did the rat monitoring using small plastic tunnels fitted with ink pads and cardboard mats to record their footprints.

Rats had run through 60 per cent of tunnels in the pest control area beforehand, but not a single footprint was found after the operation.

Pest control was timed to coincide with the tui breeding season, which begins in November.

Rats do huge damage to native bird populations because they can climb trees and eat birds and chicks in their nests. Possums do the same, but possum numbers at the Halo site are already low and their numbers are also being controlled and monitored.

Landcare Research scientist John Innes said removing these two major predators from the site meant tui nesting success would increase from about 25 per cent to about 75 per cent.

“More tui will visit gardens between Whatawhata and Hamilton next winter as a result, and numbers will grow steadily over the next five years,” he said.

“The Whatawhata Halo site at Old Mountain Bush Rd is the nearest substantial piece of native bush to Hamilton. We know for certain that some of the tui there come to Hamilton – that’s part of the reason that site was selected.”

The Hamilton Halo project aims to bring tui and other native birds back to Hamilton by removing pests from breeding sites within 20km of the city.