The song of the bellbird is growing louder at Palmerston North's Arapuke Forest Park as efforts to control rat and possum populations take effect.
Both pests are destructive to the forest ecosystem, and both have been targeted in city council poisoning programmes.
Forester Mark Johnston said pest control was an important part of the council's programme to extend the network of mountainbike and walking trails in the Kahuterawa Outdoor Recreation Area, about 17 kilometres east of the city.
Monitoring indicated an 80 per cent drop in rat numbers, and a 90 per cent drop in the possum population over four years.
"Rats are as destructive as possums," Johnston said.
"They eat birds, their eggs and chicks, lizards, invertebrates and a wide range of native fruits and other plant material.
"Ship rats are good climbers, so can get access to bird nests high in trees."
The pest control programme was also giving extra protection to the native giant carnivorous snail Powelliphanta, which lives in the area, and there was a slow but steady increase in the amount of bird song being heard.
The area was proving to be a safe haven for native birds, said Peter Handford, manager of the monitoring organisation GroundTruth Ltd.
"There are signs of an increase in numbers of korimako, the bellbird, and a pair of one of our most spectacular birds, karearea, the New Zealand falcon, are using the area."
The poisoning programme began in 2010 around the Back Track and Sledge Track areas, on both public and private land, covering the 250 hectares of the Arapuke Forest Park area.
The cost of the programme is $15,000 or $60 per hectare.
Daniel Ritchie Contracting carries out the poisoning programme, and GroundTruth Ltd provides independent monitoring.
The controls used are feratox and brodifacoum bait, and flavoured paraffin wax blocks are used for monitoring purposes.
The blocks are impregnated with pink dye and aniseed that possums and rats chew, leaving bite marks.
Monitoring records the number and type of bite marks.
- Manawatu Standard
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