The Department of Conservation says its rangers will continue looking for as long as it takes to catch a stoat sighted in early November on Kapiti Island.
A dozen DoC workers have cut 20 kilometres of new tracks across the bird sanctuary and placed 180 traps which have to be baited every seven days, but with no result.
A specially trained dog has found evidence of the stoat - faeces and a half eaten kakariki - but has not managed to track the pest down.
DoC ranger Clint Purches says staff are in for the long haul and it could take months to catch the stoat and then a year after that making sure it was the only one.
Mr Purches says the Kapiti rangers' worst nightmare is a pregnant female because they can have up to 10 young.
He says the operation has cost about $25,000 so far.
