Plague unlikely as rats come in from the cold

More Norway (brown) rats are likely to be seen after recent rain.

Northlanders noticing more rats around - fear not - it's just an increase of rodents seeking shelter in homes and garages after last month's rain and not an increase in the population, the Department of Conservation (DoC) says.

DoC senior services ranger for Whangarei Nigel Miller said if people had seen an increase in rats it was likely wet conditions had moved Norway (brown) rats from tunnels into warmer, drier houses and garages.

"I'd say it's a weather-driven event. The good thing about wet and cold conditions is that rats in the bush will probably die."

There are a lot of rats around Northland at this time of year anyway, Mr Miller says.

"Northland has high numbers of rats anyway. It's pretty mild here [in terms of temperature] so rats do better here [than elsewhere in New Zealand]. Autumn is when rats are at their complete peak, so it won't be long for before they start breeding again," he said.

Phil Pumstall, owner of Whangarei-based pest management company Enviropro Northland, said while the company was doing "rat jobs" every day, he doesn't think rat numbers are up on last year.

There was, however, a noticeable surge in rats entering properties after all the rain.

"They don't want to be wet and cold in the rain so they get in the roof where it's nice and warm."

Whangarei District Council offers free rat bait to residents, and spokeswoman Ann Midson said there had not been a difference in the number of people given bait on the previous year.

Mr Miller said the best way to kill unwanted rats was with traps and poison.

"Kill them away from your house. [Set] two or three traps around your house, up to 100m away. Get on to them before they get into your house.

"The bigger scale of rat control, the better."