Call to step up rats battle.

Farmers across the North-East need to mount a concerted late-winter offensive to counter the hidden build-up of rats this season and prevent it exploding into serious problems from the coming spring, advises local rodent control specialist Charlie Ives

According to Mr Ives, of Sorex, farm rat populations have thrived in 2006 ( the warmest year since records began ( and the mild winter has allowed breeding to continue virtually uninterrupted, supported by abundant food sources.

And because the conditions have enabled so many rats to remain outside, their build-up has escaped largely unnoticed in many cases.

Mr Ives said: "What is more, with the Met Office predicting 2007 to be even warmer, rat populations are set to mushroom as soon as spring breeding takes off if they are not very firmly controlled in the remaining weeks of winter."

Mr Ives stressed that the final weeks of winter provide the best opportunity to get on top of the growing rat threat with good, behaviour-led control.

He pointed out that even in mild winters alternative food sources are becoming increasingly scarce by February or March, so rats will consume rodenticide baits more rapidly and readily.

"Of course, these baits need to be both sufficiently attractive and well-placed along established foraging routes to compete with remaining food sources and overcome rats' natural neophobia," he added.

However, Mr Ives said it was important that farmers act now or in the near future.

"As soon as spring arrives and they migrate back to the fields rats have a greater variety of foods to choose from. Their burrows and foraging routes are more difficult to pinpoint. They are more wary of "unnatural" bait containers essential to protect other wildlife. And bait points are less easy to keep topped-up.

"The official 2006 National Rodent Control Survey revealed a 22% increase in summer rat populations, and 85% of farmers in our own autumn study reported rodent control becoming increasingly challenging" added Mr Ives.