Pests set to survive cold but their predators suffer

Garden pests are expected to be among the big winners of winter as their predators are killed off by the freezing conditions.

Many birds are struggling to find enough food and keep warm during the coldest winter in 20 years and are dropping from the trees.

Contrary to the widespread belief that a cold winter kills off pests, many of the bugs that are the bane of the gardener's life are able to avoid the worst of the conditions by finding sheltered spots and remaining dormant until the weather becomes milder.

Slugs are among those that should emerge in the spring untouched by the frosts and snow, having safely buried themselves well away from the chill.

"Things that run about in the earth can go into hibernation and will be protected," said Stewart Henchie of the Natural History Museum in London. "Lots of these bugs have protection that can withstand much more than the temperatures that are being experienced this winter. These animals have evolved through all sorts of nasty extremes – both high and low temperatures. The slugs and snails and their eggs are all in the soil and are perfectly designed to withstand low temperatures."

Andrew Halstead of the Royal Horticultural Society also warned of a possible boom in pests later this year. "It's probably not the effect that most people expect," he said. "The biggest impact is probably not so much on the pests but on the birds that eat them. They can suffer in a cold winter much more than the pests.

It's only the coldest winter in 20 years because it's been so mild in recent years, he said. "If you look back over a longer time scale, there's nothing especially extreme about this winter. Native pests have adapted to much harder winters than this one."