THE savage wintery weather is pushing the Forest of Dean wildlife to the brink of a crisis and the RSPB is urging people to help struggling wildlife through what, potentially, could be the greatest single wildlife killer of the new millenium.

Finding food and ensuring they eat enough to build and maintain adequate fat supplies to store on the body and 'burn' for energy is the greatest test for wild birds in winter. The food and water we provide can be the difference between life and death in many cases.

When temperatures fall below freezing our birds struggle to find the food they need to survive the winter in healthy condition - vital for breeding in the spring.

Natural food is covered in snow and ice and impossible to get to. The ground becomes too hard for birds like blackbirds and song thrushes to probe and natural food like berries, acorns and seeds are buried.

People can help improve birds' chances of survival through these cold periods by providing food like meal worms, fatballs, crushed peanuts, dried fruit and seeds and grain. They could also put out leftovers like grated cheese, porridge oats, soft fruit, unsalted bacon, cooked rice and pasta and the insides of cooked potatoes.

Water is also vital for both drinking and bathing and bird baths can be kept from freezing over by using small floating items like twigs or ping pong balls.

Many people have telephoned our local RSPB office describing a large thrush-like mystery bird in their gardens. A bird with a grey head and tail, brown back, ochre breast and white belly. This is the fieldfare, a winter visiting thrush that usually spends its time in our fields. However, the freeze has pushed hungry flocks into the Forest of Dean area, with them being seen at Nagshead Reserve, which is quite unusual. They particularly enjoy apples and berries, though they do have a habit of earnestly defending their food and will chase away all other birds.

People may also notice a change in the behaviour of birds, given the extreme conditions. You may witness a flurry of activity first thing in the morning - as birds replenish energy lost overnight - and last thing in the afternoon - to prepare for the long night ahead.

In Cinderford it has been reported that the usually solitary and territorial robin has been seen feeding together in groups, begrudgingly tolerating each other just trying to survive during the most extreme of conditions - often feeding with thrushes on the disturbed soil where wild boar have been feeding.

Another unusual behaviour reported was a flock of around 15 wrens all going to roost together in a hole in a tree. Again, the wren is usually territorial and quite intolerant of its own kind, but in the extreme cold it resorts to this behaviour of communal roosting just to survive the sub-zero temperatures through the night.

This year's Big Garden Birdwatch on January 30-31 will be particularly interesting as it may answer questions like: Will the cold weather have affected numbers? How will the smaller birds have coped? Will the fieldfares still be around?

Tips on feeding birds in the big chill

•Put out feed regularly, especially in severe weather. Set up a bird table and use high calorie seed mixes. Top up with kitchen scraps such as animal fats, grated cheese and porridge oats.

•Put out hanging feeders for black sunflower seeds, sunflower hearts, sunflower-rich mixes or unsalted peanuts.

•Make sure there's a supply of fresh water every day. If it is very cold use tepid water but don't use antifreeze products

•Put out fruit, such as apples and pears for blackbirds, song thrushes and other members of the thrush family.

•Food bars or fat hung up or rubbed into the bark of trees is a great help for treecreepers, goldcrests and many other species.

•Put up nest boxes to provide roost sites for the smaller birds – they'll be used later in the year for breeding.

•Leftover meals can also provide a welcome boost for wildlife – cake crumbs, pastry and cheese are all readily eaten by wild birds.