The charity said many wildfowl no longer needed to migrate as far as the UK from places like Greenland and Siberia because of warmer winters.

Numbers of seven regular visitors, including the shelduck, mallard and turnstone, are declining, it warned.

Some species' population had increased markedly since the late 1970s, mainly due to conservation, a report adds.

The State of the UK's Birds 2006 report, says in particular the number of wading birds including the black-tailed godwit and the avocet, had increased markedly, mainly due to action by conservationists.

But as winters become milder both in the UK and elsewhere, it appeared that some birds were not forced to fly as far as the UK to find suitable conditions, the RSPB said.

Sea levels

Bird experts said the precise reasons for the decline of the seven species varied, but a common theme appeared to be climate change.

Dr Mark Avery, the RSPB's conservation director, said: "The UK has had both the perfect climate and perfect habitats for these birds, but the evidence is growing that climate change impacts are starting to bite.

"Sea level rise and warmer winters are reducing their numbers, undermining our importance for birds."

Conservationists say that every winter the UK is home to about five million ducks, geese, swans and wading birds.

They come from the icy lands of northern Europe, Greenland, Siberian and Arctic Canada and are attracted by the relatively milder winters and availability of food.

The report said climate change's affect on migration patterns had already been "particularly noted" in Northern Ireland with declines of pochard and Bewick's swan.

It is feared the areas used for winter nesting and feeding instead do not have the same food availability and may affect bird populations in the long term.

This is an article from th BBC Web Site:

 http://news.bbc.co.uk/1/hi/uk/6950711.stm

Sorry, but I don´t have time to write an article myself.

Yours as ever

Harold Hamlet