THE RSPB is appealing to people in Worcestershire and Herefordshire to take part in the world's biggest bird survey.

The society's Big Garden Birdwatch runs on Saturday, January 29, and Sunday, January 30, and more than 500,000 people are expected to take part.

The aim is to find out which birds are the most common visitors to gardens in winter but also to keep an eye on how others are faring.

Participants should spend one hour counting the birds in their garden or local park, and record the highest number of each bird species seen at any one time.

Morning is the best time to look, when birds are active after a cold winter night.

Last year, the organisation received a total of 6,500 entry forms from residents in Worcestershire and Herefordshire - with the blackbird, chaffinch, woodpigeon and robin populations all showing a slight increase on 2002's figures.

However, every other bird in the top 10 had decreased, with the biggest drops in the starling and blue tit population.

"There's a serious side to Big Garden Birdwatch - the details people provide help us to look at how birds are faring in different geographical areas," said Richard Bashford, RSPB Big Garden Birdwatch co-ordinator.

"This is important since some species, declining across the UK, may actually be stable or increasing in certain parts.

"The house sparrow is doing much better in Wales than in England, for example - so, the more people who take part the better the information gathered will be."

Since 1979 - the first Big Garden Birdwatch survey - participation has risen from 30,000 to 419,000, a figure the charity hopes to beat again in 2005.

The starling, beaten to the top spot in 2004 by the house sparrow, a first in the history of the survey, has seen its numbers plummet from 15 per garden to an average of 4.3, a decline of 71 per cent.

The house sparrow, with an average of 4.8 per garden, has declined by 52 per cent since 1979, when an average of 10 birds were seen.