Scientists are asking farmers to help investigate the mystery of Britain's disappearing starlings.

Once the chirpy chatter of the starling was one of the most recognisable countryside sounds. But across the UK their numbers have declined by 80% since 1979, and by nearly a third in the past 10 years.

The fate of the starling is part of a bigger picture affecting Europe. Over the past three decades, an estimated 40 million birds have vanished from the EU.

Experts from the Royal Society for the Protection of Birds (RSPB) have launched a new research programme to find out what is happening to the starling.

Working with farmers in Somerset and Gloucestershire, they will look to see if the birds have sufficient food and nesting sites.

Dr Richard Gregory, who heads the RSPB's bird monitoring section, said: "Our records show that we have lost more starlings across Europe than any other farmland bird. Forty million starlings lost represents over 150 for every hour since the 1980s. This loss should be a wake-up call."

In parts of Europe, loss of grassland through conversion to forestry land and the growing of crops have been blamed for reduced starling numbers. However, such changes have not affected Britain in the same way.

Martin Harper, the RSPB's conservation director, said: "We don't know the reasons for the starling's decline, but we hope that our research will yield the answers to ensure this bird has a secure future.."

Starling numbers have been tracked by the RSPB's annual Big Garden Birdwatch, the world's biggest wildlife survey.

Latest figures show starling declines of up to 80% in English counties between 1993 and 2012. In Scotland, numbers have fallen by 26.8% over the same period, and in Wales by 28.9%.