London's sparrows are in decline

The number of house sparrows in London has fallen so dramatically that experts fear the bird could disappear from the city forever.

Now the public is being asked to take part in a survey to find the few remaining house sparrows in London's parks and gardens so the birds can be monitored and cared for.

The survey, which begins today, will continue until 12 July and is being run by the London Biodiversity Partnership.

The group is hoping to discover what is causing the alarming fall in the numbers of the unassuming dull brown or grey bird. In 1925 there were 2,603 house sparrows recorded in Kensington Gardens but this spring just four were found. The decline has happened gradually. A count in 1948 recorded 885 house sparrows, while in 1975 there were 544 and in 1995 the number had dropped to just 46.

Keith Noble, London sparrows officer for the Royal Society for the Protection of Birds, said: "We are very puzzled. We want to know why they are disappearing. What we know at the moment is that they are not where they used to be. It's a mystery. While we are doing some research in various places we don't have the answer. Some people think it is a shortage of food but we can see other birds flourishing in Kensington Gardens. Unfortunately, all we can do is speculate."

He added: "Over the past 75 years the population has fallen from literally thousands to just four birds in Kensington Gardens today. We also know there are no sparrows in Hyde Park or St James's Park. It is very sad."

House sparrows were once a familiar sight in city centres around the country, nesting under roofs and raiding gardens for seeds and insects.

Mr Noble said what was happening in London was not unique: "We see the Royal Parks as an indicator of what is happening much more widely. It is patchy but across the whole of London there is a decline of serious proportions and in most parts of Britain it's the same."