Are starlings going the way of the sparrows?

Twenty years ago, 100,000 of them flocked to Leicester Square in London every night, and now they've gone completely. Not hippies, not punks, not even Japanese tourists, but starlings.

The small birds that only a few years ago made gigantic cloud-like flocks over most of Britain's main cities as they came in to roost for the night have crashed in numbers by more than 50 per cent in just two decades, and almost everywhere, the great flocks have vanished.

Now their decline is to be investigated by scientists studying the parallel decline of the house sparrow, the subject of a long-running campaign by The Independent.

The disappearance of Sturnus vulgaris is at once less and more dramatic than the sparrow's. Less so because it is less complete: starlings can still be seen in our cities, while in many city centres the house sparrow has vanished completely. But it is more dramatic in the disappearance of a great natural spectacle.

Chris Feare, a former head of bird research at the Ministry of Agriculture who is Britain's leading starling expert, said: "The assembly of starlings at a big roost is one of the most spectacular sights in ornithology. You get cloud-like formations of birds. Each cloud seems so well co-ordinated, and the whole flock just shifts together."

Alison Hayes, a photographer working in Glasgow, has taken a remarkable series of pictures of starling flocks and the strange, tight shapes they assume in the sky, which change in an instant in the manner of a kaleidoscope. "The patterns that they make when they swarm are quite uncanny," she said.

Roosts in the past could reach a million birds, says Professor Feare, which makes these the biggest bird flocks Britain sees. He estimated the Leicester Square flock, which used to wheel, chattering, over queuing London cinema-goers, to be 100,000-strong. (The collective noun for starlings is "a murmuration".)

They started to enter the national consciousness. In 1949 the birds stopped Big Ben due to their weight on the hands of the clock, leading to questions in Parliament. Later, a whole episode of The Goon Show was devoted to the starling menace.

Similar flocks used to crowd the skies over most of our big cities. Now nearly all have disappeared, but bizarrely, the phenomenon has hardly been remarked upon by the public. "The Leicester Square flock went in the late 70s or early 80s," said Professor Feare. "I gave a talk to the London Natural History Society five or six years ago. They hadn't even noticed that the birds had gone."

The national censuses of bird species done by the British Trust for Ornithology show the starling crash has followed that of many farmland birds such as the skylark, the corn bunting and the yellowhammer.

For the starling is only 50 per cent a city bird. It spends much of its waking time on agricultural land seeking the insect food it needs. Professor Feare believesthe decline of insect populations over the past 30 years may be the key to the starling's decline.

He will be working on the starling part of the 18-month government research contract that is also looking at the house sparrow's decline.