House sparrows are rapidly vanishing from many of Britain's big cities, a survey by The Independent indicates.
The bird thought of as the ultimate urban survivor, once present everywhere and as much as part of city life as traffic jams, is disappearing swiftly in big urban centres across the land. Its decline, which seems to have begun in the late 1970s or early 1980s, appears to have speeded up in the mid-90s, with some areas losing theirremaining birds in five or six years.
The cause of the decline is a mystery: reasons suggested include the disappearance of insect food because of pesticides, disappearance of nesting places as inner-city areas are tidied up, pollution, and - a favourite of many non-scientists - attacks by magpies and other predators with booming urban populations such as sparrowhawks and carrion crows.
The house sparrow has already vanished from central London, as The Independent reported three weeks ago, provoking considerable correspondence from readers.
Now they are also disappearing from such cities as Glasgow, Edinburgh, Liverpool, Newcastle, Leeds, Bradford, Southampton, Sheffield and Nottingham and are in decline in other centres such as Manchester and Bristol. Only in Cardiff do they appear still to be flourishing.
Even though Britain's birds are more intensively surveyed than those of any other country, the phenomenon has been little picked up or publicised inindividual cities so far because sparrows have been so common and inconsequential that birdwatchers have not bothered with them.
"You would miss them by their obviousness," said Brian Hallworth, a birdwatcher in Stockport, Greater Manchester. But he now looks out for sparrows, as a poll by The Independent of bird enthusiasts up and down Britain, in particular of the network of county bird recorders, has shown that the population crash seen in London is being paralleled in many other urban centres.
The fall in numbers across the country as a whole is being registered in big surveys. Two months ago the Royal Society for the Protection of Birds (RSPB) and the British Trust for Ornithology (BTO) jointly published the first in a series of annual reports on populations.
The State of the UK's Birds 1999 showed house sparrow numbers had fallen 58 per cent between 1975, when they were first monitored, and 1998. A 7 per cent decline for Britain as a whole was recorded in the years 1994-98 by the BTO's breeding birds survey.
But when cities and especially city centres are considered individually, some declines appear astonishing. In Glasgow, house sparrows have gone from the centre, said Ian Gibson, local bird recorder since 1975 and Glasgow City Council's conservation officer. "They've been diminishing for the last 10 years but the decline seems to have accelerated recently," he said. "Flocks used to be common in the city centre, and in particular round George Square but now in the city centre they seem to be extinct."
A more scientific survey of Glasgow's birds, by the world expert on the house sparrow, Denis Summers-Smith, found a density in the suburbs of 4.9 birds per hectare in 1959. When he repeated it in 1997, Dr Summers-Smith found a density of below 0.1 birds per hectare in an area four times as big.
A similar picture has been observed 50 miles away by the Edinburgh birdwatchers Harry Dott and Alan Brown, who observed house sparrows in Princes Street gardens from 1982-84 and again from 1997-99. In the first period the birds averaged between 200 and 300 in number; in the second period, between 20 and 30.
The declines are paralleled in such places as Liverpool, which had a large house sparrow population. Now, according to Eric Hardy, a naturalist who has written a local newspaper column for many years, they are present in only a fraction of their former numbers.