British Bird Decline
(This column was first published in the August 4, 2003 issue of The Buffalo News.)
Be careful: Sometimes your wishes may come true.
That strange warning seems to be playing itself out today in Great Britain where between 1972 and 1996 the national house sparrow population fell by 64%, a loss of 9.6 million birds. Over a similar period British starlings lost 57% of their population, 11.5 million birds.
An extreme example is London's Kensington Gardens where the number of sparrows dropped from 2600 in 1925 to 544 in 1975 and to eight three years ago.
Here in North America house sparrows and starlings, aliens to our continent, have few defenders. They're messy birds and they often muscle aside our more retiring songbirds at nest-boxes and feeders. And they have become our most common species: their numbers make up over 30% of the birds on area Christmas Counts. In fact, house sparrows aren't even related to our native song and chipping sparrows; they belong to the quite distant family of weaver finches.
A friend calls them rats with wings.
But the British experience leaves me with a niggling concern. I wonder if some of the same kinds of things might have been said of the passenger pigeons that darkened our skies during their 19th century migrations. There were so many of them that they could quickly denude a forest of its fruit and nuts.
Today we think of the passenger pigeon as that splendid lost game bird, but what would we have thought then if we had hundreds of their nests in each of our yard trees as was sometimes the case?
Whatever our feelings about these ubiquitous birds might be, it is clear that the British are concerned about the loss of their "cockney sparrow".
The Lord Mayor of London, Ken Livingstone, has spoken out about them: "The sparrow is part of London's identity and their friendliness has helped make wildlife accessible to all Londoners. Their decline should worry us all - the sparrow's world is our world. If something is wrong with the sparrow, it is vital that we find out what's behind it."
Comments of others included, "Poor old Sparra! Why couldn't it have been the pigeons instead?" "Maybe it's revenge for Poor Cock Robin," and simply, "Gawd bless 'ya!"
This May British citizens were asked to count sparrows in their gardens. An extraordinary quarter-million people responded, providing data that clearly indicates that urban birds have fared worst.
There are still many sparrows in the United Kingdom, those counts turning up an average of over seven per garden. The data makes clear, however, that the urban birds are suffering major declines. While rural Lincoln gardens average over nine sparrows, Londoners find less than five.
No one seems able to pin down the reasons for the declines. Among the candidates: changes in house design leaving fewer roof cavities; less loose grain; growing cat numbers; an increasing population of sparrowhawks (a British relative of our kestrel); in the country changing farming practices and a lack of hedgerows; and in the city air pollution. Specifically singled out for study because their increased use correlates with the bird decline have been two ingredients in lead-free gasoline (petrol in England): MTBE and benzene.
Whether or not we like these species we, like the British, should be concerned because they may be playing a warning role like the canary carried into the mine. As with our own serious decline in crow populations - identified with the spread of West Nile Virus - they may be indicators of concern for other less populous birds.
And they also raise concerns about our own health.-- Gerry Rising