The decline of the house sparrow is not restricted to India. London bird-watchers too have been noting its vanishing with concern. Buckingham Palace, reputed to be the richest wildlife area in central London, has seen its sparrow population dwindle to zero.
The British Trust for Ornithology's (bto) Common Bird Census Programme recorded a 58 per cent decline from 1973 to 1988 across the rural areas of the uk. A bto nest census reported a 53 per cent decline in both rural and urban areas. Sparrow expert David Summers-Smith, who has been working on sparrows for the last 50 years, records a 95 per cent decline in the urban centres of London, Glasgow, Edinburgh and Dublin. He hypotheses that the decline of the house sparrow in London coincides with the increase in traffic and the introduction of unleaded petrol. The new toxic compound (benzene and methyl tertiary butyl ether), that replaced lead in petrol, may be killing insects on which young sparrows depend almost solely for nourishment.
The fall of the British sparrow could well have started as early as the turn of the 20th century, when automobiles began replacing the horse-drawn carriage. The trails of feed that leaked from coaches used to provide sparrows with easy pickings. But the disappearance of horses from urban roads meant that sparrows were deprived of a valuable food source which used to be available not too far from home.
The diminutive sparrow has a small roaming range. Plus, it needs to find insects to nourish it's young. But garden herbicides and pesticides have reduced insect population, depriving the sparrow of sustenance. The British are so concerned about their missing sparrows that The Independent has even instituted a sizeable reward of 5,000 to anyone offering convincing scientific evidence on the reasons for the little bird's woes.
A study conducted in the Netherlands by Guus Van der Poel found that the house sparrow was almost extinct in those urban residential areas, where most houses had been built before 1953. But the bird was found to be thriving in the more recently built areas. His reasoning is that older cities lack sufficient amount of insects. As a result of the extensive building activity of the past 30-40 years, many older towns and city centres have drifted too far away from their former rural surroundings. He concludes that the decline of sparrows in their traditional breeding sites in the urban areas of larger towns is due to the paucity of appropriate food during breeding seasons and suitable nesting venues.
It is the same sad story for the sparrow all over the globe. Changing lifestyles and architectural evolution have wreaked havoc on the bird's habitat and food sources. Modern buildings devoid of eaves and crannies, disappearing home gardens and crop fields cleaned of insects by the use of chemical pesticides, all play a part in denying sparrows nesting sites and food, especially for the young.
To protect our avifauna and life-supporting systems from so-called 'development,' sacon has launched the Common Bird Conservation Pro gramme. This is in addition to the Endangered Species Conservation Programme, which is investigating factors affecting the populations of endangered birds. Under the new programme, a nationwide network of bird lovers will participate to address issues related to common birds. Relevant conservation information will be collected. In the first phase, the project will gather data on common birds, especially house sparrows, throughout the country.
The scheme also aims to collect facts on habitat changes in a particular area. After preliminary analysis of the data, three to four areas where sparrow populations have fallen the most, will be selected for intensive study to identify the affecting factors. The project will include the various common bird species populating India's cities, suburbs and villages.
I rest my case with a chilling thought from Guus Van der Poel of the Netherlands: "I am personally worried because the house sparrow shares it's environment with my own little grandchildren and the cause of the present decline of this species is unclear and perhaps, might even indicate noxious conditions for these birds which could also have long-term implications for my grandchildren -- who knows!"
V S Vijayan is director, Salim Ali Centre for Ornithology & Natural History, Coimbatore