Looks as if they are going the way of the dodo
When did you last spot a house sparrow (Passer domesticus) in your house? Chances are, quite a while ago. These once-common birds are becoming a rarity, in India and other parts of the world. The Royal Society for Protection of Birds (rspb), uk, recently added the house sparrow to its Red List (for rapidly declining bird populations, which pose global conservation concern).
Many of our so-called 'common' birds are at grave risk. This might sound a trifle melodramatic, but I'm definitely not exaggerating. At the beginning of the 19th century, few would have thought that the passenger pigeon would become extinct one day. But it did happen. The passenger pigeon population was estimated at between 5-10 billion in the first half of the 19th century. In the next few decades, all the birds were gone. Their demise was not due to disease or habitat destruction. The hapless avian species died out solely because it was mercilessly hunted down for meat.
The white-backed vulture is another example. In 1995, during a workshop sponsored by the Salim Ali Centre for Ornithology & Natural History (sacon), BirdLife International and the Wild Bird Society of Japan, Indian delegates were opposed to classifying the white-backed vulture under the "threatened" category. By 1998, the bird had become rare to spot. The 4000-odd vultures seen thronging Delhi's garbage dumping areas in the early 1980s had disappeared totally. Several theories were floated around after it was too late; preventive measures by airport authorities to reduce bird hits on planes, environmental contamination, poisoned carcasses and viral disease, to name a few.
The house sparrow is another fast disappearing 'common' bird. This avian species can still be spotted at over two-thirds of the world's land surface. But reports are pouring in from all over India and around the world of rapid decline in the populations of these once abundant birds.
The ancient Romans introduced the house sparrow to Europe from North Africa and Eurasia. Human exploration and migration then took the bird to many other parts of the globe, including North and South America, South Africa, Australia and New Zealand.
Being a social bird, the sparrow thrived around human beings and where grain was abundant. Despite being derided as 'avian rat' in the late 19th century (for damaging cereal and other crops), the sparrow steadily 'colonised' a number of countries. The demise of vast numbers of this spunky bird is all the more shocking since it is a survivor; sparrows have been found breeding high up in the Himalaya and down below in Yorkshire coal mines.
Avid bird-watchers from all over India have contacted sacon about the decline in the sparrow population of their locality or city. Subramanya, a sacon member in the National Wetland Conservation Programme and currently working with the University of Agricultural Sciences, Bangalore, confirms the decline of sparrows in Bangalore. He attributes it to the lack of nesting sites in modern concrete buildings, disappearing kitchen gardens and the non-availability of a particular larvae (Helicoverpa armigera), associated with the field bean.
The field bean theory is particularly interesting. Formerly, urban households in India used to buy field beans as pods in vegetable markets. When the pod was broken, larvae came out, to be promptly devoured by sparrows. But now that fresh seeds are available in packets, these larvae have disappeared, depriving the sparrow.
At the M S University campus in Baroda, house sparrows have been studied extensively since 1960 using nest boxes. Bony Pilo of the Zoology department reports that these boxes have been lying vacant for the last few years, marking a definite fall in the campus sparrow population. Dr. Shyam Sunder Rao, head of the All India Coordinated Project on Agricultural Ornithology, reports declining sparrow populations at most of the places where studies have been conducted.
Despite the gloomy news from all around, there are still some rays of solace. Sparrows have been thronging the new sacon campus at Anaikatty, Coimbatore. Today there are about 30 of these birds on the campus. This contrary phenomenon may be due to the campus' environment-friendly buildings designed by renowned architect, Lawrie Baker. The ventilators in these buildings offer cosy nesting sites for sparrows.
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
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