New Delhi: House sparrows are an indicator of the environmental health of an area, and their disappearance could be linked to a rise in infectious diseases and ecological change, say experts.
These common birds have been edged out of Delhi homes by changes in architecture and agriculture as well as urban predators like crows and cats, some top ecologists said at the India International Centre here Tuesday at a public lecture to discuss the mystery of the missing sparrows.
Starting the discussion after a small clip on the sparrow`s declining habitat by filmmaker Nutan Manmohan was shown, bird expert Surya Prakash said the birds had not vanished, but had been pushed out of their regular haunts.
"The sparrows are still there, but changes in our lifestyle, housing architecture, agricultural patterns and increasing urban predators such as crows and cats have forced them out of many areas where they were commonly seen earlier," he said.
Prakash, a professor at Jawaharlal Nehru University`s school of life sciences, said: "The lack of scientific data has also prevented experts from finding their actual status."
However, he agreed that the decline in numbers was a concern as it was a marker of deeper ecological changes in the city.
Fellow speaker Neeraj Khera agreed, claiming the declining numbers of sparrows could actually be used as a pointer to more direct problems such as an increase in infectious diseases.
"In the areas where the sparrows have declined, rock pigeons have increased drastically. And pigeon`s excreta is a confirmed carrier of disease causing bacteria," said Khera, a technical expert and ecological researcher.
"Although not linked directly, the decline in bird population and tree health can be used as an indicator of the environmental health of a region," she added.
Ecologist Koustubh Sharma said in Britain, the declining yard birds, which include house sparrows, was one of the 15 critical indicators of the quality of life in any area.
"Despite their importance, birds like the house sparrow are often neglected by even environmentalists due to their apparent commonness," he claimed.
Citing the absence of large-scale community-based data regarding house sparrows and other common birds in the country, Sharma claimed that a new citizen-scientist project website, www.citizensparrow.in, had been launched in April which focuses on the issue.
"Through this website, we aim at utilising the vast reach of the internet in capturing data about sparrows and their numbers from across the country," he said.
Sharma added that besides generating useful data, the website also served as a tool to generate awareness among the public about sparrows and said there could be progress only if there were focused studies on these changes in sparrow population and the reasons behind them.