The Hindu : Opinion / News Analysis : Keeping a watch on winged visitors

Online edition of India's National Newspaper
Thursday, Nov 10, 2005

Opinion

Opinion - News Analysis

Keeping a watch on winged visitors

N. Gopal Raj

A key part of the Union Government's strategy to protect the country from bird flu outbreaks is to monitor wild birds for signs that they might be diseased or infected.

AMIDST FEARS that migratory birds may be capable of carrying and spreading the lethal H5N1 bird flu virus, there are concerns that wild birds coming from Siberia, parts of Central Asia such as Kazakhstan, and northern China where viral outbreaks have occurred might bring the virus to India. A key part of the Union Government's strategy to protect the country from bird flu outbreaks is to monitor wild birds for signs that they might be diseased or infected as well as to keep surveillance over poultry around areas where migratory birds gather. It is a strategy that depends on knowledge of where the birds are coming from and the places to which they might travel in India.

That knowledge has been gained by "banding" migratory birds. Wild birds are caught by experienced trappers without harming them, a light aluminium band is fixed around their legs, and the birds are then released again. If a banded bird is captured again or killed, the metal ring tells people to inform the organisation that tagged it. The band also carries a serial number that allows the bird to be identified.

The venerable 120-year-old Bombay Natural History Society (BNHS) began banding migratory birds in 1959 following a viral outbreak. "The outbreak of a form of encephalitis in the Kayasanur Forest area in Mysore, the virus of which was reported in 1957 to be related to a group of viruses occurring in Omsk in the [former] U.S.S.R., suggested the possibility of its having been carried by migrating birds," wrote Salim Ali, the famed Indian ornithologist and former president of the BNHS, in a paper he later published in the society's journal. He put forward a scheme to the World Health Organisation (WHO) for establishing a bird-banding centre in the Rann of Kutch to determine whether ticks carrying the virus were hitching a ride on migratory birds.

The WHO-funded banding programme continued intermittently up to 1973. Then it was resumed only in 1980 when the U.S. Fish and Wildlife Service supported projects to study Indian birds and their movement. After these projects ended in 1992, bird banding activities in India almost came to a halt.

The BNHS has ringed over 400,000 birds in various parts of India, according to a report published by the society. The intensive bird migration studies carried out between 1980 and 1992 had, according to the report, generated enormous amount of data on migratory patterns, seasonal movement, migration routes followed by the birds, important staging areas that birds use as stopover points in their journey, and on the places where they dwell while in India.

Of some 200 species of wild birds that migrate long distances to come to India, the metal bands have been recovered from only 40 to 50 species and sufficient band recoveries to establish their migratory paths exist for less than 20 species, according to S. Balachandran of the BNHS who has tagged thousands of birds over the years. The band recovery rate is only 1 per cent for all birds tagged in India and many of the bands have been recovered by Russian hunters, he says.

So, in order to collect information about more species of birds, a large number of birds had to be tagged on a continual basis, points out Dr. Balachandran. But while Britain has a few thousand people, mostly volunteers, who have been trained in banding birds and are licensed to do so, in India there were only about 20 persons at the height of the banding activities. Now there were only a handful of people who were experienced in banding birds and, with limited government funding, only about 20,000 birds had been tagged since 1992, says Dr. Balachandran.

A long-term banding programme supported by the Union Government is needed, says Asad Rahmani, director of BNHS. Since banding required the careful capture of wild birds, such a programme could become the basis for the monitoring and surveillance of wild birds. The birds caught for banding could be given a quick health check and have samples taken from them for laboratory analysis. "We will be happy to involve veterinary doctors [in the banding programme] and collaborate with them in the surveillance [of migratory birds]," he added.

There is now a more attractive alternative to using metal bands — coloured plastic bands or flags that can be fixed to birds' necks or legs. The colour tells bird-watchers equipped with binoculars or telescopes where a bird was tagged. So the birds do not have to be captured or killed in order to recover the bands. The colour-coded markers have revolutionised the study of migratory movements of wild water birds in several regions of the world, points out Taej Mundkur of Wetlands International.

Call for colour scheme

But the use of such bands requires a suitable colour scheme agreed on by all countries forming a "flyway," the broad swath of territory often extending thousands of kilometres that wild birds use in the course of their annual cycle of migration. Countries of the "East Asian Australasian Flyway" have established a colour-banding scheme for some water birds in that region. A similar scheme was needed for the "Central Asian Flyway" that spans some 30 countries from the Arctic to the Indian Ocean as well as adjacent regions, says Dr. Mundkur. The Central Asian Flyway Action Plan, which was finalised at an international meeting in New Delhi in June 2005 by the Ministry of Environment and Forests under the auspices of the Convention on Migratory Species, could provide an appropriate framework for promoting a coordinated approach for these colour-banding activities, he adds.

"We need a structured bird banding programme to understand ongoing changes in bird migration," argues K.S. Gopi Sundar, principal coordinator of the Indian Cranes and Wetlands Working Group. Changes in habitat conditions and land use were having an impact on bird migration that needed to be understood. Global warming too appeared to be already having an effect with, for instance, certain species of cranes now opting to spend the winter in Uzbekistan instead of migrating south. It was important that data and results from bird banding be properly peer-reviewed and made easily accessible over the Internet.

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