15 April 2010
By Dipannita Das
Scientists Tracked International Migration Routes For 2 Yrs
A study carried out by the Bombay Natural History Society (BNHS) has revealed that migratory birds in the country were not carriers of the highly pathogenic avian influenza (HPAI) H5N1 virus.
BNHS scientists tracked the international migration routes of priority waterbird species in India and the Central Asian Flyway during the last two years before arriving at this conclusion.
S Balachandran, assistant director, BNHS, and leading bird expert told TOI that no H5N1 antibodies were found in the migratory birds in the country. ”More than 2,000 wild bird samples were tested at the High Security Animal Disease Laboratory (HSADL) in Bhopal for HPAI virus H5N1. All the results received, ie 90%, are negative.”
The study was sponsored by the Food and Agriculture Organisation (FAO) of the United Nations in 2008. Veterinary biologist Scott Newman of FAO was the international co–ordinator of the project.
”The process involved capturing and marking higher risk migratory waterbird species with BNHS–numbered metal bands, colour neck bands and platform transmitter terminals (PTTs). These birds were tracked and samples were collected from them to test for avian influenza,” Balachandran said.
The first phase of the PTTfitting programme was carried out in December 2009 at Chilika lake in Orissa and Koonthankulam wetland complex, Tamil Nadu. In all, 72 high–risk migratory ducks and eight species of geese were fitted with satellite transmitters during the programme.
”During the second phase of the satellite transmitter fitting programme, eight PTTs were fitted on bar–headed geese at Koonthankulam which took the number of bar–headed geese marked with PTTS to 25,” he explained.
”The wetlands where the migratory birds had moved and stayed more than 10 days, nearby wetlands and the poultries in a 20–km radius of the wetland were observed,” said Balachandran. ”The birds were tracked using Global Positioning System (GPS) and their routes plotted. The birds were monitored at the regular wintering sites in Chilika (Orissa), Assam, West Bengal and Tamil Nadu. Surveys were also carried out in the surrounding wetlands of Maharashtra, Chhattisgarh, Madhya Pradesh and Andhra Pradesh.”
Balachandran said that the survey documented the existence of a migratory connection between Indian wintering grounds and the birds’ breeding grounds in Tibet, China and Mongolia and provides new insights into the ecology of these species.
”The northward movement of PTT–fitted bar–headed geese from Koonthankulam, Tamil Nadu, and Chilika Lake, Orissa, have proved that the barheaded geese wintering in India are from the breeding population of China and Mongolia. We also established that these geese moved through the highly pathogenic avian influenza outbreak areas of West Bengal,” he said.
”Overwintering or summering of long distant migrant ducks in India was recognised through tracking. The study showed that none of the organised poultries within the 20–km radius of the wetlands were affected by HPAI,” he added.
An interesting sidelight of the study was that one of the geese tracked from Koonthankulam to northern Mongolia travelled over 5,900 km during its spring passage, one of the longest distances recorded.
- A total of 68 poultries in seven states within a 20–km radius of the wetlands were observed.
- Most of the areas (wetlands, farmlands) located along the routes taken by the Chilika birds during their northward migration, were largely dry and the wild bird numbers were low in a majority of the wetlands surveyed.
- The importance of multipurpose dams and irrigation reservoirs during the spring passage of the wintering waterbirds of India was recognised during the study.
- In Maharashtra, the farmlands utilised by the Northern Pintail was assessed in Jalna. Only a few paddy fields were seen around two irrigation tanks. The areas beyond the irrigation tanks were dry. Less than 600 wild birds were recorded from both wetlands.