Migrating grassland raptors: population change in harriers across space and time
Harriers are migratory raptors that roost on the ground in large numbers in tall grasslands. However, with the disappearance of grasslands in the country, the roosts of many of these birds are affected. This Department of Science and Technology project attempts to identify such roosts from historical records and field visits, monitor their population in such roosts and track how the birds move at the individual and population level across the subcontinent. This information, which is expected to show how these birds use dynamic grasslands and scrub habitats in a human-dominated agriculture-grassland matrix, would have a bearing on conservation science. The project has revealed a significant decline in the population of harriers in India, more significantly in the Rollapadu Bustard Sanctuary in Andhra Pradesh, which once had the second largest roost site in India. The project also identified lacunae in the monitoring of several ecological parameters which could help in understanding the impact of pesticide, grassland transformation, agriculture intensity, and what happens in their breeding grounds apart from socio-ecological drivers of change. The project has initiated studies along these lines. In addition to its findings, the project also addressed the strict regulations in allowing advanced tracking devices to be fitted on animals to study animal migration.