Pallid harrier in flight
Natural Research is supporting a study of the globally vulnerable pallid harrier (Circus macrourus) in India. Pallid harriers have shown a drastic population decline during the last decades, both in their breeding and wintering grounds. The conversion of grasslands and barren fields into agricultural fields and plantations has probably resulted in loss of their foraging, breeding and roosting habitats. Agricultural practices, including pesticide use, have also probably contributed indirectly to their decline by affecting their prey base, especially rodents, grasshoppers and small land birds.
Further research into the wintering ecology of this vulnerable species and the identification of migratory routes and links between breeding and wintering populations were highlighted as critical and urgent priorities in the Biodiversity Action Plan for the species. Much of the global wintering grounds for pallid harriers are in India.
A pilot study in India by A. Verma has reported on the locations of some important roost sites in the country, as well as on the variation in numbers and population structure at those roost sites across the winter. Grassland habitats in India are under severe pressure from agricultural encroachment and intensification and there is a critical need to understand their importance for harriers and other wildlife. Moreover, there are few data on the behaviour of foraging pallid harriers, including the preference for, and profitability of, hunting over different habitat-types. Our current project has used satellite telemetry to help understand the movements of pallid harriers within and outside the country.
In addition, collaboration with ATREE (Ashoka Trust for Research in Ecology and the Environment) is underway to map natural grasslands and other harrier habitats across India, using remotely-sensed data. These results will:
inform the search for the major wintering areas in the field,
aid interpretation of telemetry data,
help monitor grassland habitat loss over the country.
Click here to see what we are doing on the pallid harrier's breeding grounds.
We plan to catch more birds in early winter 2008-2009 in order to track possible winter movements across India and identify their breeding grounds.
Principal investigators and collaborators: Natural Research Ltd, UK; Dr Bea Arroyo, Instituto de Investigación en Recursos Cinegéticos, Ciudad Real, Spain; Dr Ashok Verma, Wildlife Institute of India, India; Dr T. Ganesh, ATREE Bangalore, India; Chaitanya Krishna, MsC, ATREE Bangalore, India; Thomas Cornulier, Institute of Biological and Environmental Sciences, Aberdeen University, Aberdeen, UK.
Photos by T. Cornulier