Kangra Valley in Himachal Pradesh is a unique spot in India—it is home to one of the largest wild populations of the critically endangered white-rumped vulture (Gyps bengalensis) in the country. The Kangra Valley extends from the foot of the Dhauladhar range to the south of river Beas. Landscapes in Kangra range from dry canyons and streams to subtropical forest, wetland, high altitude forest and meadows.
Historically, a sky full of vultures soaring high above a carcass was a common sight. In the 1990s, a rapid and significant population decline of three Gyps vultures in south Asia decreased their population by about 95%. The main contributing factor was the extensive use of drugs such as diclofenac as an anti-inflammatory drug to treat livestock, on which vultures fed. Diclofenac has been banned for veterinary use since 2006, but the vultures haven’t recovered as habitat loss and other threats still remain. Vultures are also slow-breeding birds, which means their population is still very small and may not survive another such adverse event.
My study area lies in and around Pong Dam Lake. The lake was created in 1975 across the river Beas in Himachal Pradesh, and has excellent biodiversity value. About 400 species of 100,000 birds make Pong their home during the migratory season, including the largest congregations of bar-headed geese globally, making it a wetland of international importance, and one of the four Ramsar sites in India.
I wanted to find out the reason behind the large population of vultures in the area—did it relate to habitat, food availability, elevation or slope? A few months after I started my fieldwork, covid-19 broke out. The Himachal Pradesh Forest department staff supported our work enormously and helped us carry on even in the pandemic. The department also established a vulture restaurant—a fenced site where carrion is deposited to attract the birds—which are crucial to conserve the critically endangered species. Understanding the habitat and the movement dynamics of vultures are necessary to understand the problem.
From December 2020, we started identifying the breeding areas and feeding sites as well as monitoring carcasses. Around January 2021, we had to stop work as there was a bird flu, or avian influenza, outbreak among the migratory birds at Pong Dam Lake. Himachal Pradesh along with Haryana, Rajasthan, Kerala and Madhya Pradesh reported cases of suspected avian influenza.
We changed tack to focus on the cause of bird mortality, and surveyed the ground. The forest department staff had observed the first dead birds, including bar-headed geese, on 28 December 2020. Soon, carcasses were being found daily in many parts of the reservoir. Around the same time, reports of mass mortality of poultry in a nearby farm came to be known. As per protocol, the forest department personnel started to collect the carcasses of dead birds in the reservoir and bury them. Samples sent to the ICAR-National Institute of High-Security Animal Diseases (NIHSAD) in Bhopal confirmed the cause of mortality as the highly pathogenic H5N1, the virus that causes avian influenza which primarily infects birds but, in some cases, can be transmitted to humans.
So, we were dealing not with one pandemic, but two! The forest department staff worked tirelessly to contain the outbreak and within a few months, they were successful. They removed every carcass as soon as it was detected to prevent further spread of the disease. What we really need is more research on the transmission routes of this virus, including on the role of the poultry trade and the release of captive reared-birds, in order to prevent such outbreaks.
By April, we were able to start our research on vultures again. We found many nesting sites of white-rumped vultures. In a way the pandemic had helped as tourism had stopped, and the pristine areas were undisturbed. For researchers, however, the pandemic has been a struggle. Fieldwork is essential for science but in the pandemic, most of us had to stay home or were unable to collect data even if we were on the field as we could not move around for fear of contracting or spreading the virus. It’s also important that funding agencies realise why we’ve all slowed down in the past two years and allow a reasonable time for follow-up. But now that many people are vaccinated, we can return to work, though we cannot make up for lost time.
Malyasri Bhattacharya is a researcher at the Wildlife Institute of India with interests in migratory biology, radio-telemetry studies and sensory biology research on birds. This series is an initiative by the Nature Conservation Foundation. To know more, join The Flock, a free newsletter on birds and nature awareness.