Pune based NGO Ela Foundation and the National Institute of Virology (NIV) have recently published a research paper that analyses the cause of drastic fall in the vulture population of India. While many believe the main reason for the deaths is use of Diclofenac, a chemical that is fatal to the birds, the research papers suggests other reasons too including electrocution.
“It has been reported that the two species of vultures, the Oriental White-backed Vulture and the Long-billed Vulture Gyps indicus, have declined in population by more than 90 per cent throughout India. It was believed that morbid birds exhibit signs of illness (neck drooping syndrome) for approximately 30 days prior to death. We undertook further investigations on this bird, as vultures are threatened with extinction and, therefore, it is of utmost importance to investigate the causes of morbidity and mortality in these birds,” said ornithologist Satish Pande from the Ela Foundation, which is also the principal investigator.
Here are the six top reasons according to the researchers for the rapid decline of vulture population in India.
The researchers had rescued an Oriental White-backed Vulture, Gyps bengalensis, which was found in an open field at Bhangaon village in Shrigonda taluka. They conducted studies on the bird and found that it was emaciated but was not poisoned.
Shailesh Pawar, Scientist-B, Avian Influenza, NIV, said, “Blood, serum, cloacal, faecal and tracheal swabs of the bird were collected and tested at the National Institute of Virology (NIV). There was no evidence of blood parasites or blood infection like malaria or Avian Influenza viruses.”
When the bird was eventually released, it unfortunately got electrocuted from electricity wires almost 60 km away from the point of release. The researchers thus believe that electrocution, a reason hitherto not mentioned might be leading to more number of vulture deaths.
“Electrocution from overhead electricity wires is another reason cited in the research, because the larger the bird and its wing span, the higher the chances of electrocution. Some other species that are threatened due to electrocution are Great Indian Bustard, Saras Crane and some species of Eagles,” said Pande.
2. Food Shortage
Another reason for the decline in vulture population quoted by the experts is shortage of food. This is because the central government has given a directive to villagers to bury the carcasses of dead animals in order to keep villages clean. While the effort is good, the lack of animal carcasses leaves the vulture hungry and without food.
“One major reason is shortage of food. As per government’s directions under theGram Swachata Abhiyan, livestock carcasses have to be buried and not left outside. This has led to a major reduction in food for vultures.” Said Pande.
The people of Ela Foundation do not believe that this chemical is harming the vultures as much as projected. This is because the shelf life of Diclofenac is 6 hours and if the vultures do eat the carcasses of animals who have been administered the drug, the chances of the chemical reaching their body is very less.
Pande believes that though the use of the chemical may be one of the causes for the vulture deaths, it may not be the sole reason as the drug has also been banned from use and its usage has reduced if not totally stopped.
“Diclofenac led them to be afflicted with a disease called Gout, leading to organ dysfunction. The authorities therefore banned the drug. But the vultures are on the decline, more so since 1985. Diclofenac poisoning is therefore not the only cause. Only few vultures have hitherto been known to have died of diclofenac poisoning. The decline has therefore been due to a number of causes,” said Pande.
Some of the vultures they studied were found to be suffering from Malaria. This had led them to conclude that this too may be one of the reasons vultures are dying in the wild.
Many farmers spray cattle carcasses with the pesticide such as Organo-chlorineand Organo-phosphorous to prevent them from spreading foul odour. This pesticide infested carcass may be eaten by the vulture leading to its death. The scientists have found instances where hundreds of vultures have died this way.
6. Lack of Nesting Trees
Some species of vulture like the Oriental White-backed Vulture prefer to make their nest on coconut trees. But when the trees are chopped off, the vultures lose their home. Some trees may also wither away due to the frequent vulture droppings on the trees, and therefore many times they are cut even though they are healthy.
There are therefore number of reasons leading to decline in vulture population. If the concept of vulture restaurants already started in few locations in India is taken to various parts of the country, it may serve as a beneficial and safe way to provide vultures with food and help them live longer.
- Atula Gupta