Thursday, 18 July, 2024

Disappearing Vultures Of Nepal


Dr.Kedar Karki

Vultures are scavengers which feed on the carcasses of large animals, thus playing important role in cleaning of the environment. Vultures have been described in Hindu epic Ramayana as Jatayu while sacrificed himself while saving Sita from the clutches of Ravana. The followers of the Zoroastrianism have traditionally been dependent on vultures for disposal of their dead bodies. Therefore, for several centuries vultures have been providing a crucial ecosystem service for the Parsi people.
Environmental Role
Nepal is home to around 15,000 to 20,000 vultures. White-rumped and slender-billed vultures are among them. The vultures are the birds that are seen scavenging on carcasses of dead animals and human dead bodies in the sky burials. They play an important role in maintaining clean environment through rapid consumption of animal carcasses.
Studies found that around 90 per dent population of white-rumped and slender-billed vultures had declined from 1995 – 2009. In the recent years, the government and the private sector have made efforts towards vulture conservation. For example, vulture breeding centres have been established, vulture restaurant have built and vulture conservation foundations are set up.
Vultures are the natural cleaners of the environment. They feed on dead decaying animals thereby enhancing the process of mineral return to the soil. Moreover, by disposing the dead bodies they check the spread of infectious diseases. In absence of vultures the population of animals like rodents and stray dogs tend to increase leading to the spread of rabies.
There are nine different species of vultures are in South Asia. Nepal houses six resident vulture species They are white-rumped vulture (Gyps bengalensis), slender-billed vulture (Gyps tenuirostris), Egyptian vulture (Neophron percnopterus), red-headed vulture (Sarcogyps calvus), Himalayan griffon (Gyps himalayensis), and Lammergeier Vulture (Gypaetus barbatus). One winter visitor Cinereous vulture and one passage migrant Eurasian griffon are also found in Nepal.
According to the International Union for Conservation of Nature (IUCN), an endangered species is that which is in danger of extinction and whose survival is unlikely if the causal factors continue to be operating, whereas the species which is facing extremely high risk of extinction in the wild in immediate future is known as Critically Endangered species. Near Threatened species is that species which is not Critically Endangered, Endangered, Vulnerable or Conservation Dependent but is close to qualifying for Vulnerable. Least Concern species is the one which is not Critically Endangered, Endangered or Vulnerable and does not qualify for Conservation Dependent or Near Threatened.
The main threats to the survival of vultures in Nepal include the veterinary use of analgesic Diclofenac, habitat destruction, pesticide pollution, slow breeding rate, paucity of carcasses, feeding of the poisoned carcasses and lack of legal protection. Studies suggest that, Diclofenac, an anti-inflammatory drug widely used to treat livestock is the prime cause of vulture’s decline. Thus, vultures are exposed to Diclofenac when they feed carcasses of livestock containing toxic residues of the drug. There are also some other causes such as loss of forests and lack of food that pose survival threats.
Diclofenac is effective in treating joint pains of cattle. Thus the use of Diclofenac is widespread as pain reliever in cattle in India. Since kidneys take a lot of time to flush this drug out of the system, hence even after the death it remains in the body of cattle. Once vultures consume the Diclofenac contaminated flesh, their kidneys stop functioning, leading to death.
Pesticide pollution is also a threat to Vultures in Nepal. The chlorinated hydrocarbon DDT (Dichloro Diphenyl Trichloroethane) used as pesticide enter the body of Vultures through food chain where it affects the activity of estrogen hormone, as a result of which the egg shell is weakened consequently the premature hatching of egg takes place causing the death of the embryo. As a vultures generally lays a single egg in a breeding season, their breeding rate is naturally slow.
Use of poisoned carcasses as baited by human beings to kill cattle-marauding carnivores is also a threat to Vultures in Nepal. Accidental consumption of such poisoned carcasses by Vulture leads to their death.
Poachers poison wild animals such as elephant, tiger, rhinoceros, deer and bear to take away the tradable parts such as hide, tusk, musk, antler, horn and bile. Feeding of the carcasses of these poisoned animals can be fatal.
Negative consequences
Disappearing of ecologically important vultures is a matter of concern. In places where vultures were in abundance, populations of feral dogs have decreased. The increase in the number of dogs has been proportional to the decline in the number of vultures. With increase in number of dogs the incidence of rabies-related deaths has also increased.
The escalating incidence of leopard’s assault in villages of Nepal is due to decline in vulture population. In fact, the multiplication of feral dogs has caused a multiplication of leopards feeding on those dogs. There the leopards invade the human settlement areas to prey on the dogs. These often results in attacks on humans.
Though the government has banned the use of culprit drug Diclofenac by recommending Meloxicam as its substitute, the former is still sold illegally and is frequently being used by the cattle farmers in Nepal. Thus the mortality of vultures continues in Nepal.
Conservation Measures
Disappearing of vultures is a matter of serious concern and needs immediate action to conserve these valuable birds. There is a need to evolve an effective substitute of diclofenac, and the present available substitute meloxicam needs to be subsidised. Captive-breeding programme with aim to reintroduce vultures into the wild need to be launched on large scale. Efforts should be made to protect and conserve the Near Threatened and Least Concern species of Vultures in Nepal. Vulture feeding stations should be set up by supplying poison-free food, clean water, bone chips and perches. This could be the best in situ conservation tool for the protection of these scavenging birds. Degraded habitats of Vultures need to be restored. There should be a complete ban on the use of chlorinated hydrocarbons like D.D.T.
(Dr. Karki is a retired veterinary officer)