Dire State of Asian Vultures warns of Complacency in improved kite fortunes in UK
Following the article by Ngaio Richards and the update above I thought it would be relevant to give a bit more information on the massive crisis facing vultures in Asia.
The following is an edited account of information provided on the website of Birdlife and is reproduced with kind permission.
Populations of three Gyps vulture species (White-backed, Long-billed, and Slender-billed) in parts of their ranges in South Asia fell by more than 95 percent in just three years in the 1990s, and all are now classified as Critically Endangered. Prior to this decline, White-rumped Vulture was considered to be one of the commonest large birds of prey in the world. Unless major steps are taken, all three species will soon be facing extinction.
The cause of the decline was difficult to pin-point and initially work was concentrated on potential infective agents. A frequently reported symptom was a drooping head, the neck dangling almost as if broken. Afflicted birds seemed unable to recover and were soon found dead. One frequent finding in dead vultures from India and Pakistan has been the presence of severe gout in the birds. The declines have taken place across all regions and habitats in India, including protected areas and unprotected areas. No other scavenging species appear to have undergone similar population crashes, and scavengers such as feral dogs have increased in numbers at many sites, as food has become more available.
A breakthrough in the race to find a cause was announced at a meeting in Hungary on 20th May 2004. Lindsey Oaks, a scientist at Washington State University working with the Peregrine Fund, presented information on the causes of death of a number of vultures from three colonies in Pakistan. These researchers found that birds with gout had high levels of diclofenac, a recently introduced and widely used non-steroidal anti-inflammatory drug (NSAID), known to be toxic to the kidneys of mammals. Dead vultures that did not have gout had undetectable levels. It appears that this drug, used for human medicine for decades, has also been used in veterinary medicine in India and Pakistan in recent years. Vultures appear to have been exposed to the drug through scavenging livestock carcasses containing residues. Further investigation showed that diclofenac was fatal to vultures at 10 percent of the recommended mammal dose. Tissue residues in livestock treated at the labelled dose rate were sufficient to cause gout and death in vultures. Furthermore, as few as one in 760 livestock carcasses containing diclofenac at a dose lethal to vultures would be sufficient to cause the observed decline in vulture numbers (30% per year). Clearly, even small-scale usage of the drug can have catastrophic consequences.
This is clearly an ecological disaster but it also has a direct human impact. Vultures play a key role in removing carcasses thereby reducing the risk of disease and helping with sanitation. With the vultures gone, carcasses are likely to take much longer to be stripped, increasing the risk to health. Feral dogs are filling the scavenging void, and their growing numbers also increase risks to human health and safety: they are carriers of rabies.
The birds play a part in the funerary rites of some religious groups, including the Parsees in India: bodies are exposed to be stripped by vultures. In some parts of the country vultures are now so scarce that cremation is being used as an alternative to this traditional celestial burial.
The discovery that a drug is responsible for the declines offers some hope for the vultures, but also serves as a wider warning of the risks that pharmaceuticals can pose to wildlife and human populations.
The Indian government has confirmed their intention to phase-out diclofenac within the next six months. Dr Asad Rahmani, Director of Bombay Natural History Society (BirdLife in India) added, "In taking the decision to phase out diclofenac, Prime Minister Mr Manmohan Singh has taken the most important step yet to save these fast-disappearing vultures. However, the battle is not yet over. We have to develop conservation breeding centres as a further safeguard for these magnificent lords of the sky."
