Extinct in ten years, vultures decline quicker than the dodo
Wednesday 30 April 2008
Asian vultures face extinction in the wild within a decade without urgent action to eliminate the livestock drug that has caused their catastrophic decline, scientists are warning. Their decline has been quicker than that of any other wild bird, including the dodo.
A new study shows that the population of oriental white-backed vultures is dropping by more than 40 per cent every year in India where it has plunged by 99.9 per cent since 1992. Numbers of long-billed and slender-billed vultures together, have fallen by almost 97 per cent in the same period.
Conservationists say that banning the retail sale of the veterinary drug diclofenac and constructing more captive breeding centres is the only way to save the birds.
Manufacture of the veterinary form of the drug, as an anti-inflammatory treatment for livestock, was outlawed in India in 2006, but it remains widely available. Furthermore, diclofenac formulated for humans is being used to treat livestock.
Scientists counted vultures in northern and central India between March and June last year. They surveyed the birds from vehicles along more than 160 sections of road totalling 18,900 kilometres in length. Their study followed four previous counts, the last in 2003.
In a paper, published today (April 30th) in the Journal of the Bombay Natural History Society, they say “the oriental white-backed vulture is now in dire straits with only one thousandth of the 1992 population remaining.
“All three species could be down to a few hundred birds or less across the whole country and thus functionally extinct in less than a decade…It is imperative that [diclofenac] is removed completely from use in livestock without any further delay to avoid the extinction of the three vulture species,” they add.
The scientists believe that numbers of oriental white-backed vultures in India could now be down to 11,000 from tens of millions in the 1980s. Populations of long-billed and slender-billed vultures have dropped to around 45,000 and 1,000 birds respectively.
Vulture numbers may be even lower than the authors’ estimate because many of the sites used for their study were in or near protected areas, where the threat from diclofenac may be lower.
The lead author, Dr Vibhu Prakash, of the Bombay Natural History Society, said “Efforts must be redoubled to remove diclofenac from the vultures’ food supply and to protect and breed a viable population in captivity.”
Principle Investigator and co-author, Dr Andrew Cunningham of the Zoological Society of London, added, “These survey results show that imminent extinction looms for at least three species of vulture in India. Captive breeding is their last hope, so we are delighted that one of these species, the Oriental white-backed vulture, has successfully been bred this year in one of the captive breeding centres.”
Co-author, Dr Richard Cuthbert, of the RSPB, said “Time has almost run out to prevent the extinction of vultures in the wild in India. The ban on diclofenac manufacture was a good start but a ban on the sale of diclofenac and other drugs known to cause kidney failures in vultures is vital.”
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Notes to editors
- Dr Andrew Cunningham is available for interview (including on location at ZSL London Zoo) – contact Alice Henchley (ZSL Senior Press Officer) to arrange details.
- High resolution photos of vultures and the conservationists working in the field are available – contact Alice Henchley to request electronic copies.
- Founded in 1826, the Zoological Society of London (ZSL) is an international scientific, conservation and educational charity: our key role is the conservation of animals and their habitats. ZSL runs ZSL London Zoo and ZSL Whipsnade Zoo, carries out scientific research in the Institute of Zoology and is actively involved in field conservation in over thirty countries worldwide. www.zsl.org
- The paper published on 30th April 2008: Recent changes in populations of resident Gyps vultures in India, V Prakash (Bombay Natural History Society), RE Green, DJ Pain (RSPB), SP Ranade, S Saravanan, N Prakash, R Venkitachalam (BNHS), R Cuthbert (RSPB), AR Rahmani (BNHS), AA Cunningham (Zoological Society of London); Journal of the Bombay Natural History Society, April 2008.
- A total of 165 sections of road, totalling 18,890 kilometres in length, were used for the 2007 study. A car was driven along each section with an observer counting vultures seen on the ground and in the sky within 500m either side of the road.
- The World Conservation Union classifies all three affected vulture species (the Oriental white-backed, the Indian long-billed and the slender-billed vulture) as critically endangered, the highest risk category short of extinct in the wild.
- A study in 2004 confirmed that diclofenac was the main, if not the only, cause of vulture declines. The birds die of kidney failure after eating the carcasses of animals that have died within a few days of treatment with diclofenac (Oaks, J.L., et al. (2004) Nature 427, 630-633). There is also evidence that similar drugs, carprofen and flunixin, cause lethal kidney failure.
- Three captive breeding centres have been built so far in India: in Harayana, northern India, where 120 vultures are housed, in West Bengal, holding 52 vultures, and in Assam, holding 10 vultures. Two additional centres are operational in Nepal and Pakistan. These centres aim to hold viable populations of all three species.
- The UK Government’s Darwin Initiative has helped to fund research and is contributing funds to the captive breeding programme. Defra’s Darwin Initiative draws on a wealth of biodiversity expertise within the UK to help protect and enhance biodiversity around the world. Since its launch in 1992, the Darwin Initiative has committed over £60million to 464 projects in more than 100 countries. Further details on the Darwin Initiative can be found at Darwin Initiative .
- The captive breeding programme has been funded by the Darwin Initiative, the National Birds of Prey Trust, the RSPB, the Zoological Society of London and the Indian State Government of Haryana.
Additional Background Information
- The Oriental white-backed (or white-rumped) vulture Gyps bengalensis is up to 85cm long, with a wing span of between 205 and 220cm. Adults are black with a white head and neck and short bill. The bird is sociable and used to breed in very large colonies. Now, they nest in trees in small colonies.
- The Indian long-billed vulture, Gyps indicus, is robust in appearance, more than 90cm long with buff back, white neck and yellowish bill. It is found near cultivated areas, often with white-backed vultures. It now nests in small colonies on steep cliffs and ruins. In the early 1990s, there were colonies of up to 1,000 birds.
- The slender-billed vulture, Gyps tenuirostris, is between 80 and 95cm long, a thinner vulture, mostly brown and scruffy looking. It nests in large trees and is the rarest of the three Asian vulture species.
- Other studies showed that just 0.8 per cent of livestock carcasses needed to contain a lethal dose of the drug to cause such rapid declines (Green e e t al. (2004) Diclofenac poisoning as a cause of vulture population declines across the Indian subcontinent. J. Appl. Ecol. 41: 793‑800) and that a high enough proportion of carcasses of cattle available to vultures in India contained sufficient diclofenac to entirely account for the declines (Green et al. (2007) Rate of decline of the oriental white‑backed vulture Gyps bengalensis population in India estimated from measurements of diclofenac in carcasses of domesticated ungulates. PloS One. 2(8):e686.doi:10.1371/journal.pone.0000686).
- A replacement drug, meloxicam, was shown to be safe for vultures and other scavenging birds and effective as a livestock treatment two years ago, but more cattle are still treated with diclofenac than meloxicam.
- The manufacture of veterinary formulations of diclofenac was banned by the Drug Controller General of India in August 2006, after meloxicam was shown to be a viable alternative, because of the effect of diclofenac on vultures.
- The Parsi community is having to find other means of body disposal – they regard water, land and air as sacred so other, more conventional, methods are inappropriate.
- Feral dog numbers have increased during the vulture decline, presenting possible additional public health threats through dog bites and diseases such as rabies.
- In Nepal efforts are underway to protect wild populations through the provision of safe food and to replace stocks of diclofenac with meloxicam, which sells for the same price as diclofenac. Nepalese authorities halted the domestic manufacture and import of diclofenac in August 2006.
- Populations of oriental white-backed and slender-billed vultures are also found in Myanmar, Bangladesh, Bhutan and Cambodia, but they are much smaller than those in India. Oriental white-backed and long-billed vultures are found in Pakistan and white-backed and slender-billed in Nepal, but populations in these two countries have declined in a similar way to those in India.
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