Andrew Routh, Chief Veterinary Officer of the Zoological Society of London is part of an international effort to reverse the dramatic decline of the griffon vultures in the Indian sub-continent. Here he explains to TTO readers what led to their decline and the measures being taken to reverse it

There was a time when vultures ranged across large areas of Asia, playing a vital role in both the ecosystem and in culture. As scavengers they had moved on. With changes in the environment and a growing human population, they became clearers of carcases of domestic animals and, indeed, of people. Carl Bock, in his book from 1884 “Temples and Elephants”, describes vultures attending funerals at Wat Saket, Bangkok. However, a century later in “Birds of Thailand”, Boonsong and Round described the oriental white-backed vulture (OWBV) and long-billed vultures (LBV) as essentially locally extinct. Changes in agricultural practices, loss of habitat and persecution had all contributed to their disappearance.

Elsewhere in Asia three of the griffon vulture species continued to be seen in large numbers. The OWBV was the most numerous large bird of prey on the planet. Division of the LBV into two species gave a numerically small population of slender-billed vultures (SBV) from Assam eastward, with gaps in distribution, to Cambodia. The LBV had a much larger population but was confined primarily to India.

The loss of vultures from key sites in India was first noted in the late 1990’s. Dr Vibhu Prakash, then a researcher and now project leader of the programme in India, documented the loss of a large colony of OWBV from the internationally-renowned wetland known to ornithologists worldwide as Bharatpur. Surveys were undertaken, in particular in India by the Bombay Natural History Society (BNHS). These confirmed that populations of all three species were falling at an unprecedented level, probably in excess of a rolling 50% per year.

Perhaps of greater concern was that the cause of the decline was unknown. The habitat was still there, with nesting sites now vacant and uneaten carcases now being scavenged by stray dogs (whose burgeoning population was soon leading to concerns about a parallel increase in risk of rabies). The Zoological Society of London (ZSL) was one organisation involved in the initial investigation of the mortalities. Birds were found dead, often in good condition but with evidence of kidney failure. This included deposits in the internal organs of the naturally-produced avian waste-product uric acid. Vultures found alive would recover following fluid therapy.

One study of vulture carcases, led by researcher Lindsay Oaks from the Peregrine Fund, produced a result. There was an absolute correlation between the finding of uric acid deposits in the carcases of vultures and tissue levels of a drug called diclofenac. Birds that had died of other causes, e.g. hitting power-cables, had neither the uric acid crystals nor the diclofenac.

With vultures now visibly vanishing from their previous strongholds and facing extinction and with an identified cause of the decline, the conservation world set about a rescue plan. In parallel with the need to remove and replace veterinary diclofenac there would have to be captive breeding centres set up, so that disappearance from the wild would not lead to the extinction of the three species.

The result has been a collaborative, international, effort under-pinned by the national and state governments in the range countries. Local non-governmental organisations (NGOs) include the BNHS in India and the National Trust for Nature Conservation (NTNC) in Nepal. From the UK, the Royal Society for the Protection of Birds (RSPB) have been key supporters of the programme in both countries, with ZSL extending its support to include provision of expertise and training at the captive breeding centres. The International Centre for Birds of Prey (ICBP) has been involved in aviary design and vulture care with, more latterly, training on egg incubation.

Diclofenac is a drug known as a non-steroidal anti-inflammatory drug or NSAID. It is used in humans for a range of conditions. (I was prescribed it for a bad back due to disc problems). Coincidental with the drug coming off patent was its production in Asia (though not Europe or the USA) for the veterinary market. The drug is used for the treatment of a number of conditions in domestic species including cattle, sheep and goats. For these it is both efficacious and safe. It is eliminated from these target species within several days of treatment, providing the patient lives. A proportion of them do not.

Its toxicity, at levels found in treated animal carcases, to a related vulture species in Africa has been demonstrated. And could this one drug have caused the decline? Computer-modelling proposes that it would take just one carcase in 250 to be contaminated to cause the decline. Surveys showed the actual figure to be one in 90 carcases.

Ongoing surveys of populations of vultures in the wild show both a continued decline and diclofenac residues in carcases. This fundamental scientific backing means the project must be divided into two prime areas of action.

Firstly, diclofenac needed to be removed from the veterinary and agricultural environment.  The governments in the range countries have reacted very positively to lobbying and advocacy. Diclofenac has been banned as a veterinary product in both India and Nepal. A replacement needed to be found. An informal survey of zoological collections around the world identified the NSAID meloxicam as one that had been used without fatalities to therapeutically treat vultures. Its safety was confirmed. The drug is now promoted as an alternative to diclofenac for domestic animals.

However, carcase surveys show that diclofenac continues to be used. Why might this be? Certainly there has been great faith in diclofenac. It has been difficult to encourage change, in particular when the alternative is more expensive. Thus, in the absence of veterinary diclofenac, the identical medical preparation is being used. It is hoped that with refinement and with greater volumes of production the price of meloxicam will fall to a level equivalent to that of diclofenac, leading to its greater use.

Secondly, captive-breeding centres needed to be established. Early on it was determined that the major conservation effort would remain in the vulture range countries. In India, three centres have been set up. They are in Haryana, West Bengal and Assam. The one centre in Nepal is on the edge of the national park at Chitwan.

There is a basic similarity to their function and design, having aviaries and support facilities. All are dedicated solely to vulture breeding and none are open to the public. Management of so many large vultures, (an adult can weigh in excess of five kilograms and have a wing-span in excess of two metres), presents a number of often costly challenges.  One is the feeding of the birds. All food animals have to be kept for seven days in case of recent medication with diclofenac.

Religious constraints mean that only goats can be fed at some of the centres and, in part related to the basic economics of supply and demand, goat meat can be expensive. Another challenge is the veterinary care of so many birds. My role within the project is to advise, either in situ or via email, on veterinary issues. I have run a total of three workshops for the local veterinary colleagues employed on the projects. One of our biggest worries is the risk of transmission of avian influenza to the birds at any of the centres.

During my recent visit to Nepal I was able to see an additional facility aimed at supporting vultures in the wild. A “vulture restaurant” has been set up in an agricultural community west of Chitwan. Aged cattle are held on a farm. When they die they are taken to a designated area and fed. At one end of the field is a bird hide.

The entrance fee for visitors goes back into the local community who are now strongly supportive of vulture conservation. Since the programme was initiated by Bird Conservation Nepal (BCN) the number of vultures in the area has increased, both through birds being drawn to a supply of food and through a number of birds nesting and breeding in the immediate area. The Wildlife Conservation Society (WCS) runs a similar project in Cambodia. Though these restaurants make a valuable contribution to vulture conservation there is always the risk that, as the birds are not confined, they could eat, with fatal consequences, a contaminated carcase away from the controlled environment of the restaurants.

This is a long-term project. Vultures do not breed until they are several years old and, unless the egg is taken for artificial incubation, a pair produces only one egg a year. When considering future genetic management, total numbers of vultures forming the founder captive population are low. Sourcing additional birds from a wild population now depleted by more than 99.99% is becoming increasingly difficult.

The good news is that already there have been birds bred at the centres in India, including the first ever SBV bred in captivity in the world. We also know that, through work on the Californian condor and the more closely-related European griffon vulture, scavenging raptors can be bred in captivity and successfully reintroduced to the wild. Previous work like this that leads us to believe that we, and the Thai workers who hope to breed the rare red-headed vulture, can be successful in reintroducing vultures back to a diclofenac-free wild. We hope the legacy of our work will be future generations being able to marvel again at these magnificent birds flying free.

To discover more go to –

Web-links – ZSL – www.zsl.org and try www.vulturerescue.org