Populations of oriental white-backed vulture (Gyps bengalensis), long-billed vulture (Gyps indicus) and slender-billed vulture (Gyps tenuirostris) crashed during the mid-1990s throughout the Indian subcontinent. Surveys in India, initially conducted in 1991–1993 and repeated in 2000, 2002, 2003 and 2007, revealed that the population of Gyps bengalensis had fallen by 2007 to 0.1% of its numbers in the early 1990s, with the population of Gyps indicus and G. tenuirostris combined having fallen to 3.2% of its earlier level. A survey of G. bengalensis in western Nepal indicated that the size of the population in 2009 was 25% of that in 2002. In this paper, repeat surveys conducted in 2011 were analysed to estimate recent population trends. Populations of all three species of vulture remained at a low level, but the decline had slowed and may even have reversed for G. bengalensis, both in India and Nepal. However, estimates of the most recent population trends are imprecise, so it is possible that declines may be continuing, though at a significantly slower rate. The degree to which the decline of G. bengalensis in India has slowed is consistent with the expected effects on population trend of a measured change in the level of contamination of ungulate carcasses with the drug diclofenac, which is toxic to vultures, following a ban on its veterinary use in 2006. The most recent available information indicates that the elimination of diclofenac from the vultures’ food supply is incomplete, so further efforts are required to fully implement the ban.

SummaryPopulations of the White-rumped Vulture Gyps bengalensis, Indian Vulture G. indicus and Slender-billed Vulture G. tenuirostris declined rapidly during the mid-1990s all over their ranges in the Indian subcontinent because of poisoning due to veterinary use of the non-steroidal anti-inflammatory drug diclofenac. This paper reports results from the latest in a series of road transect surveys conducted across northern, central, western and north-eastern India since the early 1990s. Results from the seven comparable surveys now available were analysed to estimate recent population trends. Populations of all three species of vulture remained at a low level. The previously rapid decline of White-rumped Vulture has slowed and may have reversed since the ban on veterinary use of diclofenac in India in 2006. A few thousand of this species, possibly up to the low tens of thousands, remained in India in 2015. The population of Indian Vulture continued to decline, though probably at a much slower rate than in the 1990s. This remains the most numerous of the three species in India with about 12,000 individuals in 2015 and a confidence interval ranging from a few thousands to a few tens of thousands. The trend in the rarest species, Slender-billed Vulture, which probably numbers not much more than 1,000 individuals in India, cannot be determined reliably.

Use of the veterinary drug diclofenac is responsible for bringing three species of Gyps vultures endemic to South Asia to the brink of extinction, and the Government of India banned veterinary use of the drug in May 2006. To evaluate the effectiveness of the ban we undertook surveys of > 250 veterinary and general pharmacies in 11 Indian states from November 2007 to June 2010. Twelve different classes of non-steroidal anti-inflammatory drugs (NSAIDs) were purchased from 176 pharmacies. Other than meloxicam (of negligible toxicity to vultures at likely concentrations in their food), diclofenac and ketoprofen (both toxic to vultures), little is known of the safety or toxicity of the remaining nine NSAIDs on sale. Meloxicam was the most commonly encountered drug, sold in 70% of pharmacies, but 50% of the meloxicam brands sold had paracetamol (acetaminophen) as a second ingredient. Diclofenac and ketoprofen were recorded in 36 and 29% of pharmacies, respectively, with states in western and central India having the highest prevalence of diclofenac (44–45%). Although the large number of manufacturers and availability of meloxicam is encouraging, the wide range of untested NSAIDs and continued availability of diclofenac is a major source of concern. Circumvention of the 2006 diclofenac ban is being achieved by illegally selling forms of diclofenac manufactured for human use for veterinary purposes. To provide a safer environment for vultures in South Asia we recommend reducing the size of vials of diclofenac meant for human use, to increase the costs of illegal veterinary use, and taking action against pharmaceutical manufacturers and pharmacies flouting the diclofenac ban.

Summary The catastrophic declines of three species of ‘Critically Endangered’ Gyps vultures in South Asia were caused by unintentional poisoning by the non-steroidal anti-inflammatory drug (NSAID) diclofenac. Despite a ban on its veterinary use in 2006 (India, Nepal, Pakistan) and 2010 (Bangladesh), residues of diclofenac have continued to be found in cattle carcasses and in dead wild vultures. Another NSAID, meloxicam, has been shown to be safe to vultures. From 2012 to 2018, we undertook covert surveys of pharmacies in India, Nepal and Bangladesh to investigate the availability and prevalence of NSAIDs for the treatment of livestock. The purpose of the study was to establish whether diclofenac continued to be sold for veterinary use, whether the availability of meloxicam had increased and to determine which other veterinary NSAIDs were available. The availability of diclofenac declined in all three countries, virtually disappearing from pharmacies in Nepal and Bangladesh, highlighting the advances made in these two countries to reduce this threat to vultures. In India, diclofenac still accounted for 10–46% of all NSAIDs offered for sale for livestock treatment in 2017, suggesting weak enforcement of existing regulations and a continued high risk to vultures. Availability of meloxicam increased in all countries and was the most common veterinary NSAID in Nepal (89.9% in 2017). Although the most widely available NSAID in India in 2017, meloxicam accounted for only 32% of products offered for sale. In Bangladesh, meloxicam was less commonly available than the vulture-toxic NSAID ketoprofen (28% and 66%, respectively, in 2018), despite the partial government ban on ketoprofen in 2016. Eleven different NSAIDs were recorded, several of which are known or suspected to be toxic to vultures. Conservation priorities should include awareness raising, stricter implementation of current bans, bans on other vulture-toxic veterinary NSAIDs, especially aceclofenac and nimesulide, and safety-testing of other NSAIDs on Gyps vultures to identify safe and toxic drugs.

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