Hem Sagar Baral

Diclofenac poisoning is widespread in declining vulture populations across the Indian subcontinent.

Recent declines in the populations of three species of vultures in the Indian subcontinent are among the most rapid ever recorded in any bird species. Evidence from a previous study of one of these species, Gyps bengalensis, in the Punjab province of Pakistan, strongly implicates mortality caused by ingestion of residues of the veterinary non–steroidal anti–inflammatory drug diclofenac as the major cause of the decline. We show that a high proportion of Gyps bengalensis and G. indicus found dead or dying in a much larger area of India and Nepal also have residues of diclofenac and visceral gout, a post–mortem finding that is strongly associated with diclofenac contamination in both species. Hence, veterinary use of diclofenac is likely to have been the major cause of the rapid vulture population declines across the subcontinent.

The race to prevent the extinction of South Asian vultures

Summary Gyps vulture populations across the Indian subcontinent collapsed in the 1990s and continue to decline. Repeated population surveys showed that the rate of decline was so rapid that elevated mortality of adult birds must be a key demographic mechanism. Post mortem examination showed that the majority of dead vultures had visceral gout, due to kidney damage. The realisation that diclofenac, a non-steroidal anti-inflammatory drug potentially nephrotoxic to birds, had become a widely used veterinary medicine led to the identification of diclofenac poisoning as the cause of the decline. Surveys of diclofenac contamination of domestic ungulate carcasses, combined with vulture population modelling, show that the level of contamination is sufficient for it to be the sole cause of the decline. Testing on vultures of meloxicam, an alternative NSAID for livestock treatment, showed that it did not harm them at concentrations likely to be encountered by wild birds and would be a safe replacement for diclofenac. The manufacture of diclofenac for veterinary use has been banned, but its sale has not. Consequently, it may be some years before diclofenac is removed from the vultures’ food supply. In the meantime, captive populations of three vulture species have been established to provide sources of birds for future reintroduction programmes.

Population trends of Critically Endangered Gyps vultures in the lowlands of Nepal

Three species of resident Gyps vulture are threatened with extinction in South Asia due to the contamination of domestic ungulate carcasses with the drug diclofenac. Observed rates of population decrease are among the highest recorded for any bird species, leading to total declines in excess of 99.9% for the Oriental White-backed Vulture Gyps bengalensis in India between 1992 and 2007. Vultures have declined in Nepal, but quantitative information on the rate and scale of decreases is unavailable. Road transect surveys for vultures, following the same route, methodology and timing, were undertaken in lowland areas of Nepal for seven years from 2002 to 2011. The seven survey transects followed Nepal’s East-West highway and covered 1,010 km in three years of the survey, and 638 km in the remaining four years. Slender-billed Vultures G. tenuirostris were very scarce, with a maximum of five individuals in 2002 and none recorded in 2010 and 2011. Oriental White-backed Vultures were most commonly recorded, but decreased from 205 to 68 birds over the survey period, with an estimated annual rate of decline of 14% a year. If population decreases commenced in Nepal in the same year as in India, then White-backed Vultures in Nepal have declined by 91% since the mid-1990s. Few resident Gyps vultures remained in Eastern and Central regions of Nepal, with just one, nine and six birds recorded in the three surveys that covered these regions. The majority of threatened Gyps vultures in lowland Nepal are now found in Western and Mid Western regions, where conservation efforts have been focused in the last six years. Removing veterinary diclofenac from across the country and continuing to manage effective “vulture safe zones” are essential to conserve Nepal’s remaining vulture populations.

Rapid population declines of Himalayan Griffon Gyps himalayensis in Upper Mustang, Nepal

Summary The population collapse of resident Gyps vulture species in South Asia, caused by the use of a veterinary drug diclofenac, has highlighted an urgent need to monitor numbers of other vulture species in the region. This study assessed population trends of Himalayan Griffon Gyps himalayensis in the mountainous region of Upper Mustang, Nepal, which is an important breeding area for the species. Vultures were surveyed in 2002, 2004 and 2005 by recording the number of birds sighted along 188 km of transects, and observing numbers of birds at breeding colonies. The number of birds recorded per day and per kilometre of transect declined by 67% and 70% respectively over the period of study. The number of active nests declined by 84% from 2002 to 2005. The veterinary drug diclofenac was available in pharmacies in the Mustang region. Young Himalayan Griffons, which migrate to the lowland areas of Nepal and, in increasing numbers to India, are highly likely to be subject to diclofenac poisoning. If this rate of population decline occurs throughout the Himalayan region, the conservation status of the species will need to be urgently reassessed.

Surveys of Himalayan Vultures (Gyps Himalayensis) in the Annapurna Conservation Area, Mustang, Nepal

ABSTRACT Populations of three species of lowland Gyps vultures (G. bengalensis, G. tenuirostris and G. indicus) in South Asia have declined precipitously over the last decade as a result of their feeding on diclofenac-contaminated livestock carcasses. Despite extensive studies on these three species, little is known about population trends in the highland species, Himalayan Vulture (G. himalayensis). We surveyed Himalayan Vultures in Nepal between 2001 and 2006. We found no evidence that their populations are facing the same magnitude of decline or threat as those of the three species of lowland Gyps vultures. We suggest that Himalayan Vultures may not be experiencing the same degree of diclofenac poisoning for a number of reasons, including possibly different foraging behaviors by Himalayan Vultures compared to the other Gyps vultures, and/or relatively lower use of diclofenac in the highland regions.

Population Structure and Annual Migration Pattern of Steppe Eagles at Thoolakharka Watch Site, Nepal, 2012–2014

ESTRUCTURA POBLACIONAL Y PATRONES ANUALES DE MIGRACION DE AQUILA NIPALENSIS EN EL PUNTO DE OBSERVACION THOOLAKHARKA, NEPAL, 2012–2014 Estudiamos la migracion este-oeste de la especie en peligro Aquila nipalensis en Thoolakharka, Nepal (elevacion 2050 m snm) desde mediados de septiembre hasta principios de diciembre en los anos 2012–2014, para estimar la estructura de edades de las poblaciones y describir su patron anual de migracion. Registramos 6100 a 8700 individuos/ano y determinamos la edad de aproximadamente el 60% de las aguilas que pasaron: 20% juveniles (902), 37% subadultos (1679) y 43% adultos (1910). Observamos el mayor volumen migratorio (67%) despues de las 1200 H, con un pico entre las 1400–1500 H. Para estos tres anos, la fecha mediana de paso de juveniles fue anterior a la fecha mediana de paso de los subadultos y adultos. La proporcion de diferentes clases de edad en 2012 fue significativamente diferente de la registrada en 2013 (G = 18.4, P < 0.001) y 2014 (G = 147.4, P < 0.001). No hubo...