History & Background - Population declines
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Tens of millions of vultures used to be present across India, Pakistan and Nepal. The vast numbers of vulture present were due to the very large numbers of livestock reared across South Asia. Government statistics indicate that livestock numbers in India have exceeded 400 million since the 1980s and reached more than 500 million in 2005. In India and Nepal cows have a sacred status for Hindus and are not consumed. As a consequence very large numbers of livestock carcasses became available for vultures in Asia and became the principal food source for the resident species of vultures. Vultures were so abundant that the Parsi religion in India and Buddhist communities on the Tibetan plateau utilised vultures for sky burials in order to cleanly and efficiently dispose of human bodies.
The vulture declines in India were first quantified at Keoladeo National Park, Rajasthan, by Dr. Vibhu Prakash, Principal Scientist of the Bombay Natural History Society. Between 1985-1986 and 1996-1997 the population size of Oriental white-backed vultures declined by an estimated 97% at Keoladeo, and in 2003 this colony was extinct. These declines were coupled with high mortality of all age classes. Following the initial survey, in 2000 BNHS teams undertook over 11,000 km of road based surveys, repeating 6,000 km of road-transects previously surveyed for raptors in the early 1990s, and confirmed that declines of >92% had occurred in all regions across northern India (Prakash et al. 2003). Some birds appeared sick and lethargic for a protracted period before death. Across South Asia tens of millions of vultures have now died.
Road transect surveys covering more than 5000 km of road and track have been undertaken across India to survey numbers of vultures. The first survey in 1991-93 was set up to monitor raptor populations and was undertaken by researchers including Dr Vibhu Prakash. Vultures were also counted during this survey. The surveys covered central and northern India (the "cow belt" where most vultures formerly occurred) and visited 18 national parks and protected areas on the survey route (see map on the right). Repeat surveys by the BNHS, covering the same route and methodology, were undertaken in 2000, 2001, 2003 and 2007 in order to monitor trends in vulture numbers.
The latest survey in 2007 indicates that numbers of Oriental white-backed vultures have declined by a staggering 99.9% over the preceding 15 years (see Prakash et al 2007). Long-billed and slender-billed vultures have decreased by 97% over the same period. For more details on this survey and the published paper follow this link. Surveys across Nepal and Pakistan indicate vultures have declined at similar rates across the whole of south Asia, and within Pakistan both resident species (white-backed and long-billed) are on the edge of extinction.
The rates of population decline are staggering, with white-backed vultures in India declining at an average rate of 48% a year for the period from 2001 to 2007. Long-billed and slender-billed vultures are estimated to be declining at around 22% a year. Numbers of white-backed, long-billed and slender-billed vultures in India were estimated to number around 11,000, 45,000 and 1000 birds, respectively in 2007. Vulture numbers have continued to shrink at the same rate since these estimates were made in 2007.
Populations of red-headed vultures and Egyptian vultures are declining at 41% and 35% a year in India and are listed as Endangered and Critically Endangered (see Cuthbert et al 2006)
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