Assam has released 10 captive-bred vultures — five critically endangered slender-billed vultures and five white-rumped vultures — into the wild at the Jatayu Aviary in Biswanath Wildlife Division, part of Kaziranga National Park & Tiger Reserve, marking what conservationists say is the first-ever release of captive-bred slender-billed vultures fitted with GSM-GPS satellite transmitters anywhere in the world.
Background
India's vulture populations collapsed catastrophically between the early 1990s and mid-2000s, with the oriental white-backed vulture falling to just 0.1% of its early-1990s numbers by 2007, and the long-billed and slender-billed vulture populations combined dropping to roughly 3.2% of their earlier levels — an overall loss of more than 95% of India's vultures within about 15 years, among the fastest population collapses ever recorded in a bird species. The Bombay Natural History Society (BNHS) first documented the sharp decline in 1999, and subsequent research identified the cause: diclofenac, a veterinary anti-inflammatory drug widely used to treat cattle, proved lethal to vultures that fed on the carcasses of treated animals, causing fatal kidney failure. India banned diclofenac for veterinary use in 2006, followed by bans on similarly toxic drugs including ketoprofen, aceclofenac and nimesulide in subsequent years, but by then vulture numbers had already fallen so low that natural recovery alone was judged insufficient without active captive breeding and reintroduction.
Vultures were, prior to this collapse, among the most abundant large birds of prey across the Indian subcontinent, with white-backed vultures in particular once so numerous around cattle carcass dumps and slaughterhouses that ornithologists described their disappearance within roughly a decade as among the fastest population crashes ever documented in any bird species anywhere in the world, faster even than the collapse of the passenger pigeon in North America a century earlier when measured as a percentage decline over time. The scale and speed of the crash caught conservationists off guard specifically because it was not driven by habitat loss or hunting, the more typical causes of large bird declines, but by a single veterinary drug whose lethal effect on vultures went undetected for years because the birds' deaths from kidney failure after feeding on treated carcasses were not immediately connected to the drug's veterinary use in cattle.
Key Details
- Vultures released: 10 total — five slender-billed vultures (Gyps tenuirostris) and five white-rumped vultures (Gyps bengalensis), both classified as critically endangered.
- Release location: Jatayu Aviary at Tewaripal, Biswanath Wildlife Division, within Kaziranga National Park & Tiger Reserve.
- Breeding source: The Vulture Conservation Breeding Centre (VCBC) at Rani, Kamrup district, one of four Jatayu Conservation Breeding Centres established in India by BNHS and state forest departments with support from the Royal Society for the Protection of Birds.
- Tracking technology: Each released bird carries a GSM-GPS satellite transmitter and colour identification rings, enabling researchers to monitor movement, survival and adaptation to wild conditions.
- World-first claim: This is reported as the first-ever release of captive-bred slender-billed vultures anywhere in the world fitted with GSM-GPS satellite tracking for post-release monitoring.
- Acclimatisation process: The birds were moved from the Rani breeding centre to the Biswanath release aviary roughly three months before release to acclimatise to natural conditions ahead of their soft release on 8 August 2026.
- Led by: Assam Environment, Forest & Climate Change Minister Jayanta Mallabaruah, who conducted the release.
The choice to fit GSM-GPS transmitters specifically to the slender-billed vultures in this release, rather than relying solely on the coloured leg rings used in earlier reintroduction efforts at other centres, reflects a broader shift across global conservation practice toward real-time satellite tracking as breeding programmes mature and the questions being asked shift from simply whether captive-bred birds can survive release at all, toward more detailed questions about their ranging behaviour, feeding site selection, interaction with wild-born vultures, and long-term breeding success once released. Leg rings alone can confirm a bird has been sighted alive at a given point, but cannot capture the kind of continuous movement data satellite tracking provides, which is particularly valuable for a species like the slender-billed vulture whose remaining wild populations are sparse enough that chance visual resightings are rare.
At a Glance: India's Vulture Crisis and Recovery Effort
| Milestone | Detail |
|---|---|
| Population collapse period | Early 1990s to mid-2000s |
| Overall population loss | More than 95% |
| Oriental white-backed vulture, 2007 | 0.1% of early-1990s population |
| Long-billed + slender-billed combined, 2007 | 3.2% of earlier population |
| Cause identified | Diclofenac (veterinary NSAID), documented by BNHS in 1999 |
| Diclofenac veterinary ban | 2006 (India) |
| First successful captive breeding at Rani (both species) | 2012 |
| This release | 10 birds, 8 August 2026, world-first GPS-tagged slender-billed release |
Why Rani and Assam Matter to This Story
The Vulture Conservation Breeding Centre at Rani, near Guwahati in Kamrup district, is one of just four Jatayu Conservation Breeding Centres established across India in response to the diclofenac crisis, alongside sister centres at Pinjore in Haryana, Rajabhatkhawa in West Bengal, and Bhopal in Madhya Pradesh. Rani holds particular significance within this network because 2012 marked the first year the centre achieved successful captive breeding of both the white-backed and slender-billed vulture, a milestone that took years of careful work to reach given how slowly vultures reproduce compared with many other bird species — they typically lay only a single egg per breeding attempt and do not reach breeding maturity for several years, meaning building a genetically healthy captive population large enough to support periodic wild releases has been a multi-decade undertaking rather than a rapid turnaround effort.
Assam's specific role as host to both the Rani breeding centre and the Biswanath release site places the state at the centre of India's vulture recovery effort in a way that goes beyond simply hosting one part of the programme. Kaziranga National Park & Tiger Reserve's broader ecosystem, with its mix of grassland, riverine forest and large populations of grazing herbivores including the park's famous one-horned rhinos, wild buffalo and various deer species, provides exactly the kind of carcass availability and open habitat that vultures need to successfully forage and establish territories after release, making the choice of Biswanath Wildlife Division a deliberate one rather than an arbitrary release location.
Local Impact
For Assam's ecosystem, vultures play an outsized ecological role disproportionate to their numbers: as obligate scavengers, they clear animal carcasses rapidly and efficiently, limiting the spread of disease that can occur when carcasses are left to decompose over longer periods or are scavenged instead by feral dogs and other less efficient scavengers, which themselves can become vectors for disease transmission to humans and livestock. The near-total collapse of India's vulture population in the 1990s and 2000s has been linked by researchers to downstream public health consequences, including increases in feral dog populations around carcass dump sites and associated rabies transmission risk, making vulture recovery a public health as well as a conservation concern for the communities living around Kaziranga and Biswanath.
For Assam's broader wildlife tourism and conservation reputation, hosting the world's first GPS-tagged release of captive-bred slender-billed vultures adds to the state's existing profile built around Kaziranga's one-horned rhino conservation success, positioning Assam's forest department and its partnership with BNHS as leaders in a highly technical and long-term conservation effort that few other states or countries have matched at this level of tracking sophistication.
For farmers and livestock owners in the areas surrounding Biswanath and the wider Kaziranga landscape, a recovering vulture population carries practical benefits distinct from its conservation value: efficient carcass disposal by vultures reduces the burden on farmers of managing dead livestock, a task that otherwise often falls to manual burial or open disposal, both of which carry their own labour costs, land use implications and disease risks if not managed carefully. A functioning vulture population effectively performs this disposal service for free, a form of ecosystem service that becomes newly visible in economic terms precisely because its near-total absence for several decades made the alternative costs of carcass management more apparent to rural communities across the region.
The involvement of BNHS, one of India's oldest and most respected wildlife research organisations, founded in 1883, lends this specific release additional scientific credibility beyond what a government release alone might carry. BNHS's role in first documenting the vulture population crash in 1999, and its subsequent decades-long partnership with state forest departments to establish and run the Jatayu Conservation Breeding Centres, means the organisation has tracked this crisis and its recovery effort from its earliest identification through to this latest technologically advanced release, giving it a rare institutional continuity across the full arc of the vulture conservation story in India.
Vultures Elsewhere in Northeast India and Beyond Assam's Borders
Assam's vulture recovery effort, coordinated through Kaziranga, Biswanath and the Rani breeding centre, sits within a wider Northeast Indian context where vulture populations, like elsewhere in South Asia, suffered similarly severe declines during the diclofenac crisis, though the region's comparatively lower cattle density and different livestock management practices in parts of the hill states meant the impact was not uniform across all of Northeast India. Assam's Brahmaputra Valley, with its larger cattle population and more extensive plains agriculture, historically supported some of the region's largest vulture colonies before the crash, making the state a logical priority location for reintroduction efforts once captive breeding populations reached a scale sufficient to support wild releases.
Community awareness has also played a role in the broader recovery strategy beyond the technical breeding and release programme itself: conservation groups working alongside BNHS and the forest department have run outreach efforts in villages near release sites to explain why diclofenac use in cattle remains banned and why alternative, vulture-safe anti-inflammatory drugs like meloxicam should be used instead, since continued illegal or accidental diclofenac use anywhere within a released bird's foraging range could undo years of captive breeding investment in a single exposure event. This community dimension is arguably as important to the programme's ultimate success as the breeding and tracking technology itself, since no amount of GPS monitoring can protect a released vulture from feeding on a contaminated carcass if the underlying drug-use risk in the surrounding landscape has not been addressed.
What Happens Next
The GSM-GPS transmitters fitted to each of the 10 released vultures will allow the Assam Forest Department and BNHS to monitor the birds' movement, survival rates and behavioural adaptation to wild conditions over the coming months and years, generating data that conservationists say will directly inform the design of future release programmes for both species. Given that this is described as the first release of its kind for GPS-tagged slender-billed vultures globally, the tracking data gathered from these specific 10 birds is likely to carry weight beyond Assam, potentially shaping vulture reintroduction strategy at the other Jatayu Conservation Breeding Centres in Haryana, West Bengal and Madhya Pradesh as well.
The release follows a broader pattern of conservation activity at Kaziranga this year, with Assam ministers also visiting the Centre for Wildlife Rehabilitation and Conservation (CWRC) at Borjuri near Kaziranga to review rescue and rehabilitation operations, and inaugurating new eco-tourism infrastructure including the Florican Eco-Tourism Gate at Naramari, suggesting sustained state government attention to both active species recovery programmes and the wider wildlife tourism and rehabilitation infrastructure surrounding the park.
The Centre for Wildlife Rehabilitation and Conservation at Borjuri, which the visiting ministers reviewed alongside this release, has itself rescued 10,096 wild animals across 303 species as of 31 July this year, of which 6,642 have been successfully rehabilitated and released back into the wild — figures that place the vulture release within a much larger, ongoing pattern of wildlife rescue and reintroduction activity centred on the Kaziranga landscape, rather than as an isolated event. That scale of rescue and rehabilitation activity, spanning hundreds of species, underscores the breadth of wildlife pressure in the region, much of it linked to the same flood-prone, human-wildlife-interface geography that also makes Kaziranga's floodplain ecosystem so ecologically productive in the first place.
Looking further ahead, the success or failure of this specific release will likely be measured less by any single dramatic outcome and more by the steady accumulation of tracking data over months and years: whether the released vultures survive their first months in the wild, whether they range within or beyond the Kaziranga landscape, whether they eventually breed successfully in the wild rather than only in captivity, and whether their presence measurably affects local carcass disposal patterns. Conservation programmes of this kind typically consider a release genuinely successful only once captive-bred birds have been confirmed breeding in the wild themselves, a milestone that, if reached, would represent the ultimate validation of the multi-decade effort that began with BNHS's first documentation of the crisis in 1999.
Frequently Asked Questions
How many vultures did Assam release and where?
Ten captive-bred vultures — five slender-billed and five white-rumped — were released at the Jatayu Aviary in Biswanath Wildlife Division, part of Kaziranga National Park & Tiger Reserve, on 8 August 2026.
Why is this release described as a world first?
It is reported as the first-ever release of captive-bred slender-billed vultures fitted with GSM-GPS satellite transmitters for post-release monitoring anywhere in the world.
Why did India's vulture population collapse so dramatically?
Diclofenac, a veterinary anti-inflammatory drug used to treat cattle, proved fatal to vultures feeding on treated carcasses, causing kidney failure. This caused a population loss of more than 95% between the early 1990s and mid-2000s before the drug was banned for veterinary use in 2006.
Where were the released vultures bred?
At the Vulture Conservation Breeding Centre (VCBC) in Rani, Kamrup district, one of four Jatayu Conservation Breeding Centres in India run by BNHS with state forest departments and support from the Royal Society for the Protection of Birds.
How will the released vultures be monitored?
Each bird carries a GSM-GPS satellite transmitter and colour identification rings, allowing researchers to track movement, survival and adaptation to wild conditions.
Why do vultures matter ecologically?
As obligate scavengers, vultures rapidly clear animal carcasses, limiting disease spread that can occur when carcasses decompose or are scavenged by less efficient animals like feral dogs, which themselves can become disease vectors.
Are slender-billed and white-rumped vultures still endangered?
Yes, both species remain classified as critically endangered despite the diclofenac ban and ongoing captive breeding and reintroduction efforts.
How many Jatayu Conservation Breeding Centres exist in India?
Four: at Pinjore (Haryana), Rajabhatkhawa (West Bengal), Rani (Assam) and Bhopal (Madhya Pradesh), run by BNHS and state forest departments with support from the Royal Society for the Protection of Birds.
When did the Rani centre first successfully breed vultures?
2012 marked the centre's first successful captive breeding of both the white-backed and slender-billed vulture, a milestone reached after years of careful management given vultures' slow reproductive rate.
What is the Centre for Wildlife Rehabilitation and Conservation at Borjuri?
A wildlife rescue and rehabilitation facility near Kaziranga that had rescued 10,096 wild animals across 303 species as of 31 July 2026, with 6,642 successfully rehabilitated and released back into the wild.
What drug replaced diclofenac for veterinary use?
Meloxicam, an alternative anti-inflammatory drug found to be safe for vultures, is the primary substitute promoted for veterinary use in cattle, alongside continued bans on other vulture-toxic drugs including ketoprofen, aceclofenac and nimesulide.
Can the public help with vulture conservation in Assam?
Community awareness efforts near release sites focus on ensuring farmers use vulture-safe drugs like meloxicam rather than diclofenac in treating cattle, since even a single contaminated carcass within a released vulture's foraging range can undo years of breeding investment.
For a species that once numbered in the tens of millions across the Indian subcontinent before collapsing to near-invisibility within little more than a decade, the release of just 10 birds at Biswanath is a small step measured against the scale of what was lost, but it represents the leading edge of a recovery methodology — captive breeding, careful acclimatisation, satellite tracking and community-level drug-use awareness — that conservationists increasingly view as the template other countries facing their own vulture crises, including parts of Africa now experiencing diclofenac-related declines of their own, may eventually need to follow.
Sources
This report draws on coverage by The Sentinel (Assam), ANI, Free Press Journal, New Kerala and Asianet Newsable, along with background research from the Bombay Natural History Society and peer-reviewed population decline studies on Gyps vultures in India and Nepal. Population decline figures reflect the most widely cited peer-reviewed surveys from the mid-2000s, and current population trend data is monitored on an ongoing basis by BNHS and the Jatayu Conservation Breeding Centre network.