Unintended Consequences: Asian Vulture Populations Brought to the Brink of Extinction

Vultures.  If you had asked me ten years ago what I thought about vultures, I would have told you “not very much.”  I’d see turkey vultures (Cathartes auara) soaring through the Maryland sky– but beyond that, I didn’t give them a second thought.

Cape griffon vulture in Namibia. Copyright Tim Lewthwaite.

Then, at an AZA Conference in Chicago, I met Maria Diekmann, founder of the Rare and Endangered Species Trust (REST) in Namibia.  This native Californian moved to southern Africa in the early 1990s and founded REST – an organization dedicated to saving the Namibian population of the Cape griffon vulture (Gyps coprotheres). The Cape griffon population in Namibia suffered a dramatic decline over the last fifty years.  The causes for the decline are complex and numerous – and REST is working to address these. But this blog post isn’t about the good work that REST is doing in Namibia – or the role REST has played in opening my own eyes to the beauty – and fragility – of these majestic raptors.

This post is about a larger tragedy that has swept over vulture populations in Asia, bringing them to the brink of extinction in a matter of years. The culprit you ask? The tragic declines have been caused by the introduction of a veterinary product meant to help in the treatment of livestock.

Asian Vultures in Crisis

Mature Oriental white-backed vulture at a Bombay Natural History Society breeding center. Copyright Chris Bowden, Royal Society for the Protection of Birds.

By the late 1990s, catastrophic declines were occurring in several species of vulture in India. Surveys confirmed population losses approaching 50 percent each year – a staggering figure by any standard.  The species most affected belong to the genus Gyps: Oriental white-backed vulture (Gyps bengalensis), long-billed vulture (Gyps indicus) and slender-billed vulture (Gyps tenuirostris). In the 1980s, the Oriental white-backed vulture was thought to be the most common large bird of prey in the world with a population in the tens of millions. Between 1992 and 2007 its population crashed by 99.9 percent, bringing it to the brink of extinction.

In 2003, The Peregrine Fund identified poisoning by the non-steroidal anti-inflammatory drug (NSAID) diclofenac as the cause of these population crashes. Diclofenac, one of the cheapest and most widely used NSAIDs since its patent lapsed, has proved to be highly toxic to Gyps vultures. After death, the carcasses of cattle, including those that have been treated with the drug, are left to be consumed by vultures. Traces of the drug in the carcesses cause kidney failure in the vultures when consumed. The birds become sick and die within a few days. Several alternative NSAIDs have also been found to be toxic to Gyps vultures. So far, the only veterinary NSAID known to be ‘vulture safe’ is meloxicam, and although the price is coming down, this is still more expensive than diclofenac.

White backed vultures feeding at vulture Safe Zone in Nepal. Copyright Richard Cuthbert, Royal Society for the Protection of Birds.

Once the cause of decline in vulture numbers was identified, Bombay Natural History Society (India) with financial and technical support from Royal Society for the Protection of Birds (United Kingdom), set about its conservation work, which includes high-level advocacy programs about the use of veterinary diclofenac, setting up of captive breeding centers to establish a source of birds for reintroduction into the wild in future, monitoring levels of diclofenac in cattle carcasses and identifying alternatives to reduce exposure of wild vultures to diclofenac-contaminated food. As part of the ongoing efforts to conserve Asia’s vultures, the Save Asia’s Vultures from Extinction Consortium (SAVE) has been established.

What has this got to do with AZA-accredited institutions you ask?  September 3, 2011 is International Vulture Awareness Day and a number of institutions are participating with their own events.   The events will provide a great opportunity to see these wonderful raptors up close and learn about the threats they face in Asia – and increasingly, in other parts of the world – and what is being done to save them while also helping farmers maintain the health of their livestock.

A young Ruppell's griffon vulture (Gyps ruppellii) at the Phoenix Zoo. The Phoenix Zoo is studying its vultures and will provide information on raising vultures for release into the wild to organizations fighting to save vulture species. With the Ruppell's vulture, this will help with reintroduction efforts in the Sahel region of Africa. Copyright Paige McNickle, The Phoenix Zoo.

Now, when I see the turkey vultures overhead – fortunately still a fairly common sight in Maryland – I take a moment to appreciate their beauty and I am grateful they are thriving.

Tim Lewthwaite

AZA Institutions Hosting Vulture Events  

Albuquerque Biological Park

Brookgreen Gardens

Cameron Park Zoo

Cheyenne Mountain Zoo

Detroit Zoological Society

Disney’s Animal Kingdom

Elmwood Park Zoo

Living Desert Zoo and Gardens State Park

Naples Zoo

National Aviary

Palm Beach Zoo

Reid Park Zoo

Riverbanks Zoo and Garden

Saint Louis Zoo

San Diego Zoo Safari Park

Seneca Park Zoo

Six Flags Discovery Kingdom

St. Augustine Alligator Farm Zoological Park

The Phoenix Zoo

Tracy Aviary

Virginia Aquarium & Marine Science Center

Woodland Park Zoo

Zoo Atlanta

White backed vulture landing at REST's vulture restaurant in Namibia. Copyright Tim Lewthwaite.

This entry was posted in Animal Health, Animal Management, Aquarium, Conservation, Education, Research, Vultures, Wildlife, Zoo and tagged , , , , , . Bookmark the permalink.

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