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.
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
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.
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.
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.
AZA Institutions Hosting Vulture Events
Albuquerque Biological Park
Cameron Park Zoo
Cheyenne Mountain Zoo
Detroit Zoological Society
Disney’s Animal Kingdom
Elmwood Park Zoo
Living Desert Zoo and Gardens State Park
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
Virginia Aquarium & Marine Science Center
Woodland Park Zoo