Vultures: A Symbol of Death

I know I am two days late in posting for International Vulture Awareness Day (IVAD09), but I didn’t want to not post altogether.  Maybe I’m a bit of a freak, but I love vultures.  I mean it…I really LOVE them!

One of the advantages to living in the South was that I saw them all the time.  Turkey vultures are one of the only birds I can identify in flight.  But it’s the black vultures that I really came to love the most.  While Christie and I worked at our research site at Cockroach Bay Aquatic Preserve in Hillsborough County, Florida, we would sometimes get visitors.  We would get egrets, herons, and gators,but none I looked forward to as much as the black vultures.  On the days we worked late into the golden hour just before sunset, they would swoop in one by one and perch in the tree above our little patch of mangroves.

Credit: Allie Wilkinson

Credit: Allie Wilkinson

I’m not alone in my love and respect for vultures. More than 100 organizations participated in IVAD this year, in countries all across the world.  The organizations span as many continents as vultures, which are found  on every continent except Oceania and Antarctica.  If you want to know more fun facts, check out the EcoWorldy article, “16 cool facts about vultures“.

So at the point you may be wondering, why all this fuss about vultures?  Even Charles Darwin disliked them at first.  Most people find vultures ugly, evil, and associate them with death.  Well, if you thought the last one, then you are pretty close.  Although vultures have historically been regarded as a symbol of death, they are the ones dying these days, particularly the Old World vultures.

Vultures have been persecuted by humans over the last hundred or so years.  They have been shot, trapped, and poisoned.  Kenya holds the record for one of the largest numbers of vulture deaths in a single incident.  In 2004, in Athi-Kapiti plains, adjacent to Nairobi National Park, 187 vultures died after eating an animal laced with the lethal pesticide Furadan.  Vultures are the hardest hit birds in East Africa, but that is nothing compared to their losses on the Indian subcontinent, where tens of millions of vultures have been lost over the last decade.

As recently as the 1980s, there were 40 million vultures in India.  Today there are just 60,000.  ”The decline of Asian vultures is one of the steepest declines experienced in any bird species,” says Dr. Debbie Pain, Head of International Research for the Royal Society for the Protection of Birds.  The Indian white-rumped vulture (Gyps bengalensis) has been the hardest hit with a 99.9 percent population decline; once so abundant that they were probably the most common large bird of prey in the world, now only ONE survives for every THOUSAND that lived in 1992.  The Long-billed vulture (Gyps indicus) and Slender-billed vulture (Gyps tenuirostris) have also declined 97 percent.

Although several causes were suspected for the decline, research published in 2004 in the scientific journal Nature confirmed that the vultures were dying from veterinary use of the non-steroidal anti-inflammatory drug (NSAID) Diclofenac.  The three year study was conducted by The Peregrine Fund and the Ornithological Society of Pakistan.

Credit: The Peregrine Fund

The study found that 85 percent of the 259 vultures studied died of visceral gout, a condition caused by renal failure.  The vultures that died of other causes than visceral gout tested negative for diclofenac residue.  When the vultures eat carcasses of livestock that have been given diclofenac, they are poisoned from bioaccumulation of the chemical.  Diclofenac is fatal to vultures at ten percent the recommended dose for mammals.

At the 2005 meeting of the National Wildlife Board, the Indian government announced a phaseout of diclofenac.  Unfortunately, farmers are still using diclofenac, in the human form, to treat their livestock.  Even small-scale usage can have catastrophic effects.  As few as 760 carcasses obtaining diclofenac at a dose lethal to vultures would be sufficient to cause the observed decline in vulture numbers, which is 30 percent a year.

Vultures are vital to the ecosystems in which they live.  As scavengers, they help with sanitation, thereby reducing the risk of disease such as anthrax, TB, and foot-and-mouth disease.  They also help control pests like rats and feral dogs, through competition for food.  These other scavengers are not nearly as efficient as vultures, and leave behind rotting corpses that the farmers and government then have to deal with.  Dr. Hazell Shokellu Thompson, Birdlife‘s Regional Director for Africa, said, “Vultures provide a perfect example of the link between birds and people.  Loss of vultures would mean loss of important natural services to people, for example the cleaning of the environment of animal carcasses and waste at no charge.”

The decline in vultures has also lead to an increase in feral dogs in many places, which in turn has led to a rise in rabies with almost 50,000 human casualties.  The rabies problem is so widespread that India has launched a plan to sterilize over eight million dogs in the next ten years.  The shift in transfer of corpse pathogens from vultures to feral dogs and rats can lead to a disease pandemic in a country as crowded as India.

Vultures are indicators for ecosystem health, much like the “canary in a coal mine”.  An ecosystem without them is an unhealthy one, and an incomplete one.  If we don’t learn to love vultures, then we will lose them, and we will be the ones to suffer.  If we don’t step in to help their public relations and give them an image makeover, or fund captive breeding projects, then they really will become a symbol of death.  They are already declining faster than the dodo.  Let’s not allow them to become extinct too.