Martin Gilbert
Did You Know?
- Traditional Parsi and Tibetan sky burials directly involve vultures. In these rituals, the bodies are not buried. Rather, they are placed in an open area, where vultures consume them.
- Once considered among the most abundant of the large birds of prey in the world, populations of Slender-billed Vultures on the Indian subcontinent dropped dramatically to less than 1% of their population in as few as 10 years.
- According to scientists the decline of the Slender-billed, Oriental White-backed and Long-billed Vultures populations represents some of the "most rapid sustained declines in the total population size of a bird species ever documented."
- The Slender-billed Vulture and the Indian Vulture were once considered to be just one species, known as the Long-billed Vulture. Today, they are recognized as separate species.
How The Peregrine Fund is Helping
In 2003, The Peregrine Fund discovered that the veterinary drug Diclofenac was responsible for a catastrophic collapse of vulture populations in South Asia in less than a decade. The drug was banned for veterinary use in 2006 by India, Pakistan and Nepal, and Bangladesh took similar action in 2010.
The Peregrine Fund was the first conservation organization to set up “vulture restaurants” in South Asia. "Vulture restaurants" are where biologists set out carcasses that had never been treated with Diclofenac so, they are safe for vultures to eat.
We are also working to support local students, and are working with communities to educate them about the importance of vultures, as we continue to monitor the populations to help us understand if populations are stable, rising or going down, and many other exciting things.
The Peregrine Fund also helps support vultures worldwide by promoting and celebrating International Vulture Awareness Day, which is the first Saturday in September each year! You can help by celebrating this day on your own by going out and watching vultures in your area, or by encouraging others in your family, school or neighborhood to celebrate too!
Watch Peregrine Fund biologist - Munir Virani - as he gives a Ted Talk on Why I Love Vultures!
Where They live
The Slender-billed Vulture is found throughout much of Asia, including such beautiful countries as India, Nepal, Bangladesh, Cambodia, Laos, and Burma. In the past, it was also considered a regular visitor to the Malay Peninsula. Sadly, however, that was a long time ago. There haven't been any records of the species on the Peninsula for more than 50 years.
This lovely vulture uses savannas, arid open country mixed with some wooded patches, generally in lower elevations, to forage, feed, roost and nest. Though it tends to avoid humans and human-inhabited areas, the draw of an easy meal can sometimes lure it in. The species might be observed searching for a tasty meal while dumpster diving in trash bins or garbage dumps or patrolling the grounds of a local slaughterhouse!
What They Do
The Slender-billed Vulture is a stunning, if not a bit disheveled looking, creature. In fact, some have not been opposed to using the word "scruffy" to describe its appearance. It has a long black neck and a black head, both of which are almost completely featherless. It has piercing, dark eyes and, of course - a long, shiny, slender bill. Its back and breast are covered in a mix of darker brown, light brown and beige feathers. Its legs are partially covered with cream-colored feathers, which are visible in flight, making it easy to pick out this vulture from some of the other species found within the same landscape.
Unlike many other raptor species, vultures do not exhibit outwardly visible traits of sexual dimorphism. This means that the male and female look identical to each other in size and plumage color/patterns.
New World vultures (such as the Turkey Vulture or the Black Vulture) don't have voice boxes - so they are limited to just hissing and grunting for vocal communication. Old Word vultures (those that live in Asia, Europe and Africa), on the other hand, do have voice boxes and though their vocalizations aren't much more melodic, they do have a larger repertoire of sounds which includes squeals, shrieks, and croaks.
As nature's clean-up crew, vultures and other carrion eaters often consume organisms in dead and decaying animals that are harmful to humans and the environment. In fact, around a hundred of these birds can strip a 100-pound carcass in three minutes, thereby helping to contain any spread of disease. They truly help keep us safe and the environment clean! Vultures like to be clean, too. In fact, it is important for all birds to keep their feathers neat and well-groomed. But you’ve never seen a bird with a hair brush, right? Instead, they use their beaks to clean, or preen, their feathers.
Like all vultures, Slender-backed Vultures have very few feathers on their heads. When they eat, they often need to put their heads deep into the cavities of rotting carcasses. If particles of this meat got deep into their feathers, they might cause bacteria or germs to grow. Though some people might think vultures look ugly, the fact is a bald head helps keep vultures healthy – and the more healthy vultures we have around the better.
But there is another reason that vultures have only fine, small feathers on their heads. Their bald heads might also help them to stay warm or keep cool, depending on the weather. When they are cold, they can tuck their necks in, closer to their bodies, to keep them warm and cozy. When it is hot outside, vultures can extend their necks soaking up the sun's rays through the skin on their necks and heads. When it really wants to get out of the heat, taking off into flight also helps - as the cold air rushes past its (mostly) bare skin patches.
Why They Need our Help
This once common vulture is now on the verge of extinction. Throughout much of its range, populations have dropped by more than 97% in only the past 15 years! This is due to the effects of Diclofenac, a drug that farmers and veterinarians give to aging livestock to help alleviate their suffering. But, when these livestock dies, the Diclofenac remains in their systems so when the vultures come down to feast on the carcass, they consume meat and tissue that contains this drug. Sadly, it is lethal to vultures, meaning the vultures will die.. Even a trace of diclofenac in a carcass is enough to cause vultures to die slowly and painfully. Just one cow carcass can poison hundreds of vultures
Sadly, this drug is still used to treat livestock in some areas although a safer alternative is now available. Scientists have seen evidence that vulture populations may be stabilizing, but, tragically, some species already have declined by up to 99 percent, making extinction a continued threat to these ecologically and culturally important birds.
To make matters worse, the effect of the vulture population decline on people is becoming evident, too. The drop has caused an increasing population of feral dogs, rats, and other animals more likely to come into contact with humans and spread rabies and other diseases. Keeping all this in mind, it is very clear how important it is to conserve this important species.
What They Eat
The Slender-billed Vulture, like most other vultures, is principally a carrion eater. But you might want to think twice about accepting a dinner invitation from a vulture. Carrion isn't the bag you take with you on the airplane when you travel. Carrion is the dead and decaying flesh of animals that are already dead! The Slender-billed Vulture is not picky about which animals it will eat; it only has two requirements: it needs to be relatively large and and it needs to be dead! This vulture will feed on dead cattle, deer, or just about anything else it can find.
Usually, several species of vultures, including the Slender-billed Vulture, will gather at a single carcass. Some individuals will spar, or fight, with each other to maintain the best position at the carcass. Slender-billed Vultures aren't super aggressive and seem to tolerate quite well the presence of other species - taking a bit more of a relaxed attitude toward its competitors.
Though they can eat, and likely prefer freshly-dead meat, they can eat much older carcasses without a problem.
Humans, of course, would get extremely sick, if we tried to eat meat that was even slightly rotten. Old meat can harbor bacteria that would surely give us food poisoning or maybe even anthrax! But Vultures are able to eat old, rotting,stinking, festering meat without ever falling ill. If that weren't gross enough, many vulture species access the meat, not by tearing into the tough hides (or skins) of the dead animals, but rather by entering through the softer parts of an animal's body, most often through the anus! That means that vultures aren't only eating old meat, but they are probably ingesting at least some feces as an appetizer - if you will!
So, how are they able to eat all of these things, and remain healthy? Vultures not only tolerate this diet, but are in fact, adapted to eat this way. First, they have very acidic stomachs, which helps to kill off any harmful bacteria. Scientists also believe they have developed immunity to certain bacteria, so they are unaffected by it.
Let's face it - we owe a big thanks to vultures for doing the very dirty job of cleaning up rotting carcasses and ridding our landscapes of certain diseases and, let's face it, some pretty disgusting smells.
Nest, Eggs, and Young
Unlike many similar vulture species, the Slender-billed Vulture is not a cliff nester. Instead it nests mostly in tall trees that dot the plains where it lives. It also doesn't nest in large groups, or colonies.
The Slender-billed Vulture builds a sturdy nest made up of sticks and twigs. Once the nestling hatches, it will grow quickly and therefore, requires a lot of food to help it grow healthy and strong.
Unlike an eagle or a falcon, which rip off small pieces of fresh meat which they carefully feed to their nestlings, vultures have a very different way of feeding their young. A nestling vulture's diet is composed entirely of regurgitated food until it is old enough to feed itself. Now you might be wondering how this all works. Well, the adults will eat what they can and then fly back to their nests. Once there, they will actually throw up - or regurgitate - the semi-digested food into their nestlings’ mouths, which the young birds happily and greedily eat. Though it might seem gross to us, it is actually a very efficient and safe way for vultures to bring food to their young. Remember, they don't possess the strong legs and talons of other raptors, so it would be quite a difficult task for them to carry a cow's leg or other body part back to the nest!
There still a lot to be learned about the nesting behavior and ecology of the Slender-billed Vulture.
Slender-billed Vulture and The World Center for Birds of Prey
The World Center for Birds of Prey offers fun ways to learn about raptors. Interactive activities, tours, interesting videos and a children's room with activities from coloring sheets and quizzes to costumes and a touch table are all available for the curious mind. We also have several different birds of prey on display year-round, including California Condors and a Turkey Vulture. Come for a visit to see vultures up close and learn more about these fascinating birds! Our knowledgeable staff and volunteers are on hand to answer any questions you may have about Slender-billed Vultures or other birds of prey.
References:
del Hoyo, J., N. Collar, and J. S. Marks (2020). Slender-billed Vulture (Gyps tenuirostris), version 1.0. In Birds of the World (J. del Hoyo, A. Elliott, J. Sargatal, D. A. Christie, and E. de Juana, Editors). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.slbvul1.01
Global Raptor Information Network. 2021. Species account: Slender-billed Vulture Gyps tenuirostris. Downloaded from http://www.globalraptors.org on 25 Aug. 2021
