By Steve Zack
An appreciation of vultures is in the eye of the beholder. William Clark of the Lewis and Clark Expedition certainly appreciated them; Charles Darwin certainly did not.
Clark carefully described in his journal of 1806 the “butifull buzzard of the Columbia” that we now know as the California Condor. Darwin, in 1832, recounted his experience with “these disgusting birds” (in this case, Turkey Vultures) whose bare heads “revel in putridity.”
Beyond their beauty or putridity, however, our awareness must include the awful plight of vultures worldwide, due largely to the toxic world of poisons we foist upon them.
The sixth annual International Vulture Awareness Day, which we celebrate September 6, gives us an opportunity focus precisely on that issue.
Our mixed feelings about these birds are due to their unique life history. They are the only obligate scavengers (eating solely dead flesh) among birds and their bare heads allow for aggressive consumption of large carcasses of both wildlife and domestic livestock worldwide. It’s a visceral scene. Carcasses are consumed quickly and the vultures’ highly acidic stomachs help kill pathogens like rabies in decaying meat.
They are all large-bodied birds with broad wings that support extensive use of thermals in search of carcasses; they often fly very long distances searching. They are highly social birds, with scores of individuals of several species often seen together at large carcasses.
These two traits, moving long distances to find carcasses and responding in great numbers at them, amplify the population effects of such poisoning.
The poisoning problem is most acute for Old World vultures. In the 1990s, vultures of several species showed dramatic declines in the Indian subcontinent. These were later determined to be due to the use of veterinary drug diclofenac on domestic cattle and its subsequent consumption by vultures feeding on their carcasses. The drug, which causes renal failure in vultures, led to population declines as high as 99 percent.
Inexplicably, Spain is now pressing for use of veterinary diclofenac in Europe, placing vultures and other birds of prey there at risk.
Vultures in Southeast Asia have long been in decline as large, native wildlife has likewise been in decline – a trend that the rise of poisoning seems likely to speed up. A recent poisoning in Cambodia killed 13 vultures, heightening concerns about the remaining population and its vulnerability in a region numbering fewer than 200 vultures.
In the past 15 years, intentional poisoning of carcasses in Africa has driven down vulture populations as dramatically as was recently true in Asia. The causes of poisoning in Africa are manifold. Carcasses of livestock killed by lions are laced with poison to kill the returning predators – placing vultures feeding on those same carcasses in harm’s way.
At the same time, the growing slaughter of elephants for their ivory increasingly involves poisoning elephant carcasses to keep swarms of vultures from circling overhead and giving the poachers’ location away. Finally, when local people poison dry season water holes to kill wildlife for human consumption, vultures feeding on those carcasses die as well.
Overall, 12 of the 16 Old World vulture species have become endangered recently, first in Asia, now in Africa. The “Ecosystem Service” vultures provide in consuming large animal carcasses quickly is widely at risk. Absent vultures, carcasses are left to opportunistic scavengers that are less efficient and less specialized for the task, including feral dogs. This risks the spread of diseases like rabies and other pathogens, threatening both wildlife and human communities.
New World vultures and condors have been less threatened by poisoning, yet recovery efforts for the California Condor continue to be hampered by their ingestion of lead shot used in hunting game species. The iconic Andean Condor of South America is in decline, in part due to lead poisoning and due to the consumption of carcasses poisoned through the familiar conflict between carnivores and livestock we’ve seen in Asia and Africa.
Non-governmental organizations like the Wildlife Conservation Society work with communities to eliminate the use of poisoning and reduce carnivore-livestock conflicts. But we all need help in stemming the world of poisons. Veterinary drugs like meloxicam – non-toxic to vultures – now exist. Alternatives to lead shot likewise exist that can eliminate the contamination with lead of our meat and our water supply.
The major poisons used in Africa are carbofurans, highly toxic insecticides largely banned in the U.S., Canada, and Europe that threaten not only vultures but other wildlife and people, too.
The disappearance of vultures casts a grim light on the poisonous world we are creating and its effects on all living things. This day of awareness represents a gentle nudge for all of us to appreciate these birds that protect us and other wildlife from deadly pathogens.
Practitioners of witchcraft in Africa appreciate vultures, which they believe use clairvoyance to determine the location of food. Unfortunately, that appreciation sometimes leads to their killing vultures – the better to eat their brains and acquire their superior intuition.
I, too, long to see a wider appreciation of vultures and condors, but let’s please admire the bare heads and fantastically evolved stomachs of these “butifull buzzards” and spare their brains to enable them to continue performing a critical centuries-old ecological function in landscapes the world over.
Steve Zack is Coordinator of Bird Conservation for the Wildlife Conservation Society.