The vulture is often depicted as death’s maligned servant, circling ominously in the clouds in search of decay. We’ve come to associate these creatures with disgust—but I don’t think the stigma is warranted.
It’s the spookiest time of the year, so as I did last year, I’d like to introduce you to one of nature’s spookiest animals. You probably think of vultures as exploitative, conniving creatures that feast on the demise of the innocent. But vultures serve a vital role in our ecosystems, and I don’t think the bad reputation is warranted.
Nature long ago realised the importance of cleaning up rotting, toxic corpses, driving two distantly related bird families to evolve similar traits, such as the characteristic bald heads. The New World vultures—including our familiar turkey vulture and the enormous condors—populate North and South America. The Old World vultures—more closely related to hawks and eagles—populate Europe, Africa, and Asia. People have long thought that the bald heads were so the birds could, in the words of Gizmodo’s Hudson Hongo, “really get in there,” but instead the trait is probably the result of multiple evolutionary stresses, most notably the need for good temperature control. The two families are the only vertebrates in the world that rely completely on scavenged carrion for sustenance, according to one paper.
Also, our New World vultures shit and piss all over their legs to keep cool. And when threatened, they vomit. Their extremely acidic stomach juice allows them to eat decaying flesh already smells bad enough to keep predators away. Pretty neat if you ask me.
Humans once revered both vulture families. The patron goddess of upper Egypt, Nekhbet, was a represented as a white vulture. Condors—the largest land birds in the western hemisphere—have taken on sacred roles in American traditions. Sky burials, essentially a burial-by-vulture, still occur in Tibet and elsewhere. Vultures and the humans of early civilisation relied on one another; the vultures got free meals, while cleaning up dead livestock and people and their associated smells and toxins.
By eating carcasses, vultures shorten the amount of time we’ve had to spend beside rotting flesh, even today. That role is more than convenient. Recent research has found that New World turkey and black vultures have incredibly low levels of bacterial diversity in their stomachs, 76 kinds versus 562 kinds on their faces. Common vulture gut bacteria include clostridia and fusobacteria—microbes that are harmful to other animals, which the vulture has presumably removed from the environment through their carrion consumption. Our vultures have evolved to survive these bacteria’s toxic effects, and might even benefit from their presence because the bacteria help break down carrion.
But our positive associations with vultures likely came to an end during industrialisation. Humans now clean up carcasses ourselves, leaving little for vultures. Those carcasses that are left are tainted with veterinary drugs like the anti-inflammatory diclofenac. Then there’s the bioaccumulation of agricultural chemicals that wind up moving up the food chain. Both types of chemicals happen to be harmful to the vultures. Hunters leave lead shot in animals, furthering up the risks of vultures ending up with a poisoned meal. And roadkill scavengers can end up becoming roadkill themselves.
Of the world’s 23 vulture species, 14 are endangered, including the charismatic California condor which went extinct in the wild in 1987 due to lead poisoning and poaching (its numbers have since rebounded somewhat thanks to conservation efforts). Our changing behaviours have so constricted vulture’s food sources that in Europe, griffon vultures have begun doing the previously unthinkable—killing prey for food.
It’s time to rethink our relationship with vultures. One study of the Egyptian vulture found that they cleaned up nearly a quarter of one Yemeni town’s organic waste. Scientists have suggested that we need to rethink what we do with our waste—and think carefully, since simply leaving extra carcasses for the vultures doesn’t seem to work, either. Vulture research has led to some positive political action; farmers are now allowed to leave carcasses in certain places for vultures to clean up, and South Asian countries have banned diclofenac.
If you’ve worried you’ve offended vultures with the term’s modern-day connotations, there are plenty of other birds whose behaviour is more unsavoury that could serve as better shorthand for humans doing bad things. Skuas and jaegers are big, fat seabirds that chase and harass smaller gulls and terns until their victims puke up their catch. Cowbirds and cuckoos will lay their eggs in smaller birds’ nests, forcing the smaller bird to care for the nestling at the expense of its own children. Cassowaries literally kill humans.
S0, vultures, thank you for your services. I’m sorry that we humans have messed things up for you and your image.