Picture a vulture and you’ll most likely have a hard time separating these gawky creatures with the social stigmas they hold, long being reviled as portents of death. Still, these ungainly birds play a crucial role in maintaining our ecosystems and well-being, so citizens should be as concerned as scientists are to know that vultures in some parts of the world are quickly disappearing, according to a recent University of Utah study.
Many vulture species are now declining or even close to extinction due to concentrated toxins in the carrion they eat. Such toxins often have widespread impacts on a vulture population, as dozens if not hundreds of vultures tend to swarm and feast on a single carcass. Once vultures grow scarce, they leave the field open for other scavengers to flourish, species that bring with them the potential to carry dangerous bacteria and viruses from carcasses into heavily populated cities.
88% of threatened vulture species are impacted by the presence of poisons within carrion. In North America, only 22 California condors remained by 1982, due to their consumption of toxic lead bullet fragments left in the bodies of hunted animals However, intense conservation efforts have since helped the species grow to over 400 who inhabit California, Arizona, Utah and Baja California, Mexico.Similarly, more than 95% of India’s vultures had disappeared by the early 2000s, which was traced to diclofenac, a drug that relieved pain in cattle, but proved deadly to vultures who flocked to cattle carcasses; fortunately, this drug was banned through international coordination efforts, and the birds have slowly increased.
Now, the vulture crisis is centered in sub-Saharan Africa, where pest-control poisons are so potent that they have been affecting birds, mammals and insects alike on a massive scale. For instance, in 2007 an elephant carcass poisoned in Namibia killed around 600 vultures. These vultures in Africa are also the direct victims of poachers who poison carcasses specifically to silence the birds who might give away the location of illegally killed animals.
Declining vulture populations will have negative consequences for human health as they make way for foragers like dogs, rats, and crows, all of whom have more frequent contact with humans than relatively-solitary vultures. Vultures are highly efficient carrion consumers, often finding and eating carcasses within an hour after death, before decay really sets in; plus, vultures’ stomachs are highly acidic, thus killing most bacteria or viruses present in carrion. In these ways, vultures help prevent diseases from dead animals spreading to human populations. However, other scavengers without these features could easily pass along those diseases to humans, as many are entrenched in cities. Following the decline of vultures, India feral dog count increased by around seven million and was linked to a rabies outbreak that killed 48,000 people from 1992-2006.
Vulture populations can be restored through careful and collaborative efforts by the international community, as evidenced by the story of California condor. However, it is important that these efforts start now if we want to retain a creature which, though vilified for its appearance and its eating habits, plays a vital role in regulating the spread of bacteria and viruses and in maintaining healthy ecosystems and human populations, whether or not we are aware of how beneficial these scavengers are.
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