There are eight species of vultures flying the skies over Africa: bearded, Egyptian, hooded, white-backed, white-headed, lappet-faced, Cape and Rüppell's. At least, there used to be.

Together, the eight species of African vultures have declined by an average of 60 percent. Seven of them – all but the bearded vultures – have declined by more than 80 percent. The worst off are the white-headed and Rüppell's vultures, which have declined by 96 and 97 percent, respectively.

Vulture Infographic 2015 06 22
Together, the eight species of African vultures have declined by an average of 60 percent. Seven of them have declined by more than 80 percent. (Click to enlarge.)

And here's the most depressing part. The main causes for the birds' decline, together responsible for 90 percent of reported vulture deaths, are entirely preventable: poisoning and traditional medicine.

As scavengers and carrion eaters, vultures are ecologically important. Their main function, at least as far as humans are concerned, is to keep the number of mammal scavengers at any given carcass down. That, in turn, limits the spread of diseases and pathogens among Africa's mammals, and reduces the likelihood of humans coming into contact with those nasty bugs.

When the vultures of Asia began to decline in the late 1990s, feral dogs suddenly had easy, predictable access to carcasses – and their populations exploded. As a result, feral dogs became the primary reservoirs for rabies. The "Asian vulture crisis" saw India spend an additional $34 billion US dollars on healthcare between 1993 and 2006, all thanks to the loss of these key scavengers.

Could Africa be headed down a similar path? Various reports of vulture declines throughout Africa have appeared since at least the year 2000, but this week a group of researchers who comprise the IUCN Vulture Specialist Group have published the first comprehensive report of the conservation status of all eight African vultures for the entire continent in the journal Conservation Letters. 

These long-lived birds must do quite a bit of developing before they're ready to reproduce, and when they do, they successfully fledge just one chick every year or two. For species such as this (ecologists call them "K-selected"), it doesn't take many deaths to severely impact a population.

The researchers, led by Darcy Ogada of The Peregrine Fund and the National Museums of Kenya, amassed data covering nearly 60% of Africa's surface area and 95 national vulture populations from within 22 nations. Of those, 85 populations are either nationally extinct or are in serious trouble. (Tanzania can boast a dubious record: of those species historically present there, only half were in decline.) Although declines were worst in unprotected landscapes, vultures are in trouble even in protected areas like national parks and game reserves.

More than 60 percent of vulture deaths – at least for those deaths with known causes – can be attributed to poisoning (much like the American relatives, the California condors). Poisoning is often unintentional: the birds die after eating carcasses that have been baited with poisons as a means of controlling animals like hyenas and jackals, or in some cases feral dogs.

However, vulture poisoning is not always an unintended side effect. Some poachers have begun to intentionally poison carcasses as a means of killing off vultures, since the birds' overhead circling can alert wildlife authorities to the location of a poached animal. It is therefore possible that as the rhino and elephant poaching crises have accelerated in recent years, so too has intentional vulture poisoning. Since July 2011 alone, ten poisoning incidents in six African countries have been responsible for the deaths of at least 1,500 vultures.

An additional 30 percent of vulture deaths result from trafficking in vulture parts, which are thought to cure various physical illnesses and psychological ailments in some African cultures. They're also sometimes used as charms for good luck, success or even increased intelligence. In addition, smoked vulture meat is trafficked internationally, much of it coming from West Africa.

"Our findings suggest that, together, poisoning and the illegal trade in vulture body parts for medicines or as bushmeat pose a substantial threat, and on a continental scale," write the researchers.

“The main causes for the birds' decline, together responsible for 90 percent of reported vulture deaths, are entirely preventable.”

In some ways, the situation is not as serious as the Asian crisis was – at least not yet. The declines are happening more slowly even among the worst-affected African species. And that means there might still be time to reverse the trend. Governments can start with legal changes to regulate the use of poisoned carcasses. Not only would this help them sidestep some serious ecological and economic consequences if the continent's scavengers were to disappear, but it would also eliminate the need for pricey captive breeding and reintroduction programmes down the line. 

And there are other measures that could make a difference, too. Ten percent of vulture deaths are due to electrical infrastructure. All over Africa, vultures are routinely electrocuted when they fly into power lines, or carved into smithereens when they fly into wind turbines. There are ways to generate electricity – even so-called "green energy" – in a way that is friendlier for birds, both in terms of construction and placement.

Nearly twenty years after the world learned of the Asian vulture crisis, it is perhaps time to announce that Africa is experiencing a vulture crisis of its own. Six of its eight species have declined enough that Ogada and her colleagues recommend considering them as critically endangered. "Governments must act now," they say, "to avoid the environmental and social consequences of losing what are arguably nature's most important scavengers."