Why falling vulture population can cause health crisis

Vultures feeding on a carcass at the Maasai Mara Game Reserve. PHOTO | GEORGE SAYAGIE | NATION MEDIA GROUP

What you need to know:

  • The African vulture’s population has declined by up to 98 per cent.
  • Vultures clean up the environment just as garbage collectors do. 
  • In the Maasai Mara the birds have reduced by 50 per cent in the last 30 years.

In Samburu and Laikipia counties, cattle enclosures are made of strong metallic bars and chain links to keep predators away.  

In the far flung villages in the north, herders hastily guide their cattle into the predator-proof enclosures before nightfall to keep their livestock from predators that have turned their homes into hunting grounds.   

But also inadvertently benefiting from the corrals are large birds whose carrion-eating lifestyle has led them to death-traps.


Known for their distinctively balding heads, dull plumage, and beady eyes, vultures are some of the most unattractive creatures in the wild that feed on    decomposing carcasses.  

Across the country and in many parts of the world, vultures are dying in large numbers. Their deaths are linked to man and his acrimonious activities.

The African vulture is now threatened with extinction. Its population has declined by up to 98 per cent.  

In the Maasai Mara, for instance, the birds have declined by 50 per cent in the last 30 years.

Recently, a farmer in Rumuruti, Laikipia County, was arrested for allegedly poisoning and killing 11 rufous vultures, seven tawny eagles, and a silver jackal – all endangered species.


If found guilty, he could pay a Sh5 million fine or be imprisoned for five years or both.

Kenya Wildlife Service (KWS) officials suspect that after the farmer’s two camels that went missing for four days were killed by a lion, he poisoned the carcasses, resulting in the inadvertent death of the 19 carrion hunters.

Such cases of brazen human-wildlife conflicts are common.

But the ugly tricks at play to keep wild animals at bay, the losses farmers incur due wildlife attacks and the ultimate price both farmers and the wildlife pay at the end are costly. 

Unknown to many, vultures clean up the environment just as garbage collectors do.

Scientists warn that without the birds, human beings risk contracting zoonotic diseases such as rabies, Middle East Respiratory Sydrome Coronavirus (MERS-COV), anthrax and a host of other diseases that are transferable to humans by animals.

Zoonotic diseases or zoonoses [diseases which can be transmitted to humans from animals], according to scientists, currently represent the biggest proportion of emerging diseases such as Covid-19 which is believed to have originated from bats and pangolins.


Dr Beckie Garbett, Vulture Conservation Manager at Birdlife International, says that in absence of vultures, populations of other less desirable scavenging species such as rats and feral dogs could rise, which could have negative impacts on human health.

The avian scavengers, Dr Garbett says, are nature’s very own clean-up crew that keep landscapes free of rotting carcasses and in the process limit transmission of diseases.  

By consuming animal carcasses that would otherwise be left to rot and spread diseases, vultures keep the number of mammal scavengers down and prevent the spread of life-threatening diseases, she says.

Between 1992 and 2006 for instance, at least 47,300 people died of the rabies epidemic in India due to an increased population of feral dogs which subsequently resulted in increased dog attacks –38.5 million additional dog bites – and rabies outbreak.


A study counting the cost of vulture decline — an appraisal of the human health and other benefits of vultures in India published in 2008 found out that the rabies outbreak had a correlation to dramatic deaths of vultures in the country.

Unlike many birds of beauty whose roles are mainly plant pollination, vultures are well adapted to eating carcasses and are aptly equipped with a digestive system which contains special acids to dissolve any deadly pathogens.

The speed with which vultures clean up animal carcasses prevents the spread of diseases. Without them, more anthrax spores are expected to infect the soil and remain viable there for decades.

“It is our duty to ensure that vultures continue to grace our skies and help keep healthy ecosystems intact,” said Dr Garbett.

Globally, about one billion cases of illnesses and millions of deaths occur every year from zoonoses according to World Health Organization (WHO) estimates. The global health body also estimates that some 60 per cent of emerging infectious diseases that are zoonoses.

Over 30 new human pathogens have been detected in the last three decades, 75 per cent of which have originated in animals, WHO says.


Dr Darcy Ogada, a senior scientist at the Peregrine Fund, a non-profit organisation dedicated to protecting birds of prey, says that out of the eight known vulture species, four types are critically endangered globally, two are moderately threatened, while the rest are in safe zones.

She says that the threats are generally related to land degradation since many communities have encroached into wildlife conservation areas, thus predators find it easy to attack their homesteads and kill livestock.

The invasion sometimes never ends well for cattle owners. The Ministry of Tourism and Wildlife estimates that between 2014 and 2018, about 477 people were killed in human-wildlife conflicts while 1,263 survived with serious injuries.

Farmers whose animals are killed use poisoned baits to kill predators unaware of the accidental avian casualties.

While most vultures die as a result of poisoning, not all are killed by pastoralists. Others are executed by poachers who lace dead elephants and rhinos with poison to kill vultures that might tip off park rangers to their illicit activities.

Apparently, as charismatic animals such as elephants, pangolins, and rhinos are butchered for their worth, vultures paradoxically get punished for the supposed lack of it.


The glamorous species luckily have dozens of conservationists at their beck and call.

“A single poisoning can end up killing vultures in large numbers because they move in swarms,” Dr Ogada explained.

According to a researcher at Kenya Bird Map, Sydney Shema, raptors are important in ensuring parks are free from smells of rotting animal carcasses which could be a turn off to tourists.

"In game parks such as Maasai Mara where dozens of wildebeests die and drown in the river during their famous annual migration, the carcasses are usually never an issue because they are taken care of by the vultures," the ornithologist explained.

Between 2012 and 2014, more than 2,000 vultures were killed in poaching-related incidents in seven African countries according to Birdlife International.

There is an urgent need to create awareness among local communities on the dangers of using poisons to kill wildlife.


“Wildlife poisoning is the primary cause of Africa’s declining vulture populations. We must not be mistaken that poisoning is only dangerous to wildlife, it endangers human health and our natural environment. It must stop,” added Dr Garbett.

Some researchers in Laikipia and Samburu counties are already training local pastoralists on proper handling of chemicals and how to identify poisoned animals.

So far 800 farmers have been trained on chemical safety and livestock management while at the same time they are encouraged to install predator-proof enclosures.

About 350 predator-proof cattle enclosures have been constructed over the last 18 months in the regions.

“Many farmers have no idea how poisonous some of these chemicals are. They use them without wearing protective gear hence they end up affecting their health,” said Dr Ogada.

He added that the chemicals can also contaminate water sources.


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