At the wrong end of the food chain | Global Ideas | DW | 15.09.2015
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Global Ideas

At the wrong end of the food chain

Vultures are highly specialized birds, essential for the health of the environment. But their population has decreased dramatically. The birds are being poisoned, Borja Heredia told DW, often intentionally.

Photo: Capture of Andean Condor in Ecuador (Source: Ruth Muñiz)

Borja Heredia works with the Convention on Migratory Species to protect endangered birds

Global Ideas: Globally speaking, how big is the problem of poisoning?

Borja Heredia: Bird poisoning is a global issue. It happens in all continents and regions in the world, and it affects a variety of species of different groups - including water birds, songbirds, birds of prey. The fact that predators are on the top of the food chain makes them more vulnerable to poisoning, because the poison accumulates along the food chain. Birds of prey have been very much affected, mainly in Asia but also in Europe and in Africa.

Why are birds of prey so vulnerable?

The problem is complicated, it has several issues. Sometimes birds of prey are intentionally targeted with poison. In some regions where hunting of small game like rabbits is very popular, the hunters use poison intentionally to kill birds of prey, since they might kill the game species. It is very well known in areas like Scotland, where the hunting of grouse is popular - birds of prey are targeted and deliberately poisoned.

Photo: Dead vulture. Source: Andre Botha

Victims of superstition: Those who eat vultures are believed to gain the ability to see into the future

The hunting of birds, especially vultures in South Africa has a background in traditional medicine. What do people associate with those birds?

It's a particular problem in Africa - South Africa and also West Africa. Because vultures can find their food even in vast areas of savanna, people think that they can predict the future. And this is very strong belief. It makes people think that if you eat parts of a vulture, you will win the lottery or find a nice wife or husband. This is very much embedded in some of the local cultures, and there is a tradition to use vulture parts as "medicine."

Birds have been hunted for a very long time, why is this now affecting the species?

The situation can be called a vulture crisis. It started in Asia for different reasons than in Africa. In Asia a veterinary product caused a sharp decline of vultures. This medicine works very well for the cattle, but it's lethal for the vultures. When they fed on the dead carcasses of the livestock, they absorbed the medicine which caused kidney failure and the death of the vultures. Now, this product has been banned and the species are recovering.

A new vulture crisis has emerged in Africa. The decline is also very steep. The problem here is intentional poisoning for traditional medicine in the first place, but secondary poisoning is also a reason.

Describe the crisis in Africa, is it possible to name certain figures of vulture loss?

We know that in around the last 10 years there has been an 80 percent decline of a combined number of vulture species. This is of course a very strong signal that things are going wrong. We know that Africa has a situation with wildlife crime in general, which means the poaching of elephants, rhinos and other species for the illegal trade of these species. Here, vultures come into the picture as side victims. They are considered as a sentinel species, which means they tend to circle above a carcass if they find one. That's something poachers don't like, because the vultures are indicating where the carcass is and thus where the poachers are. So the poachers are intentionally poisoning these carcasses to kill the vultures.

Photo: Vulture. Source: Juergen Schneider

Vultures are important for the ecosystem as they 'clean nature' by eating dead animals

What impact does the killing of these birds have on the ecosystem as a whole?

Vultures in general provide a very important ecosystem service: they clean nature. Different vultures have specialized in different eating habits. Some are only after carcasses of bigger animals to go for the meat, others only feed on the guts and soft parts of the same carcasses. Finally, the lammergeier, as the most specialized vulture, feeds only on the bones of the dead animals.

In the end, the whole carcass is gone because different vulture species have consumed different parts of it. This process is also preventing mammals like foxes or hyena from spreading a number of diseases.

With this in mind, what would a world without vultures look like?

Well, a very important part of the ecosystem would be missing. I can make that more clear on another example from the vulture crisis in Asia. In India and Pakistan, health workers witnessed an increase in rabies that was directly linked to the loss of vultures. Because they were not around anymore to get rid of the carcasses, feral dogs did the job. But these dogs are carriers of diseases.

We were talking about the poison, the pesticide that kills the vultures. Where is this chemical used and where does it start its effect?

The chemical is used to control pests in agriculture. It is a very strong pesticide that is now banned in Europe, Canada and the US. But the problem is that there are still amounts of the pesticide available that are used in other parts of the world, for both agricultural purposes and to poison wildlife. It can be acquired relatively easily, and it can be used in different forms to poison mammals like lions, hyena, leopards, wild dogs, or birds of prey or vultures.

Photo: Vultures feeding. Source: RSPB Images

Vultures often fall victim to deliberate or accidental poisoning

Many African countries lack the infrastructure to effectively protect their bird populations and enforce the law. How can this be improved?

Most African countries have already passed legislation that is prohibiting or controlling the poisoning. But there's of course a difference between having laws on paper, and laws that are really implemented. This is a challenge we face in Africa at the moment. Capacity-building will be the key, and we really have to cooperate with the countries and transfer the know-how and good practices that have been developed elsewhere.

Borja Heredia is the leading bird expert at the #link:http://www.cms.int/:Convention on Migratory Species# (CMS). The biologist holds a PhD in ecology from the University of Madrid - during the 1980s he worked in the Spanish Environment Ministry. His focus is on conservation of endangered species.

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