Scavengers in dire straights

[Donna]

For most people, the slow spiral of airborne vultures means that some unlucky animal has died. Now, in some regions of the world, vulture populations are dying. An American scientist is part of an international effort to save these massive scavengers. Ann Murray has the story:

It’s hard to get too excited about an ugly bird that eats dead, rotting flesh. Let’s face it, vultures don’t have a good rep. But vultures are amazing animals. They can eat 20% of their own body weight in one sitting. And they have digestive systems with special acids that will dissolve toxic bacteria and viruses. Meaning, vultures prevent the spread of killer diseases like rabies and anthrax when they scarf down the carcasses of sick animals.

“With the meat goes the disease.�

That’s Todd Katzner, Director of Conservation and Field Research at the National Aviary in Pittsburgh. Katzner says, sadly, with all the good vultures do, many species are in big trouble.

“Vultures are in dire conservation straits in much of the world because of things like habitat loss, poisoning and now these new problems like diclofenac.�

Diclofenac is a medicine given to sick livestock in central Asia. Vultures that eat livestock carcasses with traces of the drug almost always die of immediate kidney failure. It took scientists some time to figure that out. Katzner’s friend Vibhu Prakash, an Indian ornithologist, recognized the beginnings of this vulture die-off.

“This was almost 20 years ago that Vibhu started seeing vultures near Barrackpore, India. They were sitting in a tree with their heads hanging down .Eventually they’d just fall out of the tree and die on the ground.�

Since then, Indian white-backed vulture numbers have plummeted from 30 or 40 million birds to just thousands. This massive decline has left scientists scratching their heads about how many vultures are left in central and south Asia and other parts of the world. Because vultures move around a lot, it’s been hard to keep track of individuals. There’s never been an accurate total population count - anywhere. That’s where Katzner and the National Aviary come in.

For several years, Katzner and his field team have been traveling to mountainous grazing lands in Kazakhstan and the northern plains in Cambodia . Katzner says the one place vultures reliably congregate is at feeding sites.

“We ask people if any livestock have died .We drive up to those sites . Usually the vultures have been there. When vultures feed on the carcass they leave feathers everywhere. And when we go to the carcass, we’re able to pick up sometimes 500 or 1000 feathers.�

Once the feathers are collected, Katzner’s team extracts DNA from them to identify individual birds. The scientists will use this information to create population models. This new counting method is faster and more reliable than capturing, marking and recapturing birds.

Katzner expects researchers will use his feather- based system to count endangered vultures in other places. That includes here, in the United States, where California Condors are dying from lead poisoning.


Before I leave the Aviary, Katzner points out an American black vulture. She’s gobbling a breakfast of chick pieces and mice. Katzner hopes his work will help to keep other vultures happy and hungry. He says we all need ‘em on the job as nature’s cleanup crew.