Scavengers in Dire Straights

  • Vultures 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. (Photo courtesy of the National Park Service)

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:

Transcript

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.

(sound of a vulture eating)

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.

For The Environment Report, I’m Ann Murray

Related Links

Birders Flock to Hawk Mountain

Each fall, thousands of hawks, eagles, and other birds of prey fly hundreds of miles in search of warmer climates. And between August and December, nearly 70-thousand people will climb to the top of a bird sanctuary called Hawk Mountain to get a closer look at those birds. The Great Lakes Radio Consortium’s Brad Linder reports:

Transcript

Each fall, about thousands of hawks, eagles, and other birds of prey fly hundreds of miles
in search of warmer climates. And between August and December, nearly 70-thousand
people will climb to the top of a bird sanctuary called Hawk Mountain to get a closer
look at those birds. The Great Lakes Radio Consortium’s Brad Linder reports:


“Those of you haven’t found the osprey, it’s over there at owl’s head, naked eye here to
the right.”


On a clear day, the view from atop Hawk Mountain stretches for more than fifty miles.
But on this particularly hazy Saturday afternoon, bird-watchers are pushing their
binoculars and telescopes to the limits.


“Well, we’re making them out there, they’re coming in. It’s like you just gotta wait ’til
they get a little closer than what they typically do. They’ve been popping out of clouds
and haze all day for us.”


Doug Wood is a volunteer at Hawk Mountain in Eastern Pennsylvania. This afternoon,
he’s the official bird counter.


“We’re basically taking a lot of field information. Wind, weather, temperature, cloud
cover, wind direction. And then we’re basically monitoring the birds’ species, age, sex,
and recording it every hour.


“Look! An Osprey! And then fade to scene change.”


Researchers at Hawk Mountain have been keeping records of osprey and other migratory
raptors for more than seventy years, making it the oldest monitoring station in the world.


In the early twentieth century, hunters would shoot thousands of birds from the
mountainside each year. Today, people travel from all over the world to shoot birds with
their cameras.


Matt Wong came all the way from New Zealand to study at the sanctuary.


“Hawk Mountain is internationally renowned as a hawk watch site. And also a place
where big research actually happens. Now, not many of the locals around Pennsylvania
actually realize this, but it’s actually huge on the international scene. It’s world
recognized, and that’s one of the reasons why I came here.”


In Wong’s country, there are only two species of raptors. In America, he’s had a chance
to study dozens of varieties.


But even with so many different species populating North America, many people still
think of them as strangers or sometimes even as monsters.


“I still get, amazingly to me, a lot of people that think that these birds are out to get us.”


Volunteer Bob Owens has spent the last 20 years doing education programs at Hawk
Mountain.


“If you intrude into their territory when they have young in the nest, or something like
that, yeah, they’re probably going to chase you. As far as them killing babies and taking
them from baby carriages, this is all old wives tales. This just does not happen.”


Owens runs a small farm for a living, where he says hawks and barn owls help keep
rodents under control. But in a larger sense, Owens says there’s a lot people can learn
from these birds.


“Any three and a half pound bird that can apply four hundred pounds of pressure with its
talons is built to do what they’re doing. They are at the top of the food chain. And that’s
the other big thing that it shows us. It just opens up a door here as to all the reasons the
birds are either dropping or rising in population. What are we doing?”


Owens says in the seventy years researchers at Hawk Mountain have been counting birds,
they’ve seen populations rise and fall. Hawks and eagles are hardy birds. But even the
most successful predators can fall victim to environmental change.


Keith Bildstein is the sanctuary’s director of conservation programs. He says raptors are
like sensitive tools, telling researchers when something’s wrong with an ecosystem.


“Birds of prey are excellent biological indicators. In the middle of the last century they
told us that we were having a problem with our misuse of organochlorine pesticides,
specifically DDT. Today, they’re leading us in explorations of the spread of West Nile
Virus.”


Bildstein says because raptors are at the top of the food chain, when their numbers fall
it’s a pretty good sign that their food source is dwindling, their habitat could be
disappearing, or air quality might be suffering.


But for most of Hawk Mountain’s visitors, the birds are more than barometers of a
healthy ecosystem. According to birder Judy Higgs, they’re beautiful creatures,
especially when viewed from a great height.


“These birds are just majestic. And the other thing is that they go so far. You know,
some of these birds are going to South America!”


Higgs first climbed the mountain in 1970, when she was a student at nearby Kutztown
University. Before moving out of state, Higgs used to come to Hawk Mountain daily…
she stills visits on weekends whenever she can.


“I used to do work in the morning, come here in the afternoon, go home, and finish my
work at night so I could be here.”


By day’s end, Higgs and her fellow birdwatchers count more than 600 raptors. During
the fall season, as many as 70-thousand predatory birds, from vultures to falcons might
pass by on their way to distant points.


For the Great Lakes Radio Consortium, I’m Brad Linder.