美国国家公共电台 NPR Biologists With Drones And Peanut Butter Pellets Are On A Mission To Help Ferrets（在线收听）

LULU GARCIA-NAVARRO, HOST:

In central Montana, drones are dropping peanut butter pellets on prairie dog colonies. As Yellowstone Public Radio's Nate Hegyi explains, it's part of an effort by biologists to save North America's most endangered mammal.

(SOUNDBITE OF PRAIRIE DOGS HOWLING)

NATE HEGYI, BYLINE: Under a half-crescent moon, U.S. Fish and Wildlife Services biologist Randy Matchett sweeps a spotlight back and forth over a cold, black prairie. Suddenly, a pair of brilliant, green eyes pops out of the darkness.

RANDY MATCHETT: No.

HEGYI: Look at those eyes.

MATCHETT: Don't those eyes look amazing?

HEGYI: They belong to a black-footed ferret, the most endangered mammal in North America.

KRISTY BLY: They're these ferocious, masked bandits of the prairie. They're like these little slinkies.

HEGYI: That's Kristy Bly, a senior biologist with the World Wildlife Fund. She says there's only about 300 black-footed ferrets left in the wild. And they depend almost entirely on prairie dogs to survive.

BLY: Prairie dogs are Chicken McNuggets of the prairie, where so many species eat them.

HEGYI: But in recent years, prairie-dog towns across the American West have been exposed to a deadly disease called sylvatic plague. While it's treatable in humans, sylvatic plague can wipe out entire prairie-dog towns in less than a month. And that means no more food for endangered black-footed ferrets. So Kristy Bly, Randy Matchett and a team of scientists and engineers have spent this year vaccinating prairie-dog towns in central Montana against the plague using drones.

BLY: Run, run, run, Forrest, run.

HEGYI: The sun is up now. And a drone named Shep is zooming over a prairie-dog town. Every 30 feet or so, it shoots out these little blueberry-sized pellets. They taste like peanut butter. Prairie dogs love peanut butter. But they're laced with a live vaccine that protects these little guys from the plague.

BLY: We have to keep enough alive in enough places to keep ferrets alive.

HEGYI: Bly says if they can stop the plague from killing prairie dogs, the endangered ferrets population could grow. And using drones like Shep helps that happen faster. In the past, scientists delivered the vaccine baits by hand. Drones cover a lot more ground. But this is only the second year anyone's used one to save ferrets. So there's still a couple of kinks, like when Shep suddenly veers off its pre-mapped path and begins to head home.

KURT KREIGER: It's - I think it's jammed.

HEGYI: Kurt Kreiger, the drone's pilot and engineer, coaxes Shep to the ground. The team huddles around it, pulling pieces apart and inspecting the pellet shooter.

KREIGER: I'm frazzled a little bit. But, you know, you have clearer minds going, hey, why don't you just check this? Oh, yeah...

HEGYI: And once they fix the drone, the team refills it with peanut butter pellets...

(SOUNDBITE OF POURING PELLETS)

HEGYI: ...Turns it on.

(SOUNDBITE OF BEEPING)

HEGYI: ...And then the drone takes off.

(SOUNDBITE OF DRONE FYLING)

KREIGER: There it is. Shep's on his way. Do we have pellets dropping? Something just - yep. There they go. Something just shot off the side. Boom. Boom. Look at them go.

HEGYI: By the end of the day, they hope to expose more than 4,000 prairie dogs to the vaccine. In the past, field trials showed prairie dogs living in vaccinated areas survived waves of the plague. And when the prairie dog can beat the plague, Bly says it's good for everything, including the ferret.

BLY: Without it, do you really have a complete ecosystem? You start taking those pieces apart. And it's like a domino effect. When we have ferrets on the landscape, the piece of the puzzle that is the American prairie all fits together.

HEGYI: For NPR News, I'm Nate Hegyi in Montana.

(SOUNDBITE OF LYMBYC SYSTYM'S "SCIENTIFIC ROMANCE")