AUDIE CORNISH, HOST:
We're going to experience next the release of 900 endangered toads. This happened on the arid plains of Southeast Wyoming, the only place in the world where the Wyoming toad exists. The release is an attempt to bring back one of the most endangered amphibians in North America. Wyoming Public Radio's Melodie Edwards takes us there.
MELODIE EDWARDS, BYLINE: Next to a small pond, U.S. Fish and Wildlife Service technician Elizabeth Mack passes out latex gloves and instructions.
ELIZABETH MACK: You know, all you have to do is open up the tub and very gently take the toad and set it on the ground.
UNIDENTIFIED WOMAN: Don't step on them.
MACK: And don't step on them.
EDWARDS: Clear, plastic tubs are stacked shoulder high. Inside, brown speckled toads climb the walls trying to escape. And escape is exactly what a crowd of ranchers, conservationists and biologists are hoping for. Mack opens one of the tubs. Five-year-old Lettie Newman peers in.
LETTIE NEWMAN: Oh, they're so excited. I've never seen a toad hop so crazy before.
EDWARDS: Crazy because they were bred in captivity, and this is their first encounter with their natural habitat. The Wyoming toad only exists in this basin, but about 40 years ago, it nearly disappeared. The hope today is to bring them back. With gloved hands, everyone begins scooping toads and placing them gently in the mud.
UNIDENTIFIED MAN: Yep. We'll just let one go, and we won't walk that direction. Yep, put them down.
EDWARDS: Among the crowd are a few old toaders, people who've been studying this little critter for decades. University of Wyoming zoology professor Bill Gern says it was his friend the late, great herpetologist George Baxter who first took him out in search of the Wyoming toad.
BILL GERN: So in the spring of 1980, George and I started going to his favorite haunts to try to find toads, and we couldn't. And he became very puzzled at that time. He said, well, they used to be everywhere, and we couldn't find them anywhere.
EDWARDS: Gern says the toad used to be so common ranchers found them in their cowboy boots. But after searching for years, the two men decided the toad was extinct. Then a fisherman found a few in a lake. Fish and Wildlife rounded up every one they could find and put them all in captivity. Gern and others started trying to figure out what was killing them.
GERN: They found that these toads were dying of a fungus infection, and that was big news.
EDWARDS: The chytrid fungus, to be exact, an infection killing amphibians worldwide. But Fish and Aquatic Conservation Director Greg Gerlich says modern irrigation has also hurt their numbers. He says these toads are very sensitive.
GREG GERLICH: Pesticides have an easy transport through amphibian skin. The skin's very permeable.
EDWARDS: Pesticides like those used in agriculture or to kill mosquitoes. Across the highway, rancher Fred Lindsay released 300 toads on his land. He uses old-fashioned flood irrigation that spreads out shallow water among willows - perfect for Wyoming toads.
FRED LINDSAY: We have at times kept some of the irrigation water flowing longer than we normally would. And it pushes haying back just a little bit, but that's OK. That's OK.
EDWARDS: Lindsay says the Wyoming toad's ideal habitat is also ideal for ranching, which means to bring them back, they'll have to thrive on private land. He says he knows a lot of ranchers worry that when you have an endangered species on your property, the feds will butt in on your business. He hasn't had that problem.
LINDSAY: We signed what's called a safe harbor agreement. And basically what that means is during normal operations, if we were to run over a toad or step on a toad, we wouldn't go to federal prison.
EDWARDS: After today, Lindsay looks forward to hearing the sound of Wyoming toads breeding on his land.
(SOUNDBITE OF TOADS CROAKING)
EDWARDS: And with every single one of those 900 toads embedded with a tracking chip, Fish and Wildlife will be able to keep a very close eye on just how many do survive. For NPR News, I'm Melodie Edwards in Laramie. Transcript provided by NPR, Copyright NPR.