Halting Brown Snakes Of Guam

The brown tree snake of Guam is a slithering, voracious invader: a frightening nuisance for those in its path. But what the snake has done to Guam's wildlife is the real ecological horror story. As 48 Hours Correspondent Peter Van Sant reports, this nocturnal nightmare will consume almost anything.

Dr. Gad Perry knows that stopping this Micronesian munching machine is extraordinarily hard. There may be up to 2 million of the serpents on Guam, possibly the highest density of brown tree snakes on earth.

"They will eat lizards," he says. "They will also eat mammals. They'll eat birds. They'll eat eggs. They'll eat garbage."

Dr. Perry notes, "This thing can eat a thing that's 60 percent of its body weight in one big gulp. It's like [you're] eating your neighbor's rottweiler. I mean, it's good at what it does. It's really, really good."

You can actually hear what the brown tree snake has done to the jungles of Guam. Once its skies echoed with the sounds of singing birds.

Dr. Gad Perry

"When it happens right at home, and you see in your lifetime populations of birds just disappearing and knowing that they may be gone forever and never coming back, it's almost impossible for me to put it into words," says Dr. Kelly Brock, protector of the last of what is considered to be Guam's national bird, the Guam rail.

After only existing in captivity, the rail has again been released into the wild. But no one knows if it will survive there. Smithsonian pathologist Don Nichols says the chances look pretty grim. Nearly 8,000 miles away, he is plotting germ warfare against the brown tree snake.

"What I'm trying to do is find some kind of disease that we can release onto the island that is specific for snakes," says Nichols. "There [are] two particular strains of virus I'm looking at right now, which, in the laboratory, cause severe disease and death in these snakes."

Nichols is in a race against time. Tourists may never know there are serpents in this paradise. But when the sun goes down, the snakes come out and it's a full-time job to stop them. Danny Rodriguez and his crew from the U.S. Department of Agriculture are on the front lines.

"They're very aggressive; they're really not afraid of anything either," says Rodriguez. "The largest we caught is a nine-footer."

Each night, the unit captures snakes at Anderson AiForce Base, the commercial airport and the island's ports to prevent the brown tree snake from finding its way onto cargo leaving Guam.

"And they're very sneaky, and they can penetrate through just about anything," Rodriguez continues. "They stow away into these compartments of the aircraft. They'll find the smallest hole and fit themselves in thereÂ…and you can catch as many as you can, but they still come back."

A snake-sniffing dog goes to work.

Over the last four years, there have been three snake sightings verified in Hawaii. Lester Kaichi and his dog Gypsy are the last line of defense. They check every flight that lands from Guam to make sure the brown tree snake never gains a belly hold.

"Any plane that arrives from Guam or any piece of cargo has a potential to harbor a brown tree snake," says Kaichi. "And you walk in there with one dog and see all the potential hiding places that a snake could beÂ….You're just overwhelmed."

"One snake alone could change everything. I can't imagine Hawaii having no birds. It's a battle we hope we don't lose," he says.