JEFFREY BROWN: For those stations not taking a pledge break, we have a report about an invasive fungus that's killing millions of bats across the country.
Tonight's story comes from Ed Jahn of "Oregon Field Guide," a production of Oregon Public Broadcasting.
ED JAHN, "Oregon Field Guide": A single bat can devour 600 mosquitoes, moths and other pests in a single hour. So despite their creepy reputation, scientists say it's life without bats that should terrify us. And it's why Pat Ormsby shudders at the news that entire bat colonies are now being wiped out.
PAT ORMSBEE: We're talking about the very real possibility of extinction of one or more species in a very short time.
ED JAHN: Pat says a wave of death has now killed over one million bats along the East Coast, and it's now headed for the Northwest. The killer is a mysterious disease that made its first appearance here in Howe Caverns, N.Y.
MAN: The water is moving down and forming the calcite.
ED JAHN: It was in this cave back in 2006 that two scientists, Paul Rubin and Ben Gunther, came upon rooms filled with dead bats. They suspected vandals, but it soon became clear that the problem was far bigger than that.
PAT ORMSBEE: Other reports started coming in of weird bat behavior, bats out in winter. There were a large number of dead bats that were being turned in in Albany County, N.Y. And when they started going around and looking, then they were going whoa, something's not right in the bat world, but we don't really know what this is.
ED JAHN: Scientists investigated and found that many of the bats were covered with unusual white blotches. They'd found the killer, and they called it White Nose Syndrome.
PAT ORMSBEE: There's a lot we don't know about White Nose. This has come on so quickly. But currently, the popular thinking is that White Nose Syndrome is caused by a fungus called Geomyces destructans. This is a cold-loving fungus that basically invades bats.
ED JAHN: The fungus is deadly because it strikes bats where they live -- in cold, dark caves where bats winter together, sometimes in colonies of thousands.
PAT ORMSBEE: And we think it causes them to arouse during wintertime. And they basically burn up their fat reserves and starve to death before winter is over and spring comes and they can find bugs to feed on.
ED JAHN: The fungus basically destroys the flesh of the bats' wings, leaving them completely helpless. Scientists traced White Nose back to Europe, though for some reason, European bats aren't affected in the same way.
In the U.S., though, it's now triggered what's considered the largest wildlife die-off in living memory.
PAT ORMSBEE: This is huge. I mean we've never seen this type. It's -- it's -- it's just basically wiping out bats, not just -- I mean we think of bats as a group, but there are individual species. And we now have nine species of bats that have been affected by White Nose with virtually no resistance.
ED JAHN: White Nose is spreading fast. It's now made it to nine states, as far west as Oklahoma, and it's probably only a matter of time before it invades the Northwest.
PAT ORMSBEE: It is now closer to Seattle than it is to the location in New York where it was first discovered.
I'd like to think that White Nose Syndrome, as it gets to the West -- our bats tend to roost in smaller groups, more dispersed across the West. My hope is that it may slow down.
Maybe some of our bat species -- we do have some different bat species in the West -- maybe some of those will be resistant. We don't know. But the worst-case scenario and what we have to plan for is that's not the case.
MAN: You guys kind of stay close.
ED JAHN: The fact that White Nose made its first American appearance at the tourist-friendly Howe Caverns leads many scientists to suspect that people may have accidentally brought the White Nose fungus to the U.S. on their clothing or luggage and that people, particularly cavers, might be spreading White Nose to new places today.
MATT SKEELS: This is Lost Cave. It's always refreshing, especially on a hot summer day. You can get out of the sun and cool off.
ED JAHN: Matt Skeels is with the Oregon High Desert Grotto.
MATT SKEELS: Watch your step.
ED JAHN: A group dedicated to exploring caves of the Northwest. Almost all caves on federal land in the Eastern U.S. are now closed because of White Nose Syndrome, and Matt fears Western caves are next.
MATT SKEELS: It scares us because caving is something we love. And to be shut out of the caves that spend so much time in is like -- almost like a death of a certain lifestyle.
ED JAHN: Julie York is with the Forest Service, and she admits that talking about cave closures is not popular.
JULIE YORK: It's a lot to ask right now. It definitely is. And I don't know that we're going to ask that for all caves right now. We -- we may in the future. We don't know. It's a lot.
ED JAHN: For now, caves in Oregon remain open, with one caveat -- cavers are being asked to decontaminate.
JULIE YORK: This is what we're asking cavers to do between caves -- wash your clothes and boots and rinse them and then apply one of these for 10 minutes. And then rinse and then air dry.
ED JAHN: But there are hundreds of caves in Oregon and thousands of cavers, from the casual tourist to the advanced explorer.
JULIE YORK: You want to put all your gear into the box before you just put it into your car, so the spores don't spread in the -- in the vehicle.
ED JAHN: Matt worries that the government may be doing something here just to show that it's doing something.
MATT SKEELS: Personally, with the whole White Nose Syndrome thing, I think it's unavoidable that it's coming here.
PAT ORMSBEE: This doesn't look bad. This looks pretty normal. You can see some little spotting and that is not unusual for our bats, to see that. We call that...
ED JAHN: Perhaps the toughest pill to swallow when it comes to White Nose is that awareness of the problem doesn't mean it can be stopped. Even scientists are left to struggle with the sinking feeling that Oregon's bats may not be able to survive what's coming.
PAT ORMSBEE: To me, this is a huge loss. You know, I -- I can cry myself to sleep at night thinking about this. If we get through this without loss of species, it would be great. But it also might take a little bit of a miracle.
JIM LEHRER: You can see an extended version of that story by following a link on our website.