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The Frog Chorus Sings Out

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Some days it can seem that good news in is short supply.  But, here's a story with an up side. Over the past twenty years or so, thousands of volunteers have worked in forest preserves around the Chicago area.  They've been restoring natural habitat, and now it's starting to pay off.  The number of frogs around here is holding fairly steady. How do we know? Because a small group of naturalists wanders out into the marshes after dark to check on them.

Learn more the
Chicago Wilderness Habitat Project.

ambi: sawing sound

In the world of dedicated volunteers, these folks, from three years old to retirement age, are way out on the edge. They're about to trek into the deep forest to monitor frogs, but first, they spend a couple of hours cutting away buckthorn and weed trees from a small overgrown frog pond to make it more comfortable for the amphibians.

KRUG: Buckthorn will really suck the water out of a pond like this so it's really great that we can cut the buckthorn so that the water will stay in here longer so that the eggs will have time to mature, the tadpoles will have time to mature.

Diana Krug leads this little band of twenty or so frog monitors in the Palos preserves in southern Cook County. Having turned a stand of buckthorn into a ten-foot brush pile, they've spread maps out on a nearby picnic table, planning the evening's route through nearby wetlands and ponds.

KRUG: So, our data sheets, I put down, where we are, who's monitoring, and then which run, and we do three runs...

Tonight's is the first monitoring session of the mid-spring series, so some new people are getting trained. And the trainer, Rick Davey, is a high school senior who got involved after hearing frogs while he was running in the area for cross-country training.

DAVEY: It's more of a bigger picture thing because frogs are indicator species, so it tells you the overall health of the environment in the area.
KRUG: Is it time to go frogging? All right, it's 7:30...

The group heads off to the first listening station, clipboards in hand, to mark down their findings.

ambi: sound of walking on gravel

DAVEY: Then we're gonna come across a rise and it's gonna be right in front of you…

And, sure enough, at the first listening point, the frogs obliged.

ambi: Frog sound

KRUG: So, right now we're still waiting for the sun to go down. The sky's kind of pale and you can see the silhouette of the trees and they're really black.
DAVIS: That really predominant, that must be a peeper, right?
KRUG: Yea, the peeper is a loud, high pitched sound, and sometimes it's really overwhelming when there's a whole lot of them calling at once.

Karen Glenemeyer's on hand, too. She's the Science Director for Audubon's Chicago Region, responsible for all the monitoring in the six-county area.

GLENEMEYER: About twenty years ago, scientists around the world started noticing a really disturbing sort of anecdotal trend. They would go to these worldwide conferences and they'd start talking and they'd all be saying the same thing: 'I'm not finding any frogs at the places where I used to find hem, y'know, and this is in Australia and Central America and everywhere,' so they started thinking is this something real, is it just anecdotal, and they realized they didn't really have long-term data to know whether these downturns were normal, or not.

The group moves deeper into the forest, and frogs seem to be everywhere. Glenemeyer says this Web is so delicate. There's the problem of man's encroachment into their habitat, but they're also vulnerable to nature's cycles.

GLENEMEYER: A frog can lay 3,000 eggs at a sitting. So you've got 3.000 tadpoles and if it's a really good year and there aren't that many predators you've got a lot of new frogs coming out of the pond. Next year, they might lay 3,000 eggs and the pond dries up and not a single one makes it so you have these boom and bust cycles and you have to take a lot of data to figure out what the normal ups and downs look like.

ambi: frog sounds

We're half a mile into the forest now, and it's really dark.

DAVEY: And the one that sounds like a comb, that's a western chorus frog

ambi: Chorus frog sound

KRUG: We also hear the tree frogs which are calling from a little bit higher up, and when they start chorusing it also is very loud.

GLENEMEYER: Yes, sits up in the trees and calls just like a bird

DAVIS: Stupid question, but they climb up the trees?

Yea. They do they have really thick toes that are kind of sticky. Helps them climb up the tree. And then, when they're done calling and they feel like they've done enough they crawl back down to the water to mate and. That's what it's all about.

ambi: volunteer voices under

The monitors, rookies and veterans, figure out their ratings and begin the trek home. There are about a hundred volunteers doing this in Cook, DuPage, McHenry and Lake Counties in Illinois and in northwest Indiana, and they say they could use hundreds more.

On a warmer night, they say, with more humidity, theyd've heard more frogs, but tonight three species checked in loud and clear. A good sign that at least for now, at least in this one little place, the population of mid-spring mating frogs, is stable.

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