FAYETTEVILLE OBSERVER (N Carolina) 19 February 08 Listen to what frogs are telling us (April Johnston)
Jeff Marcus tips his head back and stares.
The moon’s out. The black sky is stained with thin, patchy clouds.
It’s days after a good rain and — he checks his yellow, handheld thermometer — the temperature is about 50 degrees now.
He nods.
Yep, conditions are right for the early breeders. He stares into the inky distance and waits.
Peep. Peep. Peep.
“Hear it?” he asks.
It’s the high-pitched whistle of the spring peeper. And then, suddenly, something else, off to the right. Like fingers running over the teeth of a comb. It’s the upland chorus frog.
“Right on cue,” Marcus says with a grin.
He patiently waits for the third member of the nocturnal chorus to call.
Silence.
He pulls out his pencil to mark it down.
It’s Friday night. Marcus is wearing a head lamp and carrying a clipboard. It’s his first outing of the season, so he hasn’t put the sign in his car window yet, the one that announces he’s part of important scientific research.
So, when cars whoosh by, it’s hard to know what the drivers think of this man parked along the road’s sandy shoulder, his hand cupped over his ear.
“People do look at you a little funny,” he admits.
Officially, Marcus is a supervisor at the North Carolina Wildlife Resources Commission. But tonight, he’s also a volunteer, driving a route in Vass for the commission’s Calling Amphibian Survey Program.
As a volunteer, his assignment goes something like this: Stop along 10 spots on the route, three times a year. Listen for frog and toad calls for five minutes. Count each call that’s heard.
Another commission scientist, Jake Marquess, rides shotgun. He’s not an official volunteer, but he’s a frog call ringer.
Last season, he distinguished between the Northern cricket frog and the Southern cricket frog, whose calls sound like pebbles being clicked together — and pebbles being clicked together a little faster.
Marcus is good, but not that good, he says.
Honestly, he’s always been more interested in birds. He thinks they’re prettier and far more charismatic than the average amphibian. He faithfully walks a roadside route for the Breeding Bird Survey — a decades-old program that monitors bird populations in North America — every summer.
The BBS, as it’s called, served as a rough model for the frog survey. But while the bird survey has thousands of volunteers, many of the state’s 139 frog survey routes are still unmanned.
“I think more of the general public cares about pretty birds than slimy frogs,” Marcus says with a chuckle as he approaches another stop.
But frogs are becoming more than just the prey of little boys with grimy hands and are taking their rightful place as one of the world’s top environmental indicators.
Sort of like the canary in the coal mine, frogs sense environmental danger before humans do. Partly, it’s because they breathe through their skin. Partly, it’s because they need wetlands and terrestrial land to live.
So tracking their whereabouts and populations over time gives scientists an idea of what’s going on in that part of the country.
And the central swath of North Carolina, where Marcus drives his route, is a herpetologist’s promised land. It’s where the Piedmont and Coastal populations overlap and where a few Sandhills specialists make their home. About 25 of the state’s 30 species live here.
But this early in the season, Marcus expects to hear only the peepers, the chorus frogs and a few leopard frogs.
Or at least one. Six stops in, they’re proving stubbornly elusive.
“This will give you an idea,” Marcus says, twisting the volume knob on his car stereo and clicking a few buttons. He keeps a copy of “Frogs and Toads of North Carolina” cued in his CD player so he can brush up on his calls as he cruises.
A moment later, an obnoxious chuckle, like a hyena, blasts through the speakers.
“That’s the leopard frog,” he says.
On a typical night, that call wouldn’t be so difficult to pick out. But Friday night is noisy. Trucks rumble, creeks bubble, owls hoot. Marcus’ boots crunch dead leaves at the edge of a pond when he tries to scoop out a few peepers.
And, at one of the last stops of the night, near a farmer’s pond, the neighborhood dogs are howling.
In the silent moments when the dogs stop to catch a breath, Marcus and Marquess pick out the whistling peepers and the trilling chorus frogs.
And then, could it be?
“Did you hear that?” Marcus asks pointing into the distance.
“There it is,” Marquess answers.
In the world of frog surveying, the first call of the season is like baseball’s first pitch.
The men grin and lean in toward the pond for another listen. But the leopard frog chuckles only twice before the howling dogs drown it out.
Marcus sighs and shrugs.
“High canine diversity in abundance out here, too,” he deadpans.
Listen to what frogs are telling us