They stand, one hand cupped behind each ear, as if trying to imitate an elephant, on the edge of a mosquito-infested marsh.
And on a quiet night like Wednesday, when about 30 froggers at the J.B. Starkey Wilderness Park all faced the same way and struck this pose, the low roar pulsing across the swampy field can become a chorus of distinct voices. To the left, the piercing, chicklike chirps of a southern spring peeper. To the right, the banjolike twang of a bronze frog.
"You can hear about two times as much this way," guide Katie Mac Millen called out. The hikers trailing her, mostly retirees, immediately cupped their ears forward. Nobody dared break the quiet at first, but a few murmured under their breath. Mac Millen, an environmental educator at the Starkey Environmental Education Center pushed on.
"Oh, I can hear it."
"A barking tree frog, over there. That clump of trees!"
For froggers, listening hard and well is the best chance for identifying the frogs that populate any given area. And according to conservation biologists at the Hillsborough River Watershed Alliance, it may also be native frogs' best hope for survival.
The Starkey froggers had braved an evening rainstorm and what felt like thousands of mosquitoes to attend a frog identification training sponsored by the alliance's Frog Listening Network. By teaching "citizen scientists" to identify frog calls, count frogs and e-mail their findings to the network, the alliance hopes to track the health of west-central Florida waterways, biologist Lance Arvidson told the Starkey group Wednesday night.
As his co-presenter, 9-year-old frog enthusiast Avalon Theisen, told the audience: "Now the frogs are starting to die out, and that's a problem not just 'cause they're cute but because they're an indicator species," referring to animals that alert scientists to regional identification as well as trends in disease and climate shift.
.Disturbed areas like urban Tampa are swarming with invasive species such as the Cuban tree frog, which sounds like the squeak of a wet shoe, and the marine toad, which has the rolling, soft warble of a screech owl.
Both eat as many native frogs as they can, Arvidson told the group near the beginning of his presentation, which covered 14 frogs, three toads, which generally distinguish themselves from frogs as being somewhat more terrestrial, and three invasive species and their calls - everything from the pig frog, which grunts like its namesake, to the Florida gopher frog, whose call Arvidson describes as a creaking door in a haunted house.
Beyond the environmental lessons of frogging, Arvidson had another message for his listeners: Frogging isn't just important. It can be fun.
"You might start hearing some things and you might not have any idea what it is," he said. "Frogging enriches the whole experience of going out at night."
On the totem pole of animal-watching activities, frogging has to rank among the least glamorous of activities. For one thing, most call from where they cannot be seen. And frogging is best done in a dank marsh, with mosquitoes everywhere, in the dark, in the rain. The wetter, the better.
"Birders get up in beautiful, crisp early mornings and they go out and do their birding," said Frog Listening Network coordinator David Sumpter. "Frogging, it's not quite as sexy as going out birding."
Still, Sumpter and Arvidson say they have a dedicated network of volunteers who go on night hikes a few times a month and count frogs, many of them retirees who have always wondered where those noises in their back yard are coming from.
"I just wanted to know what I was hearing," said Maria Valentine, an Audubon Society member who has attended a few of Arvidson's sessions. Since she began frogging, she has learned to listen especially hard when the moon rises and the frogs get louder. "It's pretty exciting to notice things like that."
Avalon's parents feel the same way. Ever since Avalon started showing interest in frogging, they've been listening to a CD of frog calls every time they get in the car.
"You can hear it on CDs, but it's nothing like the experience," Deborah Theisen said, watching her daughter - who wore a "junior herpetologist" badge and vest she got for her birthday - dart around the trail catching nervous-looking frogs.
"This is huge," saidfirst-timefrogger Keith Theisen. Avalon chased a toad across the trail until it was stopped by another hiker. It squirmed as she picked it up and Arvidson shone a flashlight on it.
"A southern toad," he said to the froggers. "See the little horns?"
A little reluctantly, Avalon let the toad hop away. A few minutes later, froggers cupping their ears forward could hear it and its fellow toads, trilling in the dark.
Vivian Yee can be reached at (727) 869-6236 or firstname.lastname@example.org.
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For more about the Frog Listening Network, e-mail Lance Arvidson,email@example.com, or go tohillsborough.wateratlas.usf.edu/fln.