Originally created 03/19/00

Counting frogs' croaks will help your neighborhood



If you're hearing spring peepers around your neighborhood creek or pond, the U.S. Geological Survey would like you to do a little scientific counting. It eventually could tell a lot about the environmental health of your area.

Through a program called Frogwatch USA, volunteers around the country are lending their ears to listen for the courting calls of frogs and toads, and turning over the results of their counts to scientists attempting to track the size and health of amphibian populations.

Biologists worldwide have been noticing declines in frog and toad populations for more than a decade, with several species having gone extinct and other species severely diminished in numbers.

"Understanding the decline of amphibians is crucial to uncovering how society's activities affect water quality, wildlife habitat and overall health of the environment. They're very important sentinels," said Sam Droege, a wildlife biologist and amphibian researcher with the U.S. Geological Survey's Patuxent Wildlife Research Center in Laurel, Md.

There's no need for nets or waders to count for Frogwatch, just a good set of trained ears, a thermometer, a watch, a flashlight and paper and pencil, and a promising patch of wetland.

"Most people can learn to distinguish the calls of all the frogs in their area in a day or two. Generally, no one site will have more than 10 or 12 species," Droege said.

Tape and CD recordings of frog calls for each region of the country are sold commercially. They also are available in many libraries. Some can be downloaded from Web sites.

Gideon Lachman, coordinator of the Frogwatch project, said volunteers who have trouble identifying what they're hearing pondside can take along a tape recorder and then compare the sounds on the tape with a professional recording back home. "If they're really stuck, they can mail the recording to us," Lachman said.

Frogs are counted using a four-level calling index, ranging from no calls to a "constant and overlapping chorus" of frogspeak. Results can be returned to Frogwatch USA electronically, or by regular mail.

Started last spring, Frogwatch USA is monitoring more than 500 sites in 48 states -- Rhode Island and Utah excepted. While most volunteers work on their own or with their family, other partners include schools, Scout troops and conservation groups.

"... The best monitoring would be done once or twice a week throughout the breeding season, which depends a lot on location, but can run from February in the deep South up through July," Lachman said.

Droege said the volunteer effort won't replace more random surveys done by biologists "because our sample coverage is determined by where people decide to listen."

The real payback "may not come for 10 years or more. But if people stick with their wetland for a number of years, we should have some really good data that will help us sort out the natural variation in frog populations and help us figure out when external influences might be at work."

For more information: http://www.Frogweb.gov

Lee Bowman covers health and science for Scripps Howard News Service. E-mail BowmanL@shns.com