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This is Scientific American's 60-Second Science. I'm Cynthia Graber. This will just take a minute

Declining frog populations are considered an indicator¹ of environmental damage. But new research finds that frogs might be doing even worse than we thought. Because the volunteers who count frogs by their sounds may be overestimating².

The North American Amphibian³ Monitoring Program is the country’s largest frog-counting system. Volunteers listen for frogs, identify the species, and give population estimates. They’ve been doing this for over a decade.

Ted⁴ Simons from North Carolina State University and colleagues put recordings⁵ of frogs, like this wood frog, in the field to test the volunteers. They call it Ribbit Radio.

Many volunteers ended up with false positives—they named frog species whose calls weren’t being played. So there may be fewer frogs, or less variety, than the surveys suggest. The results appear in the journal Ecology.

Simons is working with the U.S. Geological Survey—in charge of the amphibian monitoring—to account for these false positives, and to better train the volunteers—so they don’t write down “chorus frog”when all there really was were pickerel frogs. Apparently⁶, it’s not easy being green, for humans either.

Thanks for the minute. For Scientific American's 60-Second Science, I'm Synthia Graber.