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To count Michigan frogs, you might visit a swamp at midnight

Mar 31, 2015

Frogs really sing in earnest after dark.

They drink and breathe through their skin without a filter and are very sensitive to environmental changes. Scientists can determine the health of an area by measuring how much the frog and toad population is increasing or decreasing – sort of like a canary in a coal mine. How does Michigan’s Department of Natural Resources count the number of frogs and toads across the state?

Volunteer ears, of course. This spring marks the 20th annual frog survey, and retired teacher Kathleen Rollins knows her Ortonville route well. She heads out to wetlands like cranberry bogs, lakes, roadside ditches, and gets into the “frog world.” There can’t be much ambient noise so it’s best to visit late at night. For the past eight years, even though the number of these indicator species fluctuates, Rollins has tracked an overall decline in frogs and toads.

What do Rollins' family and friends think when she travels to a swamp in the middle of the night? “There’s a lot of eye-rolling involved.”

As a volunteer, Rollins gets an earful of the loudest species. Peepers, which sound like a chorus of sleigh bells, are smaller than one inch but their call is deafening. Tree frogs are “the sound of the summer night … like the earth is breathing.”

In March, wood frogs that “can freeze solid in the wintertime and thaw from the inside out” begin to make some noise. Next, the sound of “somebody running a finger along a comb” can be heard from the chorus frogs. Peepers start to vocalize and later there’s the most fun: leopard frogs. “It sounds like a horror movie door opening.” American toads have one of the longest calls and are one of Rollins' favorites.

Are you the next frog and toad surveyor? Contact Lori Sargent at SargentL@michigan.gov or 517-284-6216 with your name and address.

– Annie Norris, Stateside Staff