It may not look like it now but frogs will soon be calling in southwest Michigan. In only a few weeks, the Michigan Department of Natural Resources will begin its 18th annual survey of the state’s frog and toad population. The project depends heavily on volunteer “citizen scientists” to gather the data.
DNR wildlife biologist Lori Sargent is in charge of the survey that began in 1996. At that time, Sargent says many species of amphibians were in sharp decline around the world. The Michigan survey was started to gather yearly data measuring how well frogs and toads were doing here. Sargent says maintain the survey over many years is important to keep an eye on the health of the state’s wetlands. Although there have been “dips” from year to year, she says survey data suggest that Michigan’s frogs and toads are holding steady overall.
Sargent says the survey relies on volunteers because there aren’t nearly enough professional biologists to cover the sites that need to be monitored. The volunteers are assigned to routes that have ten sites: bogs, ponds, or fens. They listen for five minutes at each site, hoping to hear the calls by male frogs marking their territories and seeking mates. The volume of the “songs” lets volunteers get a rough estimate of their numbers. Each species of frog has its own distinct call, just like birds.
Some kinds of frog begin calling in the Lower Peninsula by mid to late March while others don’t begin singing until June. There are 13 species of frogs in Michigan. Sargent says no site will have all of them but that some can have as many as seven or eight.