Hundreds of volunteers across the state will be brushing up on their identification of the Northern Leopard Frog's mating call in coming weeks. Not for personal use, but for the benefit of science. They are preparing for the Minnesota Department of Natural Resources' (DNR) Frog and Toad survey, a project that calls on volunteers, or citizen scientists, to go out, listen to frogs, and report what they hear.
Wood frog calls sound like wooden blocks knocking together with a rhythm reminiscent of clucking chickens. The Minnesota DNR is calling on volunteers
Volunteers can choose from 250 routes, or sample sites, throughout the state. Believe it or not, volunteer slots for nearly all of the routes get filled.
"It is a little competitive," said Volunteer Coordinator Heidi Cyr. Routes near the Twin Cities especially fill up right away. There are still open routes in the local area, at Whitewater State Park, Root River State Park, and La Crescent.
Volunteers study the calls of local frogs, take an online quiz to verify that they know their "ribbits," listen to calls at stops along their route, and measure the frequency of each species' call as intermittent, overlapping, or continuous.
Volunteers go out at night to listen, on cloudy and humid nights, if possible. Cyr admits it can be a little spooky to go by yourself. She was riding her bike along a listening route one year when the frog calls starting playing tricks on her. "I swore someone was chasing after me. It sounded like someone was yelling and running behind me." Cyr stopped—surely it must have been tempting to pedal faster—she realized it was just the frogs.
In any case, Cyr recommends going with someone else."We get a lot of parents who have kids who love frogs and toads. Others are naturalists who want to help," she said. Some couples participate, going out counting frog calls on a date—or something.
"We have people who have come back for 10 years." Cyr said.
The project has been going on for nearly twenty years and is part of a nationwide survey of amphibians by citizen scientists. The results give biologists an idea of the expansion and contraction of frogs' ranges. The survey has helped outline the spread of invasive bullfrogs, the loss of frogs due to development, and even, in one case, has lead to discovery of a previously unknown population of the endangered Northern Cricket Frog.
Survey sites in Northern and Western Minnesota are often unfilled, Cyr said, though some people like to use visiting the survey sites as an excuse to explore the state.
All of the routes can be accessed car; no waders required. Interested parties may learn more about the survey on the Minnesota DNR's website http://www.dnr.state.mn.us/volunteering/frogtoad_survey/index.html. The map of available routes is at http://on.doi.gov/b9uriF, and the frog call quiz is available at http://www.pwrc.usgs.gov/frogquiz/. Volunteers are accepted through the beginning of the survey, April 15.