RUMFORD – Froggie didn’t go a-courtin’ last week because of heavy snow. But, when the annual male amphibian search-for-sex begins, Maine Audubon intends to have more than just female frogs within hearing range. On several evenings through early summer, humans will be listening and noting what they hear during the 11th annual Maine Amphibian Monitoring Project.
As of early this week, one citizen-scientist volunteer and a friend were needed to conduct two-hour roadside surveys in each of 17 areas in rural Maine.
“We really have trouble getting people in Aroostook, because it’s really rural, and mud season is a problem,” project co-coordinator and University of Maine wetlands ecologist Aram Calhoun said by phone Tuesday afternoon in Orono.
After passing an online quiz on frog calls, volunteers will conduct surveys first in early spring, listening for wood frogs and spring peepers, Maine Audubon wildlife biologist and project co-coordinator Susan Gallo said in a Monday report.
In late spring, ears are tuned to American toads, northern leopard and pickerel frogs. In early summer, the other four frog species sounding off are gray tree, green, mink and bullfrogs.
Volunteers will make 10 stops along their routes, waiting five minutes at each and noting the frog species they hear.
“They’re not hard to distinguish, because they don’t all sing at the same time. There are nine species here, compared to in the 30s in the South. So, Maine’s got it easy in terms of listening,” Calhoun said.
Concern over their vulnerability and a lack of information about frog populations spawned Maine’s frog assessment project in 1997 by Maine Audubon and the Maine Department of Inland Fisheries and Wildlife.
Because amphibians are sensitive to changes in water quality, ultraviolet radiation and land use practices that degrade or eliminate habitat, they are great indicators of environmental quality changes.
Wood frogs, which sound like quaking ducks, normally emerge by the end of March and early April in southern Maine. Not so this time.
“They’re going to be late,” Calhoun said of the frogs, which have a natural glucose antifreeze that protects their cells, allowing them to survive Maine winters.
“Through the winter, they are literally frozen solid in leaf litter and, once they thaw out, they head for vernal pools. Their cue is melting snow and warm water. They know it’s time when it gets warm, but if we get a warm spell like we did in January, wood frogs will come out and freeze to death. Their antifreeze only works when they’re frozen solid. In false thaws and late winters, they die,” she added.
Other frogs hibernate in mud in lakes and ponds and must wait for warmer temperatures.
“Global warming is going to change all the breeding patterns,” Calhoun said. “I think part of the pattern of global warming is unpredictable weather patterns. It’s going to be in the teens and 20s tonight, but it was 65 to 70 in Portland, so we might find a very reduced wood frog population this year.”