Mud season has begun in Vermont, but soil isn’t the only thing that’s thawing. So, too, are the amphibians.
As species wake from their winter sleep — and, in some cases, soften from a fully frozen state — wood frogs, peepers, a variety of salamanders and other critters begin moving toward ponds or vernal pools to breed. Often, their journey becomes dangerous as they cross roads in search of wetter climes.
To guard against calamity, environmental groups around the state recruit and train citizen scientists to participate in “salamander crossings” on warm and rainy spring nights, during which they safely ferry the creatures from one side of the road to the other.
And for those who don’t participate, state officials and conservationists are asking motorists to consider the plight of the small, soft-bodied animals while they travel, particularly on roads near wetlands and forests.
In some areas, “there’s high mortality of the amphibians trying to cross the road,” said Jim Andrews, who runs the Vermont Reptile and Amphibian Atlas, which collects data about the creatures’ populations.
“In some cases, we’re talking over 50%,” he said.
Much of the movement takes place on rainy nights after dark, when the temperature hovers above 40 degrees Fahrenheit.
If the conditions are right, a flurry of movement can take place in a single evening, a phenomenon many herpetologists call the “big night.” In the Champlain Valley, many volunteers stationed themselves along roadways last weekend, when temperatures broke 60 degrees Fahrenheit.
But the migration isn’t over, and this week’s forecast calls for rain and ideal crossing temperatures in many areas of the state.
“Movements will be happening this week,” said Luke Groff, a herpetologist with Vermont Fish & Wildlife Department. “Not across the whole state — it’s sequential. You can think of fall leaf color. It kind of moves north with time.”
Groff, who said he participates in the crossing efforts with his kids each year, encouraged amphibian enthusiasts to stay safe during their efforts. He urged participants to stick to back roads, pull cars fully off the roadway, use hazard lights, wear headlamps and orange vests, and use a buddy system.
Bonnyvale Environmental Education Center in Brattleboro has been organizing salamander crossings for 20 years. The events began with nature tours, during which members of the organization took interested Vermonters to see salamanders in vernal pools on rainy nights.
“We then realized, oh my gosh, we might be driving over them as we do that,” said Patti Smith, a naturalist educator at Bonnyvale.
Ever since, they have organized to find areas where amphibians most commonly cross the roads and enlist volunteers to help them do so safely.
Bonnyvale is one of a handful of entities that organize crossings. Others include the North Branch Nature Center, which posts a map of common amphibian crossings; the Cornwall Conservation Commission, which has posted links to amphibian crossing trainings; and the Hartford Salamander Team, which has published its own map of prime crossing locations.
“We need all the help we can get out there,” Smith said.
Andrews, of the Vermont Reptile and Amphibian Atlas, said efforts to save the creatures from cars can prove to be tricky. The busier the road, the more dangerous the activity becomes for people, particularly children — but busier roads are often where more amphibians die from car traffic.
He wants to see the state install underpasses, which allow amphibians to cross safely under the roads without human assistance. Only one underpass exists in Vermont, in Monkton, Andrews said.
In that case, stars aligned to make the project possible, he said. But the projects are expensive and often make the most sense to install when the road is already being repaved.
Cameras in underpasses across the Northeast show they’re effective, Andrews said.
“There has been a huge reduction in the mortality of amphibians crossing those roads,” he said. “We can see hundreds of amphibians going through those underpasses on migration nights, which is very cool.”
Data from volunteer efforts could help officials better understand where frogs and salamanders typically cross most, and where underpasses would be most helpful, Andrews said. The more detailed the data, the better, he said.
And, data aside, Andrews said Vermonters who have grown tired of winter weather have another motivation to brave the rain.
“This is an opportunity to see a real clear sign of spring,” he said, “and a cool migration wildlife event with some really cool-looking salamanders.”
