Defenders Magazine

On the Ground: Why Did the Amphibian Cross the Road?

by Madeline Bodin

© Chris Slesar

Big drops of rain explode as they hit the asphalt in the beam of Steve Parren’s headlights. Everything else is darkness. Parren drives his Subaru wagon at a crawl on the thin shoulder of Monkton Road in Monkton, Vermont, emergency flashers blinking.

He’s keeping an eye out for creatures the size of cigars and cigarette butts on the pavement. Suddenly he parks the car, and he and three passengers leap out.

A spotted salamander, about six inches long, is marching across the road like a Dixieland trumpeter, head held high, each leg raised with precision, head and tail swinging back and forth.

Nearby, wood frogs leap over the double yellow line. Normally their backs are tan and they sport a dark brown “robber’s mask” around their eyes. But so soon after emerging from their winter hibernation, they are pale and ghostly. Next to them, spring peepers—tiny tree frogs—look like leaping dimes in the car’s headlights, and hybrid salamanders—a mix between Jefferson and blue-spotted salamanders—slither.

It’s a scene repeated every spring across Vermont—and other parts of the world. The season’s first warm rains prompt many amphibians to leave dry land and head to the nearest body of water to mate and lay eggs. But more and more, they must cross roads to get there. Many of them won’t make it.

Tonight, a group of 13 volunteers is quickly scooping up these animals and carrying them safely across the road in loose fists. Meanwhile, Parren, head of the nongame and natural heritage program of the Vermont Fish and Wildlife Department, is busy flicking a powerful flashlight at the unmoving lumps on the pavement. A short flash of light is usually all he needs to make an identification—spotted salamander, wood frog, peeper or hybrid salamander. He’s all too familiar with what these animals look like as roadkill.

Parren, who started recording the number of amphibians crossing the road at this spot 10 years ago, tallies tonight’s animals, dead or alive, with pencil marks in his notebook. Each animal is coming from the hillside on the east side of the road where they spend the winter hidden under fallen leaves or in tunnels below the frost line. Across the street lies Huizenga Swamp, where slabs of weary ice still float in late March. There, the amphibians will mate and lay their eggs—if they survive the crossing.

Tonight about three-quarters of the animals will make it. But Parren typically sees more dead animals than living, and the numbers add up with each rain. One night last year he tallied more than 1,200 road-killed amphibians.

“There are lots of sites like this one across the state,” says Jim Andrews, a herpetologist at Vermont’s Middlebury College. What makes this site unusual, he says, is the diversity of amphibians crossing the road at one time, the presence of the blue-spotted salamander—a state-imperiled species—and the traffic.

The road carries an average of 1,600 cars a day. “By the rest of the country’s standards it may not be such a busy road,” says Chris Slesar, a member of the Monkton planning commission. “But by Vermont standards, it is.” The amphibians can’t breed fast enough to keep pace with the number of animals killed by cars each year. “That population is not going to survive,” he says. “Once it’s gone, it’s gone. The whole region will be out of an incredible resource.”

Amphibians play a vital ecological role by moving nutrients—in the form of their own bodies—from rich aquatic habitats to the relatively nutrient-poor surrounding uplands. They also serve as a crucial link in the food web by eating insects and by being eaten by hawks and foxes, for example.

To save this diverse group of amphibians, several organizations have banded together to raise money to build amphibian underpasses or “toad tunnels” in the eight-tenths-of-a-mile stretch of road most heavily traveled by amphibians.

Last year, Defenders of Wildlife supported their efforts when the town government and local conservation organizations applied for a grant from the Vermont Agency of Transportation, where Slesar has a day job as an environmental specialist. 

The grant would enable the building of five culverts under the road, about 200 feet apart. Typically, amphibian underpasses are at least 2 feet deep and 2 feet wide. They are topped with heavy metal grates that lie flush with the surface of the road. The grates provide light and moisture, while retaining walls on each side of the road funnel the animals to the culverts.

Although amphibian crossings are gaining some ground in other states, this project stands out for two reasons, says Scott Jackson, a biologist and expert on amphibian crossings at the University of Massachusetts Extension Service-Amherst. First, it draws on the wisdom of both road engineers and biologists—many projects make do with one or the other. Second, the long history of surveying amphibians at the site means the results will be clear. “People are going to keep an eye on this project,” says Jackson.

Unfortunately, the grant application wasn’t approved this time around, says Slesar, but they will try again next year. “The hand-carry method is not the answer,” he says. “We can’t mobilize a group for every cloudburst in the spring. It’s dangerous on that road, and it’s not as effective as a solution that includes culverts and walls.”

Slesar is now working on getting funding from state and federal agencies that will enable the building of at least one 25-foot amphibian crossing under Monkton Road in the next two years to protect some of the traveling amphibians while also showing future funders how a culvert system works.

In the meantime, at 11 p.m. on this rainy spring night, most of the volunteers on Monkton Road have gone home. But Holly Lukens, a Monkton Road resident and self-described “big fan of salamanders” does not want to stop. She and Parren drive back to the crossing site after dropping off other volunteers. The rain has turned into a misty drizzle.

“Frog!” calls Lukens.

“Peeper!” says Parren at the same time.

He stops, opens his car door, scoops up the inch-long animal in his hand and steps to the roadside. A passing car drives over the spot where the frog had just been. Parren places the creature on the edge of the still-brown lawn. The frog is safe; the swamp is just a few hops away. “That’s a lucky one,” says Parren, getting back into the car.