Why did the human help the frog cross the road?

April 4, 2017, 12:50 p.m.
spring peeper frog
Photo: Mark Nenadov/flickr

When it starts to warm up in spring after a cold Vermont winter, frogs and salamanders respond by starting to move. They emerge from their spots under logs and other cover where they've waited out the winter, and they travel to breeding pools on rainy spring nights.

The danger is that these migrating amphibians — which typically include spring peepers (like the one above), wood frogs and salamanders — often have to cross busy roads and highways to get where they need to go. Many don't make it, getting killed by cars as they try to cross.

"Sometimes it's a slow dribble of animals," biologist Steve Parren of the Vermont Fish and Wildlife Department tells MNN. "I have experienced a few nights when the ice is largely out of the ground and a heavy rain causes a stampede of amphibians from upland woods to wetland pools on the other side of a busy road. I actually could hear the wood frogs hopping toward me through the wood and the salamanders swam across the road because the rain water had created a sheet of water over the pavement."

Parren has documented large numbers of animals that have met their demise on roads and highways. Over two consecutive nights, he estimated that more than 1,000 animals died at one site he monitors where animals move across a .8-mile section of the road. The biologists call these areas "hotspots" where they've detected large numbers of amphibians moving across the road.

Wildlife officials and volunteers work to manually slow traffic and manually carry amphibians across the roads at hotspots. The Vermont Fish and Wildlife Department is asking drivers to report any similar large groups they see. They're working to build culverts and wildlife barriers to help wildlife move across the road more safely. The town of Monkton spent several years raising more than $300,000 on a highway project to help the animals cross.

Vermont biologists worry that the fatal crossings could be hurting the decline of the species, Parren says.

"We do worry about such high mortality impacting the population and wonder if it can survive over time."