04-05-2025
Amphibians on the march for their Big Night
May 3—On warm, rainy spring nights, hundreds of volunteers stake out roads across Maine keeping watch for any movement.
Their goal is to do what they can to usher some of the state's smallest creatures across to the road to ensure the next generation of amphibians will live to take the same trip in years to come.
Maine's annual spring migration brings throngs of frogs and salamanders down from the forested uplands to shallow seasonal or vernal pools, where amphibians gather to breed each night.
But the migration paths often take them across the state's network of paved roads, putting the frogs and salamanders at risk of death from traffic.
Greg LeClair, biologist at Maine Department of Inland Fisheries and Wildlife, sought a solution to the carnage. In 2018 he founded Maine Big Night, a community science project that invites volunteers across Maine to help amphibians safely cross dark roads while collecting data to support long-term species survival.
Derek Yorks, wildlife biologist at Inland Fisheries and Wildlife, said it's special to see synchronized migration between the various species.
The most common migrating species in Maine are spotted salamanders, red-backed salamanders, blue spotted salamanders, four-toed salamanders, wood frogs and spring peepers, who can be heard nightly. On April 20, a law was passed to designate the spring peeper as Maine's official state amphibian.
"They're all a little different, but their habitat is shared and the migration is shared," Yorks said. "So it can be quite the spectacle, definitely worth seeing for yourself if you get a chance."
Opportunities to see amphibians aren't exclusive to nighttime. On a recent Saturday, the Sebasticook Regional Land Trust and Maine Master Naturalists held a vernal pool walk at Freedom Forest Reserve in Freedom, and the Kennebec Valley Land Trust hosted a vernal pool field workshop at the Ezra Smith Wildlife Conservation Area in Mount Vernon. They were just two of several vernal pool exploration events scheduled in April.
These events increase human understanding of amphibians, said Noah Charney, assistant professor of conservation biology at the University of Maine who helped found the Maine Big Night nonprofit organization.
"The understanding that people walk away with of what species are out there and what they need to survive, and understanding vernal pools and amphibians, I think, adds a layer of broader societal understanding and acceptance," Charney said, "and knowledge about what is in our world and what we need to do to protect it."
While migration occurs over multiple nights, the Big Night is the night where conditions are optimal: rainy weather, wet roads and a temperature in the upper 40s or 50s.
On those nights, amphibians race to be first to the pond so their larva can develop and metamorphosize before the pond dries up, Charney said.
"They're trying to get there as soon as they thaw out, as soon as it's warm enough and wet enough for them to get there, and be the first to lay the eggs," Charney said, which are then fertilized. "So it's a race for these vernal pools in the early spring — the first warm, rainy night — although there's often a trickle of salamanders and frogs moving on a variety of different nights. But in general, the first warm, rainy night, they all try to get down to the ponds."
This year, rainy nights throughout April brought earlier movement in southern Maine and a large peak night in central and northern Maine on April 15. Volunteers shared updates on species movement on Maine Big Night's Facebook page, noting location and weather conditions. The social media group is also home to hundreds of photos and videos of brightly colored frogs and salamanders, often perched in the hands of volunteers outfitted with headlamps and clad in reflective safety vests.
Maine's amphibian species live the majority of their lives underground anywhere from a couple hundred to 1,000 feet from vernal pools. They venture out only to breed, making spring the perfect time to spot reclusive species before they return home.
Charney said some amphibians stay in their hiding places for years.
"If it's deep into late April, May, and there hasn't been any warm, rainy nights, at some point they're going to try to take whatever they can take to get down to those ponds," Charney said. "Or they'll decide to just skip the year entirely and wait until next year to migrate. Spotted salamanders in particular will do that."
Synchronized amphibian migration happens across the Northeast each spring, but Maine Big Night was the first statewide, volunteer-led community science event, according to its website. Data has been recorded on over 20,000 amphibians since 2018.
Charney said large-scale community science projects like Big Night reveal the pros and cons of human interaction with wildlife. Most times, he said, the positives win out.
"There can definitely be a negative, direct impact felt by amphibians sometimes when there's too much interest in them," Charney said. "But I think that overall, in the bigger picture, I'd rather have more people excited about the amphibians and learning about them and understanding them and the kids playing with them — I think that in the long run, it has more positive impacts than the direct use of that wetland that night."
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