Big Night
On the first warm and rainy nights of spring, some of the most elusive peatland dwellers come out of hiding. They have been buried beneath logs and leaf litter, waiting for the right conditions to make their annual migration.
They are crawling and hopping to vernal pools––areas where water is only present for a short portion of the year––to mate and lay eggs. And they need ideal conditions to be able to survive the journey.
Cooler fall temperatures drive amphibians to find cover under leaf litter and beneath logs. They will freeze overwinter, thaw in the spring, and then set out on an epic journey to reach their mating grounds.
Vernal pools are relatively safe areas for young salamanders to develop, without the threat of being eaten by fish. But reaching these safe havens can be a big challenge.
Amphibians breathe––at least in part––through their skin, as long as their skin does not dry out. For most of their life cycle, they remain close to ponds, lakes, and streams. But when they make their spring migration, they run the risk of drying out.
A spotted salamander crosses a forest floor strewn with pine needles on its way to a vernal pool.
A persistent, soaking rain is the key to a successful migration. As soon as the conditions at sundown are warm and wet enough, salamanders and frogs leave their upland forest habitats in search of a suitable vernal pool––often the same pool they have returned to year after year. Perfect conditions can trigger a mass migration––what salamander and frog enthusiasts call a “Big Night.”
A spotted salamander, nearly eight inches in length, crosses the road on its migration to a vernal pool.
Even with perfect conditions, salamanders and frogs face many challenges on their migration. Some will travel up to a mile to reach their spring mating grounds. Along the way they are vulnerable to nocturnal predators like owls, foxes, and skunks. And in areas where busy roads have interrupted their migratory pathways, mortality rates from vehicle collisions can be high enough to threaten the viability of amphibian populations.
Spring peepers are among the first of the amphibians to emerge in the spring. As their name suggests, they create a high-pitched “peep” to attract mates.
Lending a helping hand
While road crossings present a significant challenge, many communities have banded together to help salamanders and frogs cross the road. Volunteer groups gather on the first rainy and warm spring nights, helping amphibians cross the road along critical crossing areas. In some areas of the country, entire roads are closed to vehicle traffic for the duration of “Big Night” season. Where road closures are not practical, some counties have built underpasses for amphibians to safely reach their breeding grounds. These actions, paired with habitat protection and restoration, will help ensure these amphibian populations are here to stay.
A spotted salamander perches on a hummock of moss on the edge of a vernal pool. The pattern of their spots is unique to each individual. Often adult salamanders will live 20 years, with some living as long as 30 years.
Amphibians in peril
The awe-inspiring phenomenon of the “Big Night” migration has mobilized conservation efforts in recent years––but it will take more than road closures and wildlife underpasses to secure the future of amphibians.
Globally, nearly half of all amphibians are at risk of extinction.
Habitat loss, pollution, and climate change are threatening amphibian populations around the world. Given amphibians are some of the most vulnerable species to environmental degradation, they act as a warning for other species who are more resilient.
Peatlands provide critical wildlife habitat, including safe haven for amphibians. Preserving the transition between ecosystems––here, where the peatland meets the forest––ensures wildlife remain connected to habitat they require during each life stage.
Taking action
Habitat restoration, paired with conservation efforts designed to promote habitat connectivity, will be essential to ensure amphibian species continue to thrive.
By supporting conservation efforts in forestlands and wetlands, including northern peatlands, salamander and frog populations will continue to thrive in the habitats they depend upon during each stage of their life cycle.
Four-toed salamanders are lungless, breathing entirely through their skin. They lay their eggs underneath sphagnum moss, often in group nesting sites. Mothers will guard their eggs until they hatch. Four-toed salamanders have the ability to regrow their tails after they have been detached, helping them escape predators. They have dark spots on their white bellies, and as their name suggests, they have four toes on all four limbs. Fully grown, they reach 2-3 inches in length.
“Big Night” Webinar with Natural Habitat Adventures and World Wildlife Fund
Interested in learning more about the “Big Night” migration, and how you can help support amphibian migrations? Watch Expedition Leader Charlie Reinertsen discuss this phenomena as a part of Natural Habitat Adventure’s Daily Dose of Nature webinar series.
