The annual amphibian migration
Spring in New England provides us with many wonders and if you are lucky enough to witness “Big Night,” you will never forget it. During the first warm (above 40° Fahrenheit) rains of spring, some frogs and salamander species migrate in large numbers from the forest uplands, where they have overwintered, to the temporary woodland pools where they reproduce.
Many amphibian species, including wood frogs and spotted salamanders, require both wetlands and forests to survive. These animals spend most of the year in the forest, hiding under logs and leaf litter. But in the spring they migrate to vernal pools to find a mate and lay eggs. These temporary pools, which dry up later in the summer, provide a relatively safe environment for the amphibians because they do not support fish, which would otherwise predate on the young amphibians.
Many animals will return to the place they were born to lay their eggs. The young animals are then in a race against time as they must hatch, find food, metamorphose and become an adult able to navigate the forest before the pool dries up. And there are of course predators other than fish, including racoons, mink and herons, which will frequent these pools for water and food.
During Big Night, you may witness the migration and mating of hundreds of amphibians. All this movement – the amphibians migrating, the predators drawn to the pools in search of food, and the young amphibians that disperse from the pools in the early summer – are key components of nature cycling and redistributing carbon and nutrients throughout the woodland habitat. Thus the pool, and the animals that use it, represent both a supermarket and distribution system for the entire woodland habitat.
Because human activity can threaten vernal pools and the animals that depend upon them the state of Maine passed regulations in 2006 protecting vernal pools and the animals that need them for survival. For more information about the importance and protection of vernal pools, click here.