AMHERST, Mass. - One rainy night in the next few weeks (perhaps as early as March 16), while most people are watching television or sleeping, millions of salamanders and frogs will skitter across Massachusetts and many other states.
Scott Jackson, wildlife biologist in the department of natural resources conservation and extension educator for UMass Extension, says several important amphibian species soon will emerge from underground burrows, or wherever they live during the winter, to begin their annual migration to wetland areas. Their trek will herald the beginning of the amphibian-breeding season, timed to occur when the temperatures and the rain are just right.
"Forty degrees and pouring rain isn''t what most people think is a good night to go out, but it suits salamanders and some frogs just fine," says Jackson. He says the animals move in the dark and in the rain to avoid predators and keep from drying out. Plus, a steady rain signals the creatures that vernal pools will be filled with enough water to accommodate them.
Vernal pools are small bodies of water—sometimes mistaken as overgrown mudpuddles— which appear in the spring, then disappear. The pools may be in wooded areas, open fields, or even in suburban neighborhoods.
"The amphibians like to go to the breeding areas early in the season, usually in March, because the earlier they breed, the longer their young have to grow before the pool dries up," explains Jackson. He says amphibians prefer vernal pools to other bodies of water, where fish might get in their way.
In Massachusetts, three mole salamander species are preparing to migrate: spotted, Jefferson, and blue-spotted. The spotted salamander is the most commonly seen; the other two are listed as either species of special concern or threatened species in Massachusetts. Wood frogs, the most cold-adapted amphibian of North America, will follow many of the same migration routes to the same pools.
Once breeding begins, some vernal pools will host a few dozen to several hundred salamanders, and handfuls to many thousand wood frogs. Large pools might contain 5,000 salamanders and hundreds of thousands of frogs. Males tend to migrate first, with females following.
Jackson cautions homeowners with vernal pools in their yards to keep the areas as natural as possible. As for watching or even catching the animals, Jackson encourages it.
"Salamanders and frogs can be handled, but carefully," he cautions. "They''ll do alright for a few days inside a house or classroom as long as they don''t get too hot, but then they should be returned to the pool."
NOTE: According to today''s weather forecasts, conditions expected Thursday night, March 16, could be favorable for migrations in the Connecticut Valley of western Massachusetts, eastern Massachusetts, southern New Hamsphire, Connecticut and Rhode Island. In general, migrations in the Berkshire Hills, and southern Vermont occur later than the above-mentioned areas.
Scott Jackson can be reached at 413/545-4743, or at email@example.com.