Wood Frog Overview
Ask West Virginians to name their favorite sign of spring and you’re likely to get a hundred different answers, ranging anywhere from robins to ramps. It’s doubtful, though, that even one would mention a small amphibian known as the wood frog. Few people ever see one, so its obscurity is understandable. Known to herpetologists as Rana sylvatica, wood frogs spend most of the year in the forest, foraging for insects during the warm months and hibernating beneath the litter in winter. Early spring is the time to observe wood frogs. That’s when they congregate, sometimes by the thousands, in shallow, seasonal woodland ponds to breed and lay their eggs.
Trout fishermen and winter-weary canoeists stand the best chance of encountering a colony of wood frogs. Flood plain depressions inundated by the high stream flows of early spring are favored breeding sites. It’s not hard to locate breeding frogs if you’re in the right area, in fact you don’t even need to look for them. During their frenzied stay at the pools, which may last from a few days to two weeks, wood frogs reveal their location and their intentions by the continuous day and night calling of the males. The sound they produce summons to mind anything but the sounds we commonly associate with frogs. Naturalists have likened the sound to everything from the quacking of ducks to the cawing of angry crows harassing a hawk. Instead of sitting at water’s edge with inflated throat sacs as do most frogs and toads, male wood frogs sing while floating, spread eagle fashion, on the surface. To produce the odd song, the frog passes air over its vocal cords from a pair of inflated sacs located on the side of the body, just behind the head.
Congregation at the breeding pools begins with the first several consecutive nights at temperatures above freezing. February 20 marks the earliest reported date observed for breeding activity in West Virginia. Sometimes the frogs are fooled by an early thaw. Returning cold covers the breeding pond with a new layer of ice, freezing any eggs too near the surface. But the frogs simply retreat to the safety of the bottom to await more seasonable conditions. They and their eggs suspended beneath the ice appear none the worse for the interruption. Females lay between two and three thousand eggs in globular, jelly-like masses which generally hatch in a few days. The tadpoles grow quickly, with metamorphosis completed by early June. At this time the young frogs leave the shrinking pools for life in the woods.
Wood frogs are small frogs ranging in length from 1.5 to 3 inches, measured from snout to vent. They are unspotted with dorsal coloration varying from light pink to tan, gray, and even nearly black. The best field mark is the black mask which extends across the cheek and through the eye. This band is always visible, even on darkly colored individuals. Wood frogs are more graceful in appearance than most frogs, delicately built and well adapted to life on land.
The wood frog is a northern creature, inhabiting forests from New England and the Great Lakes, northwest across boreal Canada as far as central Alaska. The range of the species reaches its southern limits in the Appalachian Mountains, occurring throughout West Virginia and as far south as northern Georgia.
Sometimes spring’s arrival seems to take forever in the mountains. But there are always signs for those who know where and when to look. One of the most interesting is the wood frog. Be alert in the spring when visiting the haunts of the wood duck, the beaver and skunk cabbage, for that’s where you’ll find him. And remember, if you want to see this interesting component of the Mountain State’s fauna, keep your ears open.