What has four legs and sounds like a duck?
If your answer is a wood frog, you are correct, and you may be familiar with the duck-like quacking sounds they make. Each spring, wood frogs (Lithobates sylvaticus) flock to local vernal pools with one goal in mind — to find the perfect mate and produce offspring. Male frogs are the ones who chorus. They emit their quacking croaks to attract females.
You’ll find wood frogs in Virginia’s mountains and throughout the Piedmont and the state’s northern coastal plain. Seeing them in the wild can be tricky, but if you know when and where to look, you will have a chance.
Contrary to logic, a good time to spot wood frogs in Fairfax County is late February and early March when winter has not quite released its icy-cold grip. This is the time the frogs gather in vernal pools and shallow ponds to breed.
Wood frogs have a special adaptation that gives them a jump on the other frog species seeking to breed in vernal pools. Wood frogs can survive freezing temperatures by producing glucose that acts like antifreeze in their blood. In winter, many wood frogs hide below leaves or under logs in forest areas near vernal pools. If they freeze, they can thaw as temperatures warm even if the pools still have an icy covering. Wood frogs are one of the first amphibians to come out of hibernation to breed, and you may find them just as snow is melting.
Vernal pools can be found in many places throughout Fairfax County. They appear in small and isolated areas that will be dry for part of the year. When full of water, vernal pools provide frogs and toads a safe place to breed and lay eggs away from predatory fish who may want to eat them.
Frogs are not the only ones taking advantage of vernal pools. In spring, vernal pools teem with life. Salamanders, insects and even small crustaceans can be found with close observation. These pools are habitats that many creatures rely on to survive.
You can help wood frogs
Many conservationists consider frogs to be the most imperiled animal group in the world. Recent reduction in their numbers is attributed largely to habitat loss and disease. Supporting areas with vernal pools and wetlands is a good way to help preserve frog populations.
Many Fairfax County parks feature wetlands and vernal pools. Parks help to conserve habitats that are vital to amphibians. At home, you can help by reducing pesticide and herbicide use. Look for natural alternatives because many wetland areas are sensitive to chemical pollution.
You can hear wood frogs on YouTube on the Park Authority’s video titled Frog Calls. The Fairfax County Park Authority offers many programs for the public on amphibians and vernal pools. Ellanor C. Lawrence Park will host Amphibians After Dark on Saturday, March 28, 2020, from 7:30 to 9 p.m.
Author Lara Dolata is a Park and Recreation Specialist at Ellanor C. Lawrence Park in Chantilly, Va.