Walker Nature Center
A look inside • Calendar of Events 4 • Kids’ Corner 6 • Winter Bird Count Results 7
Nature Notes By Sharon Gurtz
March
• Maple trees have red blooms. • Red-shouldered Hawks are mating. • First squirrel babies of the year are born. • Spring Peepers and Wood Frogs are calling.
April
• Eastern Bluebirds are building nests. • Spicebush and Forsythia shrubs bloom. • Turtles begin sunning on logs at the lakes. • Virginia Bluebells, Trillium and Jack-in-the-Pulpit bloom.
May
• Barred Owl babies are active. • Wild Geranium, Foamflower and Wild Columbine bloom. • Spring Azure and Tiger Swallowtail butterflies are in flight. • Garter Snakes and Copperheads emerge from their winter hideouts.
Branching Out Are Those Frogs Quacking? By Ken Rosenthal
Take a twilight stroll in the forest in early spring, and you may be surprised to hear the sound of ducks. As you get closer, you may be surprised again to find that the quacking is actually coming from frogs. Male Wood Frogs make a quacking sound to attract mates to vernal pools. Their odd call is only one of their interesting attributes.
Frogsicles
Wood Frogs spend most of their time in the forest, hiding under leaf litter during the day and hunting for food at night. Unable to dig very deep, they hibernate during winter months under the leaves on the forest floor. Reston winters produce freezing temperatures, which would be fatal to most frogs, and leaf litter provides little protection from the cold. So how do Wood Frogs survive?
More than 60% of the frog’s body can freeze, with ice crystals forming under the skin, in the bladder and in the body cavity. When frozen, the frog stops breathing and has no heartbeat. A frozen frog appears dead. But once temperatures get above freezing, it will thaw. Within six hours, frogs are ready to return to normal activity. In spring, that means mating.
Thanks to special cryoprotective compounds in their blood, Wood Frogs beat the cold by safely freezing and thawing with their surroundings. Urea and glucose work to limit the amount of ice that forms in their bodies and reduce shrinkage of their cells.
Spring 14 Volume Sixteen