On March 23, 2015 we heard the brief call of several wood frogs signaling their reawakening from a long winter nap. Wood frogs don't just nap but enter into a form of suspended animation where their system completely shuts down, even their hearts stop beating. As the temperatures warm they slowly awaken and begin their journey to nearby vernal pools and ponds to breed. Listen for the familiar 'cluck, cluck' sound of their calls.
The great photo of wood frog photo, shown here, is by Brian Gratwicke, made available under the Creative Commons License.