The Gray Treefrog (Hyla versicolor) is common to the eastern United States. However, it is not commonly seen for three reasons.
First, as its common name suggests, it is a tree frog. In fact, it spends almost its entire life high in treetops, only returning to water in the spring to breed.
Second, as it Latin name suggests, versicolor, it can change its color from gray to green depending on the color of the material upon which it rests. They are amazing at blending into their background.
Finally, they are strictly nocturnal.
While they are hard to see, they are easy to hear. Only the male sings. The call is a short, high repeated trill heard from May to July. As they are mostly solitary frogs (they do not form large groups or sing in choruses), it may appear as if males are calling each other from different parts of the forest.
