Watch this video with sound! Have you been hearing this sound? It is the hearty, resonating trill of the gray tree frog, which you will most likely hear during the late spring and summer months, especially on warm humid days and nights. Many people unknowingly mistake the frog's loud call for that of a bird, similar to how the call of a wood frog is often mistaken for feeding ducks. The gray tree frog is a true master of camouflage, so it is more often heard than seen. Thanks to Carl Lovisolo fo