There are two species of tree frogs in southeast Michigan; eastern gray tree frogs and Cope's gray tree frogs. Visually there is no way to tell the two apart and the calls can sound very similar depending on weather conditions. Both species have the ability to change color and range from gray to bright green, depending on the background.
Gray tree frogs are found in brushy habitats in immature, deciduous woodlands. For breeding, they do not use temporary ponds. Outside of the breeding season, they are often heard calling from trees. Their round sticky toe pads enable them to climb well and they will often stick on windows or walls adjacent to porch lights and catch insects. Gray tree frogs are small to mid size frogs, ranging from 1.25 to 2.4 inches long.
The call of the eastern gray tree frog is a musical trill, beginning around May through the first of June.