The Bird-voiced Treefrog (Hyla avivoca) is a small species reaching on average a size of about 1.75 inches (record size is about 2 inches or 52 mm). Females average larger than males. The Bird-voiced Treefrog is a highly arboreal species. It climbs high into trees in hardwood floodplain swamps of the southern Atlantic Coastal Plain, the Gulf Coast, and along the lower Red and Mississippi River drainages. This species is gray, brown, or greenish in color, with a white square below each eye, and often one or more large dark blotches on the back. It bears strong resemblance to the Gray Treefrog (Hyla versicolor) and Cope's Gray Treefrog (Hyla chrysoscelis). Both Gray Treefrogs have ranges that overlap that of the Bird-voiced Treefrog, which differs from them as follows:

1. Adult Bird-voiced Treefrogs are smaller in average size.
2. The color on the concealed surfaces of the thigh and groin ranges from light green to white (yellow to golden orange in the gray treefrogs). See photos of jumping Bird-voiced Treefrog (below left) and Gray Treefrog (below right) for comparison.
3. There is a divided pustule at the base of the fourth fingers on each hand (undivided in the Gray Treefrogs).
4. The call is a series of piping, bird-like whistles issued in rapid succession (it is a musical trill in H. versicolor, and a buzzing trill in H. chrysoscelis).
5. It prefers deep, wooded swamps, where Gray Treefrogs seldom occur.