Gray Treefrog (Hyla versicolor)

Cope's Gray Treefrog (Hyla chrysoscelis)

~ Travis Wilcoxen

Identification tips: The Gray Treefrog and Cope's Gray Treefrog look identical. Both of these frogs have green or gray colors on their backs with dark blotches in patterns that hide them when they rest on tree bark. These frogs have bright white bellies and yellow or orange markings on their inner thighs. The Gray Treefrog and Cope's Gray Treefrog have pads on the tips of their toes that are much wider than the rest of the toe, which allow them to cling to vertical surfaces (trees, windows, etc.). Male Gray Treefrogs and Cope's Gray Treefrogs emit a hearty, loud trill, particularly during the spring and summer. The only way to tell these two species apart (without analyzing their genetics) is by their calls, as the call of the Cope's Gray Treefrog is a much faster trill than the call of the Gray Treefrog, although the pitch and volume are often the same. To hear the Gray Treefrog call, click here. To hear Cope's Gray Treefrog call, click here.

No other frogs in Woodford County have the noticeable toepads that these frogs possess.

Natural history: Cope's Gray Treefrog and the Gray Treefrog spend the day high in the upper branches of trees, and descend at night to feed. They can be found in almost any wooded area throughout the state where there is a permanent water source nearby. Near Lake Eureka these frogs can be heard calling at night from trees near the lake and around the edges of Davidson Woods, but are likely to be seen in a tree only if spotted with a flashlight. The people who live around Lake Eureka may occasionally find one of these treefrogs sticking to a window or house siding near a porch light at night. These frogs could also be found near the shores of Lake Eureka during a warm, rainy night in spring.

Gray Treefrogs and Cope's Gray Treefrogs emerge in early April after overwintering under rocks or logs in the woods. Females lay jelly-like egg masses in the water attached to plants under the water. These frogs eat a variety of small insects and spiders. Birds of prey that are active at night and snakes are common predators of these treefrogs. These frogs have an amazing ability to change color, and are often encountered with a color that is in transition from green to gray. In less than one hour, Gray Treefrogs or Cope's Gray Treefrogs can completely change their back color as a result of a temperature change, humidity change, or change of object of attachment (tree bark or house siding or a window, etc.)

For additional information please visit the Illinois Natural History Survey site for the Gray Treefrog complex.

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