Tree frog

To get from one place to another, gray tree frogs take a leap and spread out their legs and toes and glide, much like a flying squirrel.

While poking around the garden the other day I found an adorable visitor, a small frog called a gray tree frog (Hyla versicolor) resting among the brightly colored flowers.

This amazing little creature can be found in a wide range of habitats throughout the eastern half of the United States from Canada to Texas.

Tree frogs live in trees, unlike most other frogs, which are pond-, lake- and river-dwellers. But the gray part of the name can be a bit confusing because most of the time, when you see this little amphibian, it is green.

Gray tree frogs can change their color depending on the substrate where they are. If they are on a tree trunk, they are often gray in color, and if they are on green leaves, they will be green. They don’t change color as fast as a chameleon, but it’s fast enough to keep these little arboreal frogs safe and camouflaged.

In addition to turning green or gray, they also have dark mottling, or black lines, that help complete the camouflage package. Overall, they can range from nearly black to bright gray or nearly white. Interestingly, when one of these frogs dies, it turns gray.

Even with all the color changes, one thing stays the same color: They have a yellow patch on the inside of their hind legs. Normally you don’t see this until they either hop or stretch out their hind leg, then it’s obvious.

Females tend to be larger than males and have a white throat. Males are smaller and have darker throat patch. Tree frogs are smaller than most of our other frog species, ranging 1-2 inches in length.

We have a second tree frog species in eastern North America, the Cope’s gray tree frog (Hyla chrysoscelis). The two frog species are identical in appearance. The main difference is in the number of chromosomes, so that is not much help when trying to figure out which species you have in your yard.

However, the two species have different calls, so if you can hear the male call, you can tell the difference. The Cope’s gray tree frog has a faster trill shorter than the gray tree frog’s.

The rates at which both frogs call are highly temperature-dependent. At lower air temperatures, the call slows down, making them very difficult to distinguish. Breeding season is early to mid-summer, when males actively call from the trees. They can be very loud when several males gather and call.

These frogs rarely leave wooded areas but can be found in gardens and around homes. They are often attracted to insects, which are their main diet, in our gardens or to a porch light on your house that attracts insects. Many people see these frogs stuck to windows as they try to catch food.

They can climb right up a glass window with their amazingly sticky toe pads. No, they don’t have suction cups on their toes; rather tiny glands produce a sticky mucus that allows them to stick to just about any surface. In addition, their toe tips are more flexible than other frogs’, which helps them grab onto tree branches or other thin objects and stick like glue.

To get from one place to another, tree frogs take a leap and spread out their legs and toes and glide much like a flying squirrel. They stop by snagging any surface with their toes.

Of course, one of the most amazing aspects of this frog is its ability to overwinter. In fall they seek shelter on the ground under as much leaf litter as they can find. As the temperature drops below freezing, so does the frog. They remain frozen all winter and will thaw in spring and miraculously come back to life.

Look in your own garden to see one of these amazing amphibians.

Until next time …

Stan Tekiela is an author, Eden Prairie city naturalist and wildlife photographer who lives in Victoria and travels the United States to study and photograph wildlife. He can be followed on Facebook and Twitter. He can be contacted via naturesmart.com.

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