5 Types of Tree Frogs Found in Illinois! (ID Guide)
“What kind of tree frogs can you find in Illinois?“
Tree Frogs are interesting animals that have adapted to all sorts of habitat niches. And while they are common, they are MUCH harder to find than your “typical” frogs that live in lakes and ponds. For example, a tree frog could literally be right next to your head, but it may be concealed on the other side of a leaf or camouflaged perfectly to its environment.
So what exactly qualifies as a tree frog?
For the sake of this article, I have included members of Hylidae, which is the family that encompasses all tree frogs in Illinois. But don’t let the name “tree frog” fool you, as species from this family are not always arboreal but can be terrestrial and semi-aquatic too!
Since tree frogs can be hard to observe, I have tried to include audio samples for each species. Listening is sometimes the BEST (or only) way to locate each species. 🙂
5 Types of Tree Frogs in Illinois:
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#1. Spring Peeper
- Pseudacris crucifer
- Adults are small and range from 1 to 1.5 inches long.
- They’re typically tan or brown, with the females being lighter in color.
- Both males and females usually feature a dark cross or ‘X’ on their back.
These tiny tree frogs can be found all over Illinois.
You’ll typically find Spring Peepers on the forest floor among the leaves. However, they do have large toe pads that they use for climbing trees.
Spring Peeper Range Map
You can find them in ponds and small bodies of water in the spring, where they breed and lay eggs. After hatching, the young tree frogs remain in the tadpole stage for about three months before leaving the water.
Spring Peepers get their name from their distinctive spring chorus. They’re thought to sound like the “peep” of baby chickens. You are most likely to hear them in early spring! LISTEN BELOW!
Their calls are very distinctive, and these tree frogs are easy to identify by sound.
#2. Gray Tree Frog
- Dryophytes versicolor
- Adult body lengths range from 1.5 to 2 inches.
- Mottled gray, green, and brown coloring. Look for a whitish spot beneath each eye.
- Bumpy skin, short snouts, and bright orange on the undersides of their legs.
This incredible tree frog can slowly change colors to match what it’s sitting on to camouflage itself. And you thought chameleons were the only animal that can change colors! They vary from gray to green or brown. It’s common for their back to display a mottled coloring, much like lichen.
Gray Tree Frogs are ubiquitous throughout Illinois. You’ll spot them in a wide variety of wooded habitats, from backyards to forests to swamps.
Gray Tree Frog Range Map
They stick to the treetops until it’s time to breed. Gray Tree Frogs prefer to mate and lay eggs in woodland ponds without fish. They’ll also use swamps and garden water features.
Gray Tree Frogs are easier to hear than to see.
Listen for a high trill that lasts about 1 second, commonly heard in spring and summer.
*Gray Tree Frogs are essentially identical to Cope’s Gray Tree Frogs. The only way to tell the difference is to listen to their breeding calls. You can learn more by visiting this site.*
#3. Blanchard’s Cricket Frog
- Acris blanchardi
- Adults range from 0.6 to 1.5 inches long.
- Warty skin is typically tan, brown, olive green, or gray with darker banding on the legs.
- Dark triangular mark between the eyes.
These tree frogs can be found in or near permanent bodies of water in Illinois, including bogs, lakes, ponds, marshes, and slow-moving rivers and streams. They can also sometimes be spotted in temporary bodies of water such as flooded fields and drainage ditches as long as there is a permanent water source nearby.
Blanchard’s Cricket Frog Range Map
Interestingly, although they are in the “tree frog” family, Blanchard’s Cricket Frogs spend most of their time on the ground and in the water.
Unfortunately, they are declining in parts of their range and are considered threatened. They face habitat loss, chemical contamination, and competition for resources. Another pressure these tree frogs face is their short life span, as the average individual only lives one year.
Males make unique, repetitive, metallic breeding calls.
The calls are thought to sound like two pebbles or marbles being clicked together.
#4. American Green Tree Frog
- Dryophytes cinereus
- Adults can grow up to 2.5 inches long and have smooth skin.
- Yellowish-green to lime green with pale yellow or white undersides.
- White stripes down their sides sometimes have black borders.
Even though they are common in their range, Green Tree Frogs can be hard to find since they spend most of their lives high in trees.
American Green Tree Frog Range Map
During mating season, they visit ponds, lakes, marshes, and streams to breed and lay eggs. They prefer bodies of water with a lot of vegetation. They also can change color based on light and temperature.
Their breeding call is a repeated, abrupt, nasal “bark.“ Sound is typically the best way to locate these tree frogs in Illinois.
Green Tree Frogs are often kept as pets. They are popular because of their attractive appearance, size, and how easy it is to take care of them. For example, they don’t require artificial heating like most amphibians. But being nocturnal, it’s unlikely you will see them moving around much, so they are probably not the most exciting pets!
#5. Bird-voiced Tree Frog
- Dryophytes avivoca
- Small tree frog that grows up to 2 inches long.
- Normally pale grey or brown, but it can also be shades of pale green.
- Look for a dark cross-shape on their back and darker limbs.
Bird-voiced Tree Frogs are found in Illinois in swampy forests, marshes, and wetlands. They look very similar to the larger Gray Tree Frog, so be careful when identifying.
Bird-voiced Tree Frog Range Map
These nocturnal tree frogs rarely leave the trees, except on rainy nights to breed. Females deposit their eggs into shallow pools and then leave to head back upwards. Tadpoles take about a month to metamorphize into adults, who then disperse into the forest.
Another way to correctly identify this species is to listen for them. Their “wit-wit-wit” sound is distinctive. While it’s mainly heard at night, don’t be surprised to hear a few males calling during daylight hours.
As you can probably guess from their name, many people think they sound like a bird!
Do you need additional help identifying tree frogs?
Try this field guide!
Which of these tree frogs have you seen in Illinois?
Leave a comment below!