Listen to the Sounds of Tree Frogs Across America

Tree frogs are a beloved part of the natural soundscape especially on warm spring and summer nights. Their calls resonate through wetlands forests, and even suburban backyards across the United States. Learning to identify tree frogs by their unique sounds can open up a new world of nature awareness and appreciation.

There are 32 species of tree frogs found in the contiguous United States. From the high-pitched “peep” of the Spring Peeper to the duck-like quacking of the Wood Frog, each species has distinctive vocalizations used for attracting mates, establishing territories, and signaling alarm Understanding the purpose and meaning behind these froggy sounds provides insight into their secret, nocturnal lives

How Tree Frogs Produce Sound

Tree frogs have a specialized vocal apparatus that allows them to generate their signature calls. Air passes from the lungs through the larynx and into vocal sacs located under the mouth. The larynx contains two vocal cords made of soft tissue that can be tightened and loosened to modulate pitch and volume.

When calling, circular muscles surrounding the vocal sacs contract, pushing air through the larynx. This causes the vocal cords to vibrate rapidly, producing sound The resonating vocal sacs amplify the sound before it exits through the mouth. Some species have larger vocal sacs than others, allowing them to belt out louder calls that can be heard from farther away.

Reasons for Calling

Tree frogs use vocalizations for several important reasons:

Attracting Mates

• The primary reason male tree frogs call is to attract female mates. Their breeding calls tend to be melodic and repetitive, allowing females to locate potential partners.

Marking Territory

• Males also call to mark and defend their territories from rival males. These territorial calls often sound more aggressive than mating calls.

Signaling Distress

• Tree frogs produce alarm calls when threatened by predators. These distress calls can help startle predators and alert other frogs to danger.

Communicating Location

• Female tree frogs may use less melodic calls to help males find them once a mating call has attracted potential suitors.

When and Where to Listen for Tree Frogs

Tree frogs are generally nocturnal, so nighttime and early morning are the best times to hear them. However, some species also call during the day. The breeding season usually lasts from spring through summer, but can start as early as late winter in some areas.

Wet, wooded habitats like marshes, swamps, ponds, and streams provide ideal calling spots. However, tree frogs will utilize any water source, so don’t be surprised if you hear them in backyard pools, roadside ditches, or gutters after a rainstorm.

Distinctive Sounds of Tree Frog Species

Here are some of the most common tree frog species found across the United States and their identifiable mating calls:

• Spring Peeper – High-pitched “peep” sounding like a whistle, often in choruses that resemble jingling bells.

• American Toad – Long musical trill lasting 5-30 seconds, slightly different pitch from each male.

• Green Tree Frog – Abrupt “clunk” sound, like plucking a banjo. Often given in groups dropping in pitch.

• Gray Tree Frog – Melodic trill lasting ~0.5 seconds, repeated every few seconds.

• Cope’s Gray Tree Frog – Similar to Gray Tree Frog but faster trill rate.

• Wood Frog – Soft quacking sound, like a duck. Choruses can sound like flock of ducks.

• Cuban Tree Frog – Very high-pitched, machine gun-like call.

• Pacific Tree Frog – Makes recognizable “ribbit” mating call.

• Bullfrog – Deep resonant “jug-o-rum” call, sometimes drawn out.

• Southern Leopard Frog – Snoring call followed by soft grunts.

Telling Tree Frogs Apart by Sound Alone

With practice, seasoned nature lovers can identify tree frog species simply by their calls. However, many calls are similar or variable depending on temperature and the individual frog. Here are some tips for deciphering those challenging frog choruses:

• Listen for similarities to familiar sounds like bells, ducks, whistles, etc. This can provide clues to the species.

• Note characteristics like pitch (high or low), pace (fast or slow), and tone (musical, harsh, soft).

• Listen for how long each call lasts and the intervals between calls.

• Pick out distinct differences between simultaneous calls to detect multiple species.

• Remember some frogs have a wider range of sounds unlike the stereotypical advertisement call.

Enjoy Nature’s Symphony

Being able to distinguish the one-of-a-kind sounds of tree frogs provides a portal into appreciating nature at its finest. As spring and summer approach, take time to sit near a wetland habitat at night and listen to who is singing. See if you can put names to the voices and piece together the complex ecology happening in frog-speak all around you. Opening our ears to nature’s music is a simple pleasure that tunes us in to the wonders of the natural world.