Male frogs have tremendously diverse vocalizations, and their sounds can mean different things depending on the listener. Female frogs might assess the quality of a male through the nuances of his call. Male frogs might decide whether or not to fight based on a the sound of another male's call. Predators might think the song signals a tasty treat. People might interpret the songs as a sign of the change of seasons.
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American Toads (Bufo americanus A.K.A. Anaxyrus americanus) have a high pitched trill that can last from six to twelve or more seconds. Its long duration helps distinguish it from the individual "Peeps!" of the Spring Peeper, or the short trill of the Gray Treefrog.
American Toad 2015 Playlist: four short videos of American Toad breeding behavior. The first video shows two toads calling to each other. The second video shows a toad calling next to a spring peeper. The third video shows some male toads trying to break apart two amplexed pairs of toads. The fourth video shows a group of four males battling each other to mate with a single female toad.
American Toad 2016 Playlist: several short videos of American Toads in northeast Ohio. The first set of videos show individual calling male toads before females arrive at the pond. In addition to the long trill of the toads, you can hear the Spring Peepers calling too.
Spring Peepers (Pseudacris crucifer) have a distinctive call that consists of a single high-pitched "Peep!". Individual Spring Peepers can make these peeps in quick succession. When hundreds of Spring Peepers are gathered together on a warm rainy night during the breeding season, the sound can be deafening!
The Spring Peepers' "Peep!" is called an advertisement call because it is used to attract females. A different sound, called an "encounter" call, is used to chase off other males. The encounter call sounds like a short trill. The peeper in this video starts with the peeping advertisement call. But four seconds into the video, a trilling "encounter" call is heard off-camera. The peeper continues to make a few more advertisement peeps, then becomes fed-up 16 seconds into the video, and starts making his own trilling "encounter" call.
Spring Peepers are cute little frogs, but the males will also aggressively battle with other males. In this video, a male spring repeatedly makes a trilling "encounter" call as it walks up a branch to chase off two other peepers.
Western Chorus Frogs (Pseudacris triseriata) are found over much of the eastern United States, and often co-occur with Spring Peepers. Although both Spring Peepers and Western Chorus Frogs are in the same genus, their calls are quite distinct. The calls of the Western Chorus Frog sound like someone running a thumb over a comb, but much louder!
This video shows two different Western Chorus Frogs, each singing by the edge of the pond. You can hear many other Western Chorus Frogs in the background.
The video to the left shows a top-down view of a calling male pacific chorus frog. This video provides a nice visual illustration of another function of the vocal sac: to refill the lungs after calling. As you watch the video, you can see the relationship between the vocal sac and the lungs. Sound is produced as the frog forces air out of its lungs into the vocal sac. The air rushing out of the lungs passes through the vocal cords, creating the frog call. As the lungs deflate, the body appears to get smaller as the vocal sac expands. But after the frog is done calling, the air is forced from the vocal sac back into the lungs. You can see this happen as the vocal sac gets smaller and the frog's body appears to get larger as it fills with air.
2013 Gray Treefrog Playlist These three videos show different male gray treefrogs (Hyla versicolor) seen on May evening in Livingston County, Michigan. In the first video you can see a beetle larvae swim past the male. In the second video, you can see the treefrog hidden between two big spatterdock leaves. In the third video, the treefrog is boldly sitting out in the open. This large wetland was full of hundreds of calling male gray treefrogs, as you can tell from the continuous background of their calls.
2016 Gray Treefrog Playlist The first video shows a gray treefrog (Hyla versicolor) calling from the trunk of a tree. The treefrog was perched about 4 feet (1.2 meters) above the ground, with his back to the pond. In the second video, a male graytreefrog is calling from a perch on a tree limb hanging directly over a pond. In the background of some of these videos you can also hear the calls of American Toads, Spring Peepers, and Green Frogs.
Comparing Calls of Two Species of Gray Treefrog: There are two species of Gray Treefrog in North America, and they can't be told apart from their external appearance. However, you can identify them by the sound of the males' calls. This video gives examples of the difference in the calls of the two gray treefrog species. The first frog in the video is Cope's Gray Treefrog (Hyla chrysoscelis), which has a high number of trills per second. The second frog is a Gray Treefrog (Hyla versicolor), which has fewer trills per second. More information on these species can be found at Amphibia Web, Chris Harrison's Frog Blog, and Theodora Pinou's Hyla versicolor site.