Western chorus frog
Pseudacris triseriata
Western chorus frogs are widely distributed throughout Ohio. They become rare in northeastern Ohio east of Cleveland. Western chorus frogs are small frogs with poorly developed toe discs; they seldom exceed 32 mm in total length. In contrast to the mountain chorus frog that prefers wooded hills and valleys, the western chorus frog prefers open fields and prairies with dense vegetation.
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| Fig. 13. Western chorus frog |
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The western chorus frog is an attractive light brown to dark brown in color with three dark brown stripes on the back as well as a lateral stripe on each flank (Fig. 13). Both species of chorus frogs have a black facial mask, a dark triangle positioned between the eyes, and a white line on the upper lip. Females average slightly larger than males and have white throats whereas males have a yellowish wash mottled with dusky over the vocal sac during the breeding season.
• The western chorus frog has a black facial mask, a white line on the upper lip, and a dark triangle between the eyes.
• In addition, there are three dark stripes coursing down the brown back and a lateral stripe on each flank extending from the snout nearly to the hind leg.
Western chorus frogs emerge from hibernation on land near breeding areas very early in late winter or early spring, and where they occur in the same geographical area, they begin calling one to several days before spring peepers and woodfrogs. The breeding season extends from late February or late March to late April or early May. During the height of the breeding season the frogs may call day and night from vegetation in and beside shallow temporary pools and ditches.
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| Fig. 12. Eggs of the western chorus frog |
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Eggs are laid in loosely packed, submerged clusters of 20-75, usually attached to vegetation (Fig. 12). Each female may lay several masses totaling 500-1500 eggs. The eggs have a diameter of 1.5 mm but swell to 4-7 mm when the protective layers become hydrated. Development from the egg to transformation requires 60-80 days depending upon water temperature, and transformation into froglets about 11 mm in length takes place in June or July when tadpoles have reached a length of 26-32 mm.
Eggs of western chorus frogs are laid in clusters of 20-75 attached to vegetation below the surface of the water. The elongated, cylindrical egg mass measures about 15-20 mm wide by 25-40 mm in length.
Each egg measures about 1.5 mm in diameter when laid but swells to 4-7 mm when hydrated.
The call is a slow trill not unlike the sound of your finger running over the finer teeth of a comb, rising in frequency throughout its duration (Fig. 14).
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Fig. 14. Call of the western chorus frog |
Call of the western chorus frog (18 seconds, 141 KB)
Excerpt (5 seconds, 45 KB)
A chorus of western chorus frogs (43 seconds, 338 KB)
• The call of the western chorus frog is a slow trill increasing in frequency throughout the call; it sounds similar to the sound produced by running your finger over the finer teeth of a comb.
• The dominant frequency of the call in the spectrogram is about 2600 Hz, and the call duration is 0.5 seconds.
• There is a constant din of spring peepers calling faintly in the background.