Western Chorus Frog {Pseudacris triseriatd) 



Description: Adults are very small (0.75-1.5") and have tiny, almost unnoticeable toe pads. 



They have a dark line extending from the snout through the eye to the groin. Basic coloration 

 is quite variable with the background color being green, brown, gray, or reddish. Typically 

 3-5 dark longitudinal stripes are present on the head and back which may be broken up into 

 spots on some individuals. 



Eggs and Tadpoles: Eggs are laid in small clusters of 10-100, usually less than 1" across and 

 attached to submerged vegetation (Wheeler and Wheeler 1966, Baxter and Stone 1985). 

 Individual eggs are about 1 mm in diameter. Tadpoles are brown/bronze and the eyes are 

 located on the sides of the head. 



Similar species: Pacific Chorus Frogs {Pseudacris regilla) have obvious toe pads and an eye 

 stripe ending at the shoulder and are not present near the CNF. Recently metamorphosed 

 Ranid frogs could be confused with this species, but the coloration differs and the tiny toe 

 pads are lacking. 



Habitat and Habits: Western Chorus Frogs are regularly found in the water only during the 

 breeding period in spring. Their presence is obvious during this time due to their call which 

 is given frequently at night and sporadically throughout the day. Calls were rarely heard 

 during the surveys of the Sioux-CNF; it seems apparent that breeding had finished by the 

 ■ time we surveyed in mid-June. Following breeding, these frogs move into adjacent uplands 

 and are rarely seen. In eastern Montana, they breed in temporary ponds and small lakes 

 surrounded by prairie; in some locations in Montana they are also found in open forested 

 habitats. Small to mid-sized tadpoles were present at three sites during our mid-June survey, 

 and had apparently metamorphosed by the September survey (Appendix 2,3). Eggs hatch in 

 about 2 weeks and tadpoles are about 2 months old at metamorphosis (Wheeler and Wheeler 

 1966. Nussbaume/a/. 1983). 



Surveying: Adults are easily surveyed for, using their calls for identification during the breeding 

 season in the spring and early summer. During the breeding season, adults may also be seen 

 in the water, but their small size and habit of freezing or diving when disturbed makes 

 observation difficult; night surveys may be more productive. Egg masses are difficult to 

 find. Tadpoles may be seen in ponds during the day and can be sampled with a dipnet. 



Status: Common throughout the prairies of eastern Montana. Probably common throughout the 

 Sioux-CNF; we recorded them from the North Cave Hills, South Cave Hills, and Long Pines 

 in South Dakota. Historic records exist from Montana in the Long Pines and Ekalaka Hills 

 (Appendix 4) and the East Short Pine Hills (Visher 1914). 



Montana Natural Heritage Program rank: G5 S5. 



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