General Adult Description: The Boreal Chorus Frog is a small frog that averages just over 1 inch (2.5 cm) in length. Dorsal coloration can be varying shades of tan or brown as a background typically with three stripes running down the back. It is not uncommon to find individuals with these stripes broken, but often the resulting blotches occur in a line. Additionally, a dark stripe occurs through the eyes and along the lateral sides of the body. Ventral coloration is typically white. Because this species is primarily arboreal, webbing between the toes is diminished and a small circular toe pad is present on the tips of toes. Adult males can be distinguished from females by the presence of a dark colored throat (females have a light colored throat), though this may fade outside of the breeding season.
General Larval Description: Larval Boreal Chorus Frogs are small in size, but still can be larger than most true toad tadpoles. Tadpoles are dark in coloration, have a high tail fin, and lateral eyes. The best way to identify these tadpoles is from their bicolored tail musculature: the dorsal portion of the tail muscle is dark and the ventral portion of the tail muscle is light.
Call Description: The Boreal Chorus Frog can have a remarkably loud call given their small size. The breeding call is a series of metallic clicks that rise in pitch, often compared to the sound of running fingers along the teeth of a rigid comb. You can listen to a chorus of Boreal Chorus Frogs calling here: Pseudacris maculata (SD: Minnehaha Co.)
Behavior: Like most frogs, this species is primarily nocturnal; however, breeding males may continue to call throughout the day. During winter, individuals bury into leaf litter and shallow organic material. Because these areas will still reach freezing temperatures, the Boreal Chorus Frog has the capacity to tolerate portions of their body freezing solid. As spring temperatures warm, individuals thaw and adults move to wetland habitats to reproduce.
Reproduction: Boreal Chorus Frogs are the one of the earliest breeding frogs in South Dakota (along with Wood Frogs) and as such, ice and snow may still be present. Breeding activity begins as early as March and continues into late May. Calling has even been heard as late as October in South Dakota (Blais et al. 2016. Herpetol. Rev. 46:416–417). Females lay series of small egg masses attached to submerged vegetation. Eggs quickly hatch (often before other species begin to breed) and tadpoles complete metamorphosis often by late June.
Habitat: Because of their statewide distribution, Boreal Chorus Frogs can be found in almost any wet area, from temporary roadside ditches to large, permanent wetlands and river backwaters. Outside of breeding season, this species can be difficult to detect as adults move to upland habitats.
Species Range: This species has a large range across most of the central United States, north into Canada (Saskatchewan, Alberta, Manitoba, Québec), east into the Great Lakes region, south to parts of New Mexico and Arizona, and west into much of the Rocky Mountains.
South Dakota Range: The Boreal Chorus Frog has one of the largest distributions across the state and can be found statewide.
South Dakota Status: This species is not listed by South Dakota Game, Fish and Parks.
Account written by Drew R. Davis and Trevor G. Bertsch