Tiny clams sometimes have been found attached to the toes of boreal chorus frogs. The frogs may serve as dispersal agents for the clams, which are restricted to waters and cannot move very far on their own. The frogs might even rarely move the clams from one body of water to another.
Photo Credit: Geoffrey A. Hammerson
Pseudacris maculata
Common Name: boreal chorus frog
Other Common Names: striped chorus frog, western chorus frog
Other Scientific Names: Pseudacris triseriata
Animal Guild: Amphibian
Class > Order > Family: Amphibia > Anura > Hylidae
What does the species look like?
Boreal chorus frogs have a dark stripe or "mask" through each eye from the snout to the groin. The upper side is variable--green, brown, reddish, or reddish and green, with green or brown stripes or spots. The hind toes are not distinctly webbed. Maximum snout-vent length is about 1.5 inches (37 mm). The throat skin of mature males is loose and yellowish or dark during breeding season. The expanded vocal sac is evenly rounded or slightly flattened. The breeding call is a stuttering "preeep" that ascends in pitch. Larvae are olive to blackish, with a tall tail fin that is strongly arched and finely stippled or squiggled with brown. When viewed from above, the eyes of larvae are at the outside margin of the head. The coiled gut is more or less visible through the pale golden belly skin. Larvae grow to a maximum total length of about 2 inches (52 mm, usually 35-38 mm). Eggs are pigmented over more than one-half of the upper surface; the pigmentation is heaviest at high elevations. Egg diameter is 0.76-1.32 mm, and is larger at higher elevations than in lowlands. Eggs are deposited in loose, irregular or elongate clusters of a few to more than 150.
Where is the species found?
States & Provinces
AB, AZ, BC, CO, IA, ID, IL, IN, KS, MB, MI, MN, MO, MT, ND, NE, NM, NT, NY, OK, ON, QC, SD, SK, UT, VT, WI, WY, YT
Distribution
Range includes large areas of Canada and the western and north-central United States from the Great Bear Lake in Canada's Northwest Territories to northern Ontario, southward to Arizona, New Mexico, northern Oklahoma, Missouri (possibly northern Arkansas), and Illinois; disjunctly also in southern Ontario, southern Quebec, northern New York, and northwestern Vermont. Elevational range extends to above 12,000 feet (3,670 meters) in Colorado and Utah.
Habitat is mostly the vicinity of quiet bodies of water and associated wetlands and meadows; sometimes these frogs cross up to a few hundred meters of upland habitat between wetlands, and they may overwinter in upland sites adjacent to wetlands; periods of inactivity may be spent in water, among thick wetland vegetation, under objects on the ground, or in rodent burrows. Chorus frogs breed in marshes, rain pools, pools formed by melting snow, bog ponds, glacial kettle ponds, beaver ponds, marshy edges of lakes and reservoirs, flooded areas, and other bodies of water with little or no current and good exposure to the sun. Both permanent and temporary waters are used (much more often the latter), and eggs commonly are laid in ponds that dry up before the tadpoles metamorphose. Eggs usually are attached to vegetation in shallow water.
General Phenology and Life History
Emergence from wintering sites typically occurs in March in lowland areas. Activity extends into September and October, and some individuals remain active into November, even after cold spells. In general, these frogs tend to be relatively inconspicuous in lowland areas in summer. Spring emergence in the mountains may not occur until May. Chorus frogs at high elevations sometimes remain active even after September snowstorms but in other places or years may disappear by mid-September even if warm weather continues. In the mountains, most activity occurs between late morning and mid-afternoon, though calling activity may extend late into the night during the breeding season. Activity in lowland areas tends to be diurnal in early spring and fall, nocturnal or crepuscular during warm spring and summer weather. In lowland areas, males usually begin calling in late March or April, usually when air temperature is above 10 C. Chorusing continues through spring and early summer. By early to late June calling may come to a temporary halt, only to begin again in June, July, or even August after heavy rains or when fields are flooded with irrigation water. In the Great Plains region of Colorado, most egg laying occurs in April, May, and June. At high elevations, breeding begins immediately after the spring thaw in late May or early June and may continue into July. Calling (but not egg laying) commonly occurs through late August at high mountain breeding sites and in adjacent meadows. Some of the males calling in August appear to be young of the year. Each female may lay several egg clusters. Hatching may occur within a few days or up to about a week after laying. Metamorphosis occurs as early as early June in lowland areas and primarily during July and August, sometimes as late as early September, in the mountains. Young usually leave the water before the tail is fully resorbed. Breeding populations at low elevations are composed only of individuals that hatched the previous year. At higher elevations males do not breed until they are about two years old, females not until three years old.
Which phenophases should I observe?
Do you see/hear...?
Activity
Adults on land More...
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Adults in water More...
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Reproduction
Vocalizing What is the intensity of vocalizing?
Single calls: There is space between calls and individuals can be counted. Overlapping calls: Calls of individuals can be distinguished but there is some overlapping of calls. Full chorus: Calls are constant and overlapping.
Mating For abundance, enter the number of individual animals observed in this phenophase.
Fresh eggs For abundance, enter the number of individual animals observed in this phenophase.
Development
Dead adults For abundance, enter the number of individual animals observed in this phenophase.
What do these phenophases look like?
There is currently no photoguide available for this species. If you'd like help us create one, use the guidance document and species template provided here . Then send it via email to education@usanpn.org when it is complete.
