Ministry of Environment
Pacific Chorus Frog
|Common Name:||Pacific Chorus Frog|
|Scientific Name:||Pseudacris regilla|
The Pacific Chorus Frog is a very appealing little frog, and quite common in B.C. They are small frogs, up to 5 centimetres long, and may be any colour from pale grey or tan to bronze or bright emerald green. Pacific Chorus Frogs have a conspicuous dark "mask" or stripe extending from the nostrils through the eye as far as the shoulder. They are often marked with dark patches or stripes on the back, and are usually pale cream underneath. Their legs are long and slender; their toes have round pads, which help the frog grip and climb, and there is very little webbing between the toes, making them look quite long. Females are slightly larger than males, a feature common to most frogs.
Other similar-appearing frogs in B.C. include the Wood Frog and the Boreal Chorus Frog. Wood Frogs have a dark mask, but may be distinguished from Pacific Chorus Frogs by their toes, which do not have pads, and their dorsolateral folds (ridges running from the eye down the back). Pacific Chorus Frogs have no dorsolateral folds. Boreal Chorus Frogs are chorus frogs as well. They resemble Pacific Chorus Frogs but have much smaller toe pads, have an eyestripe which continues along the body, and usually have three stripes on their backs. Boreal Chorus Frogs are only found in a small segment of northeastern B.C., so any chorus frog found in the southern part of the province is almost certain to be a Pacific Chorus Frog.
The Pacific Chorus Frog is quite cosmopolitan in its choice of homes. Outside the breeding season, in early spring, Pacific Chorus Frogs may be found in woodlands, meadows, pastures, and even urban areas, often quite far from the nearest body of water. City dwellers on the coast are often pleasantly surprised to find that a Pacific Chorus Frog has made itself at home in their garden or even in plant pots on a balcony. The sticky pads on their toes allow these frogs to climb about on plants with great agility, though they usually stay fairly close to the ground.
During the breeding season, the Pacific Chorus Frog makes its way to shallow wetlands where there is a lot of plant cover. Often these wetlands or ponds are temporary, drying up by midsummer; they are called "ephemeral" wetlands. By using these wetlands for breeding, the Pacific Chorus Frog can avoid predatory fish and amphibians, such as Bullfrogs, which require permanent water bodies.
Early in the spring, Pacific Chorus Frogs begin to breed. Males make their way to the breeding ponds and call in unison to attract females. The choruses can be startlingly loud considering the size of the frog! The breeding call of the male is a two-syllable krek-ek, instead of the one-syllable c-r-r-ick heard the rest of the year. After mating, the females lay small clusters of eggs, attaching them to bits of vegetation in quiet, shallow water. The egg clusters are irregular in shape and may contain 10 to 70 eggs. The embryos develop rapidly, hatching two or three weeks after the eggs are laid, and the tadpoles metamorphose in approximately two months. Newly metamorphosed Pacific Chorus Frogs may be only one centimetre long! The young frogs mature quickly and may be ready to breed the year following transformation.
Adult Pacific Chorus Frogs eat spiders and a wide variety of insects, which they hunt while climbing about on plants. Tadpoles graze on algae and detritus. In turn, chorus frogs are preyed on by snakes, Bullfrogs, and many birds and mammals, and tadpoles are eaten by larger frogs and fish.
In British Columbia, the Pacific Chorus Frog is found in the southern part of the mainland and on Vancouver Island. It has been introduced to Haida Gwaii (Queen Charlotte Islands). Pacific Chorus Frogs are found southward along the U.S. west coast as far as Mexico, but are not found east of the Rocky Mountains.
Pacific Chorus Frogs can be heard calling throughout the year, especially during rainstorms, and the spring mating choruses are impossible to miss. It's very difficult to spot these little fellows, though, since they will cease calling if they feel threatened.
The Pacific Chorus Frog is quite abundant in B.C. and can use a variety of habitats, so it is not considered to be of conservation concern. This species is on the provincial Yellow List of species managed at the ecosystem level. Populations may decline in the future, however, if the loss of wetlands continues. Pacific Chorus Frogs are protected under the British Columbia Wildlife Act.
Even though Pacific Chorus Frogs are doing well in B.C., loss of wetland habitats can mean loss of local populations of these tiny frogs. Learn about wetlands and how important they are to our environment.
Take part in B.C. Frogwatch and let us know when and where you hear chorus frogs (and other amphibians) begin their spring chorus. Since the time when frogs begin to call can depend on the weather, scientists think that keeping track of this information may help us learn more about climate change. Environment Canada's EMAN program (the Ecological Monitoring and Assessment Network) coordinates the national Frogwatch program, as well as other monitoring programs.
- The Pacific Chorus Frog can change colour rapidly from light to dark, possibly in response to changes in temperature and humidity
- The distinctive call of the Pacific Chorus Frog (especially the mating choruses) is widely used in films for a "tropical" background. Cartoon frogs are often given a Pacific Chorus Frog voice as well!
- Pacific Chorus Frog can throw their voices to some extent, making it quite difficult to close in on a frog by following its call.
Photo © Wally Edwards. No reproduction or distribution without permission.