Boreal Chorus Frog (Pseudacris maculata)

Description
Boreal Chorus Frog

Size

  • Alberta's smallest amphibian, the boreal chorus frog grows to only 20 to 40 millimetres (0.8 to 1.6 inches) long.

Appearance

  • The boreal chorus frog is also known as the striped chorus frog because of the three dark, sometimes broken, stripes on its back.
  • There is a stripe through the eye and along the side.
  • Background colour varies from grey to brown to green, while the belly is generally yellow-white to light green.
  • Skin is somewhat granular in texture.
  • In contrast to true frogs, the boreal chorus frog lacks dorsolateral folds and has little webbing between its toes on the hind feet.

Voice/call

  • Call is similar to the sound produced by running your fingernail along the teeth of a comb.
Distribution
Boreal frog distribution in Alberta
  • The boreal chorus frog has the widest distribution of any amphibian in the province.
  • Historically, these frogs have been found virtually everywhere in Alberta except for alpine environments.
  • Presently, boreal chorus frogs are excluded from areas where pesticides are heavily used.
  • Outside Alberta, the boreal chorus frog is found all across the prairies and into the Northwest Territories.
Natural History

Habitat

  • Boreal chorus frogs inhabit sloughs, woodlands, and even open meadows if there is sufficient vegetation to provide cover and moisture.
  • Despite being a member of the tree frog family, the boreal chorus frog is a poor climber and is rarely found higher than the branches of a low shrub.
  • Boreal chorus frogs are at their highest densities during the breeding season. In the spring, adults will congregate at breeding ponds and begin calling.

Food

  • The boreal chorus frog eats a variety of invertebrates including snails and insects.

When active

  • The boreal chorus frog is active from spring until fall.
Reproduction and Growth
Life Stage Apr May Jun Jul Aug Sep
Breeding Breeding Bar: April 15 to June 15
Eggs Hatch Eggs Hatch Bar: April 22 to June 22
Transformation Transformation Bar: June 22 to August 22

Breeding behavior

  • Breeding begins as soon as most of the snow has melted. This breeding can be as early as April in some parts of the province.

  • Males congregate in small ponds or temporary pools and begin calling. The calling can occur during both the night and day.

  • Eggs are laid in small masses of jelly attached to sticks or other vegetation in shallow water.

  • Number of eggs laid is highly variable, from 150 to 1500.

  • Each egg is about one millimetre (0.04 inches) in diameter and will hatch in 10 to 14 days.

Appearance of young

  • Boreal chorus frog tadpoles are quite small when hatched, about four to seven millimetres (0.16 to 0.28 inches), but grow to about 30 millimetres (1.18 inches) before transforming into juvenile frogs in about two months time.

  • The tadpoles are dark with a silvery underside flecked with gold.

Growth process

  • Newly transformed frogs are quite tiny, only 7 to 12 millimetres (0.28 to 0.47 inches) long after they have absorbed their tails.

  • The new frogs will reach maturity and breed the next summer except in the northern half of the province, where they generally do not breed until their third summer.

Conservation and Management

Status

Classified as Secure in the current Status of Alberta Wildlife report and is not considered to be at risk. See:

Issues

Populations are healthy and widespread.

Current management

  • Amphibian Monitoring in Alberta
    The boreal chorus frog is being monitored under the Alberta Volunteer Amphibian Monitoring Program (AVAMP) and the Researching Amphibian Numbers in Alberta (RANA) program.
Similar Species
  • Wood frog
    The wood frog also has a stripe through the eye, but it is larger and has prominent dorsolateral folds (ridges) on its back.

Related links

  • Amphibians
    Learn about Alberta’s amphibians, their biology and how to identify various species. Also learn about the global decline of amphibian species, and efforts made to monitor and conserve them.
  • Frogs
    Find out about the common traits of frogs, and about the different frog species found in Alberta.

 

Page Information

Updated: Apr 23, 2018