Boreal Chorus Frog

Overview:

Scientific Name: Pseudacris maculata

Size: 0.7 – 1.5” (adult size)

Status: Locally abundant, has experienced some decline over the past decade

Michigan State Status: Special Concern

MDNR Wildlife Action Plan Status: Species of Greatest Conservation Need

Habitat:

Prefers marshes, meadows, swales, and other open habitats. May occur in wet woods and wooded swamps. Found beneath logs, rocks, and leaf litter. Found in the western edges of the Upper Peninsula.

Conservation:

Although the boreal chorus frog encompasses a relatively large range, their distribution in Michigan is limited to the inland island of Isle Royale as well as along the surrounding rocky shoreline/bedrock lakeshore of Lake Superior. The recent increased development of shorelines in the area is making it increasingly difficult for Boreal chorus frogs to locate suitable habitats that contain features critical to their life history requirements. Listed as a species of special concern, this habitat loss proves to be a great threat to the Boreal chorus frog’s existence on the Michigan landscape.

Best Management:

Identify and protect quality boreal chorus frog habitat containing extant populations. Breeding pools being utilized by Boreal Chorus Frogs should be documented and monitored. Maintain habitat connectivity between adjacent breeding pools and surrounding forested or open habitat. If tree harvesting is to be conducted near habitat occupied by this species, harvest during late fall to early winter. Consider implementing various tree harvesting techniques such as the shelterwood method and rotate cuts (20-70 years). Avoid clearcutting large areas and maintain woody debris, leaf litter, and understory vegetation throughout. Provide egg laying structures by submerging finely brushed trees or brushed in breeding pools.

Adult Coloration:

Brown, reddish, or tan to gray or olive body color with a white or cream stripe along the upper with bordered by a dark brown stripe running from through the eye from the nose to the groin. Usually has three stripes that run down the back that may be broken up into spots. The belly is cream or white with occasional dark spots on the throat and chest.

Adult Characteristics:

The skin is slightly bumpy but is moist. The toes are slightly expanded into pads. The hind legs are shorter resulting in locomotion more similar to a hop than a leap. Males are slightly smaller with a yellowish vocal sac that is apparent as a grey flap of skin. Call is a short, scratchy “cree-ee-ee-ee-eek” similar in sound to that of a comb being strummed with a fingernail.

Mass: 1 – 5 g

Typical Lifespan in Wild: 1 – 3 years

Breeding Interval: Once Annually

Breeding Season: May- June

Range number of Offspring: 500 – 1500 eggs

Average number of Offspring: 1000 eggs

Range time to Hatchling: 2 – 27 days (metamorphosis: 30 – 90 days)

Average age at sexual/reproductive maturity (female): 1 – 2 years

Average age at sexual/reproductive maturity (male): 1- 2 years

Diet: The boreal chorus frog preys on small invertebrates such as crickets, ants, beetles, spiders, waxwings, springtails, and midges while tadpoles primarily eat algae.

Known Predators: snakes, birds, small mammals, and other amphibians

Larvae Characteristics:

Tadpoles are rounded and gray or brown from above sometimes with a brassy mottling as they age. Tail fins are clear with dark speckling. The intestines are visible through the bronze belly. Maximum length prior to metamorphosis is 1.2”.

Species Confused With:

The Spring Peeper does not have the distinct white upper lip stripe and usually has an X-shaped mark on the back. Blanchard’s Cricket Frog has rougher skin and does not have a white lip line or dark stripes on the back. Small Wood Frogs have similar markings on the lip but their dorsolateral folds (raised ridges extending down each side of the back) differentiate themselves.