Pseudacris maculata
(Boreal Chorus Frog)

also: Pseudacris triseriata maculata

Key Characteristics:

Adult Characteristics

Tadpole Characteristics

Egg Characteristics

Pointed snout

Brown dorsally and
light ventrally

Small clusters
(30-75 eggs)

Long toes with
small toe pads

Eyes extend past
margin of head

Pigmented

Three stripes (sometimes broken)

Intestines visible

      .

Limited webbing
on feet

Dorsal fin more arched than in Pacific Treefrog

       .

Males call

      . .     

General Description:
Boreal Chorus Frogs are small anurans reaching lengths of up to around 38mm (1.5 in.).  The ground color of these frogs varies from shades of brown, gray or green.  Boreal Chorus Frog dorsal coloration usually includes three dark stripes (these may be broken).  Boreal Chorus Frogs have a dark eye stripe similar to that of the Pacific Treefrog, but it extends to the groin area (Pacific Treefrog eyestripes end above the shoulder).  They may have a dark triangle pattern on their head.  The ventral coloration is yellowish, cream or white and there may be dark markings on the throat and chest.  Boreal Chorus Frogs have long toes with small toe pads and limited webbing between the toes (Pacific Treefrogs have more pronounced toe pads).  Male Boreal Chorus Frogs will call during the breeding season, making a loud chirping sound.  The call is short in duration, and they may repeat it 30 to 70 times per minute.

In the Pacific Northwest, Boreal Chorus Frog tadpoles can be distinguished as Hylidae tadpoles by the fact that the eyes are on the margin of the head rather than being inset.  Boreal Chorus Frog tadpoles are brown dorsally, have a white ventral coloration and their intestines are visible.   The tadpoles reach a size of around 30mm (1.2 in.) before metamorphosing.   Boreal Chorus Frog tadpoles are difficult to distinguish from Pacific Treefrog tadpoles, with the main difference being the more highly arched dorsal fin in Boreal Chorus Frog tadpoles (Nussbaum et al. 1983).

The eggs of Boreal Chorus Frogs are small, around 1 mm (1/25th in.) in diameter.  They are pigmented and are often hard to find.  They are laid in clusters of 30 to 75 and are generally attached to submerged vegetation or debris.

Idaho Distribution:
In Idaho, the Boreal Chorus Frog can be found in the eastern portion of the state, and along the Snake River Plain to the western border of the state.

South-central Canada and most of U.S. east of Rocky Mountains. Absent from most of southeastern Coastal Plain, New England, and northern Appalachians.

The model greatly under predicts the distribution on the map.

Habitat:
Found in moist habitats near breeding ponds, ditches, and marshes; found above 2000 m in Idaho.

Boreal Chorus Frogs are typically found in marshy vegetated areas. During the breeding season, they are usually associated with a water source such as irrigation ditches, marshes, ponds and lakes. The water source is often vegetated, providing both cover and attachment sites for their eggs.  At times other than the breeding season, they can be found in grassy or moist vegetated areas.

Diet:
Metamorphosed frogs eat various small terrestrial arthropods. Larvae eat suspended matter, organic debris, algae, and plant tissue.

Ecology:
Hibernatesclick here for definition/aestivates. Inactive in winter in northern range. Active day and night when breeding. Generally diurnalclick here for definition in cooler months of spring and fall, more crepuscular and nocturnal in hot weather. When inactive, hides in water, thick vegetation, under objects on ground, or in rodent burrows. Local populations may include a few dozen adults or as many as tens of thousands of individuals. Garter snakes and tiger salamander larvae prey on tadpoles.

Reproduction:
Congregations of singing males initiate breeding season with loud distinctive calls. Females fasten packets of eggs to vegetation. Aquatic larvae metamorphose in spring or summer, and become sexually mature in first, second, or third year. In Idaho, adults breed between March and June, depending on elevation and latitude.

Conservation:

Status:

Unprotected nongame species

Global Rank:

G5

State Rank:

S4

Important State Reference:
Clark, R.J., C.R. Peterson, and P. E. Bartelt. 1993. The distribution, relative abundance, and habitat associations of amphibians on the Targhee National Forest. Final report to the Targhee National Forest, St. Anthony. 16pp.


Species description, key characteristics and original work by John Cossel Jr. © 1997
Species ecological information from Groves et al. ©1997.
Original images provided by Charles R. Peterson, Edward Koch and Charlotte C. Corkran,© 1997
Design and Optimization by Ean Harker©1999, 2000.
DAI layout by Stephen Burton, and Mike Legler © 1999.