Amphibians of North Carolina
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NC Records

Pseudacris collinsorum - Collinses' Mountain Chorus Frog

Pseudacris collinsorumPseudacris collinsorum
Taxonomy
Class: Amphibia Order: Anura Family: Hylidae Subfamily: Hylinae Synonym: Pseudacris brachyphona
Taxonomic Comments: Until recently, the Mountain Chorus Frog (Pseudacris brachyphona) was treated as a single species that ranged from mountainous regions of eastern Kentucky, southeastern Ohio, and western West Virginia southwestward through the Appalachian region to central Alabama. Subsequent molecular studies have revealed that this species consists of two well-defined evolutionary lineages that include a northern clade that occurs from the northern portion of the range southward to northern Alabama, and a southern clade that occurs in Alabama, northern Georgia, and southwestern North Carolina. Ospina et al. (2020) conducted detailed studies of the complex and found that members of the two clades constitute two species based on genetic differences, call characteristics, and habitat preferences. The members of the southern clade are now recognized as Collinses' Mountain Chorus Frog (P. collinsorum), while those of the northern clade as the Appalachian Mountain Chorus Frog (P. brachyphona, sensu stricto). The Tennessee River is a major physiographic barrier that separates the two species.
Species Comments: Prior to the recent taxonomic split, most of the published literature on the life history of mountain chorus frogs were from populations in West Virginia, Kentucky and elsewhere that are now recognized as a separate species (P. brachyphona sensu stricto). As such, we have very little detailed information on the life history of the southern form of this complex, P. collinsorum.
Identification
Description: This is a small hylid with granular skin and slightly enlarged toe pads. The ground color is variable, with individuals having tan, grayish, or light greenish brown coloration above. Some individuals have an ‘‘inverted parentheses’’ dorsal stripe pattern that is commonly seen in P. brachyphona, but others may have broken stripes or lack a dorsal pattern altogether (Jensen et al. 2008, Ospina et al. 2020). A dark triangular patch is often present between the eyes, and a dark stripe extends from each nare posteriorly through the eye before terminating just past the tympanum. The upper lip is pale or whitish and contrasts with the darker stripe above. The ventral surfaces are white and unmarked, except for males that have a dark throat. The concealed portions and the undersides of the legs have yellowish pigmentation. The males average slightly smaller than the females. Jensen et al. (2008) reported a range of 24-32 mm SUL for males in Georgia versus 27-34 mm for females. Females from Cherokee Co., North Carolina averaged 33 mm (range = 29-37 mm) for females versus 29 mm (26-32 mm) for males (McCoy et al. 2021).

The tadpoles are uniformly medium brown or brassy and have a narrower tail fin than other chorus frogs (Jensen et al. 2008). The fully grown tadpoles can grow to 35 mm TL and the metamorphs are around 8 mm TL (Jensen et al. 2008).

This species is similar to both the Upland Chorus Frog (P. feriarum) and the Spring Peeper (P. crucifer). The former usually has three dark longitudinal stripes that run down the back that may be either complete or broken. However, specimens that have reduced patterning are easily confused with similar specimens of P. collinsorum and are perhaps best identified by voice. Pseudacris feriarum occurs in nearby eastern Tennessee, but has yet to be found sympatrically with P. collinsorum in western North Carolina. The Spring Peeper typically has an 'X' pattern on the back and lacks the lighter upper lip. Pseudacris collinsorum is morphologically indistinguishable from P. brachyphona and is best identified based on its geographic range or by genetic markers (Ospina et al. 2020).
Vocalizations: The advertisement call is a series of short, nasally 'wreaks' that are repeated over and over and issued about every second or so depending on the prevailing temperature. The call is distinctive and unlikely to be confused with any other frog that occurs in western North Carolina. Males will call both during the day and night, but chorusing is most intense within the first few hours after nightfall.
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Observation Methods: Local populations are most readily detected by riding roads on warm, rainy nights to search for migrating adults, or by listening for calling males during the breeding season. The small egg masses can be easily seen in the shallow pools that are used as breeding sites.

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AmphibiaWeb Account
Distribution in North Carolina
Distribution Comments: Pseudacris collinsorum is found in southwestern North Carolina, northern Georgia, northeastern Mississippi, and northern and central Alabama to as far south as the northern Coastal Plain (Ospina et al. 2020). This species was thought to be rare in North Carolina prior to 2008, with only a few historical sites known from Cherokee Co. Lori Williams of the NC Wildlife Resources Commission has subsequently documented over 200 breeding sites in central and western Cherokee County and southwestern Clay County.
Distribution Reference: Ospina et al. (2020)
County Map: Clicking on a county returns the records for the species in that county.
GBIF Global Distribution
Key Habitat Requirements
Habitat: Local populations are often found near the interfaces of forested and more open habitats such as agricultural fields or roadways. Although breeding often occurs on deforested land that is rather distant from forests, most adults appear to retreat to upland, montane forests after breeding in valley-bottom wetlands. Local populations are associated with fairly dry forests, including pine-oak woodlands and dry-mesic hardwoods (Ospina et al. 2020). This contrasts with the more mesic stands of hardwoods that are preferred by P. brachyphona (Barbour 1957, Green 1952). Like other species of Pseudacris, the adults are non-arboreal and are only capable of climbing low vegetation.

In North Carolina, the adults mostly breed in small seasonal wetlands that lack fish. The males have been heard calling from flooded roadside ditches, drainage ditches in pastures, remnant wetland patches (usually with scrub/shrub vegetation), low lying grassy swales, floodplain bogs and wetlands (particularly around the fingers of lakes), forested vernal pools, wet toe slopes of forested hillsides, stream riparian zones, and even driveway puddles (Lori Williams, pers. comm.). Small farm ponds and drainage ponds are also occasionally used.
See also Habitat Account for Dry-Mesic Montane Forests with Isolated Pools
Life History and Autecology
Breeding and Courtship: Much of our knowledge of the breeding biology of members of the Pseudacris brachyphona species complex comes from studies of P. brachyphona in areas such as Kentucky and West Virginia (e.g., Green 1952, Barbour 1957). The life history and breeding biology of P. collinsorum is presumed to be very similar to that of P. brachyphona, but a detailed life history account is currently unavailable.

The adults appear to migrate from forested slopes to the breeding sites during the winter months following bouts of relatively warm rainy weather. Breeding may begin as early as December in some populations and typically terminates by late March. McCoy et al. (2021) observed breeding adults from 4-24 March at one site in Cherokee County. The males typically call from the edges of small flooded depressions to attract mates. Very little is known about social aspects related to calling behavior.
Reproductive Mode: Each female attaches several small, loose egg masses to leaves, stems, or other support structures in the ponds (Mount 1975). McCoy et al. (2021) reported that females at a western North Carolina site laid from 9-32 egg masses each (mean = 16.5 masses), with each mass containing from 1-113 eggs. Most masses contained from 12-24 eggs (mean = 20 eggs per mass). Individual females laid from 227-496 eggs (mean = 338).
Aquatic Life History: Almost all aspects of the life history and ecology of the larvae are undocumented.
Terrestrial Life History: McCoy et al. (2021) tracked adults at an orchard site in western North Carolina that had a mix of fields, orchards, and deciduous forest. Adults were originally tracked using transmitters from either two ponds or a set of puddles that were used as breeding sites in non-forested areas of the site. Individuals moved from 11-476 m from the breeding sites (mean = 220 m for a set of puddles and 106 m for two ponds). Movements were most commonly observed on warm nights after rain events, and the final habitat of the great majority of individuals was in fields or orchards rather than forest habitat. Animals in this study were only tracked for 20-31 days, and the authors surmised that many may have ultimately moved to forested sites if they could have been tracked longer. Most animals were tracked from two ponds that were no closer than 177 m from the nearest forest habitat. Those that were tracked from puddles that were closer to forest (55-103 m depending on the direction) mostly moved into the forest. Additional studies of longer duration are needed to better understand terrestrial habitat use by this species.
General Ecology
Community Ecology: This species uses ponds that are shared with both aquatic predators and other anurans, but we have no information on ecological interactions with other community members.
Adverse Environmental Impacts
Status in North Carolina
NHP State Rank: S2
Global Rank: G2
Status in North Carolina: SC
Status Comments: Populations in North Carolina show no evidence of widespread population declines and appear to be stable.

Recording Gallery for Pseudacris collinsorum - Collinses' Mountain Chorus Frog

2022-03-07. Cherokee Co. Jim Petranka and Becky Elkin -

2022-03-07. Cherokee Co. Jim Petranka and Becky Elkin - Air temp. = 55F.

2022-03-08. Cherokee Co. Jim Petranka and Becky Elkin - Chorusing at 10:15 AM; air temp. = 46F

Photo Gallery for Pseudacris collinsorum - Collinses' Mountain Chorus Frog

2 photos are shown.

Pseudacris collinsorumRecorded by: Jim Petranka and Becky Elkin
Cherokee Co.		Pseudacris collinsorumRecorded by: Sam McCoy
Cherokee Co.