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Pickerel Frog

Overview:

Scientific Name: Rana (Lithobates) palustris

Size: 1.7 – 3.4” (adult size)

Status: Previously present to rare over the Great Lakes region but can be locally abundant where suitable habitat exists

Michigan State Status: Special Concern

MDNR Wildlife Action Plan Status: Species of Greatest Conservation Need

Habitat:

Found in or near bogs, fens, ponds, streams, springs, sloughs, and lake coves. Prefer cool, clear waters. Often inhabits grassy stream banks and areas where streams flow into bogs, marshes, or weedy ponds.  

Conservation:

Although the pickerel frog is considered stable at the federal level, many localized populations are in decline and the species is listed as being of special concern in Michigan. Destructive activities such as increased urbanization and clear-cutting are degrading suitable pickerel frog habitat. Novel pathogens such as amphibian chytrid fungus (Batrachochytrium dendrobatidis) and other ranaviruses have the potential to devastate this species. Although not well examined, the collection of pickerel frogs for use as bait may also contribute to their localized decline.  

Best Management:

Identify and protect quality pickerel frog habitat containing extant populations. If harvest is required in suitable pickerel frog habitat, consider harvesting during late fall to early winter. Implement a rotated tree harvest technique to eliminate the repercussions of clearcutting. If possible, maintain an understory as well as downed woody debris and a sufficient leaf litter. If vernal pools are present, do not impact the pool depression or core buffer area within a minimum of 100 feet and aim to protect a wider buffer of 600-1000 feet surrounding that. Maintain a forest canopy (>50%) and habitat connectivity between breeding sites and adjacent habitat. Ensure course woody debris is scattered and that the litter layer and understory vegetation are maintained to provide appropriate microclimates. If present, avoid disturbing riparian zones and adjacent terrestrial habitat but if riparian harvest is necessary, maintain understory and install temporary erosion control. Proper decontamination protocols should also be followed if gear or personnel are in contact with pickerel frog habitat. Regulations regarding pickerel frog collection for use as bait should be examined further. Provide egg laying structures by submerging finely brushed trees and ensure the presence of native aquatic plant communities. Create basking structures by fully or partially submerging logs and other objects.  

Adult Coloration:

Angular, squarish brown back spots that are outlined in black which are arranged in two irregular rows between the lightly colored dorsolateral folds (raised ridges running extending down each side of the back). The body is light brown, tan, grey or olive in color. Rarely, the spots will converge into lengthwise stripes. The groin and inner thighs may be bright yellow, orange, or gold while the throat and belly are whitish.  

Adult Characteristics:

Medium sized typical looking frog with prominent spots. Males are slightly smaller with enlarged thumbs during breeding season. Their call is a low-pitched snore-like croak similar to a Leopard Frog’s but shorter and weaker.  

Mass: 2.5 – 3 g 

Typical Lifespan in Wild: Unknown, 2 – 3 years 

Breeding Interval: once annually  

Breeding Season: February- May  

Range number of offspring: 2000 – 3000 eggs 

Average number of offspring: 2500 eggs 

Range time to hatchling: 11 – 21 days (metamorphosis: 90 days) 

Average age at sexual/reproductive maturity (females):   

Average age at sexual/reproductive maturity (males):   

Diet: Pickerel frogs primarily prey on terrestrial arthropods such as insects and arachnids but other food sources include snails, crayfish, isopods, and aquatic amphipods. Tadpoles consume mostly algae as well as other organic plant material.  

Known Predators: Pickerel Frogs, Bald Eagles, Mink, Bullfrogs, and Green Frogs.  

Larvae Characteristics:

Tadpoles reach a maximum length of 2 – 3” prior to metamorphosis.  The back is green, greyish-brown, or brown with black and yellow spots. The belly is iridescent white or cream. Tail fins are heavily pigmented with dark spots or blotches.  

Species Confused With:

Most similar to Northern Leopard Frogs. Tadpoles of Northern Leopard Frogs have less heavily pigmented fins with light or faint spots. Adults have more rounded spots that are not arranged in a row and have a lighter border.  

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