Wild Ideas: Some frogs are landlubbers

We often think of frogs as being aquatic creatures, but many spend some or most of their lives on land, returning to water only to breed. Among these is the pickerel frog, which often turns up in my yard.

Because of such amphibians, and many other native animals that lurk in the grass or under rocks and logs around the perimeter of the house, I tend to go easy on trimming, trying to find a balance between supporting and enjoying our native wildlife and keeping unwelcome critters, such as house mice and copperheads, at bay.

A small pickerel frog enjoys the moisture and the insects it attracts near the outside water tap at the author’s house.
A small pickerel frog enjoys the moisture and the insects it attracts near the outside water tap at the author’s house. Pam Owen | Rappahannock News

During a dry stretch late this spring, I held off trimming for a while and was rewarded with finding a young pickerel frog near my outside water tap. It was during one of the brief dry spells we’ve had since winter, and the frog likely was hanging around the tap not only to hydrate itself with the water that accumulated from the leaky connection to the hose, but also to feed on the insects attracted to the moisture.

The Virginia Fish and Wildlife Information Service (VaFWIS) gives a size range of 1.75-3.5 inches for the pickerel frog (Rana palustris). Females are larger than the males but otherwise generally similar in appearance.

In doing a bit of further research, I found that during the breeding season and summer, the male can be recognized by its swollen thumbs, according to the Rhode Island Vernal Pools (RIVP). The pickerels I’ve found in the yard have been on the small side, so are likely males, juveniles or both. Next time I find one, I’ll know to check its thumbs.

Pickerels breed from March through May, and while many also breed at the ponds down the mountain from my house, those seem to be a biological sink, with any eggs quickly disappearing and no tadpoles appearing. The upper pond, by contrast, is packed with both every year. This difference in reproductive success among the ponds can probably be chalked up to the lower ponds being full of fish, which can consume amphibian eggs, while the upper pond is devoid of them.

During breeding time I can hear several pickerels at all the ponds belching out their mating calls, which Bernard S. Martof and his coauthors describe in “Amphibians and Reptiles of the Carolinas and Virginia” as “a low-pitched snore.” To me it sounds more like a large door with rusty hinges opening.

With flashlight in hand, I can usually spot most of the pickerels among the weeds near the water’s edge. Their distinctive coloring makes them easy to distinguish from the green frogs and bullfrogs at the ponds, and from the wood frogs that breed only in the upper pond and an old concrete tank nearby.

An avid frog hunter as a kid, I looked each spring for the lovely iridescent dark-brown spots with black perimeters set against a background of bronze to tan. The spots are roughly oblong to rectangular; the legs have similarly colored bars.

The aptly named leopard frog has similar coloring, but is much less common in Virginia and generally occurs more to the south and east of Rappahannock County. The VaFWIS species booklet for the pickerel does, however, list it as “known or likely to occur” in Warren and Culpeper counties. Although the booklet doesn’t elaborate on specifically where it occurs, I would guess it is in the lower elevations.

The pickerel, on the other hand, is known or likely to occur in all but the most southeastern of Virginia’s counties. Its range generally extends from the Canadian Maritime Provinces south to the Carolinas and west to southeast Minnesota and eastern Texas.

Pickerels mature in three years. According to VaFWIS, adults are found in a variety of aquatic habitats near wooded areas, but may venture into grassy fields or weed-covered areas during the summer where shade and shelter are available. They return to grassy, marsh habitat, such as around the ponds where I live, to breed.

Even when in aquatic settings, pickerels still spend most of their time out of water, entering into it only to avoid predation from birds, snakes and other predators, to lay their eggs and to regulate their temperature, according to RIVP.

Their mottled markings provide pickerels with good camouflage in the grassy environments where they primarily forage. There they prey on a wide variety of invertebrates, including beetles, caterpillars, true bugs, ants, spiders, harvestmen, sowbugs, mites, arthropods and worms. In the water, they feed on other amphibians, snails, crayfish and other small crustaceans.

A pickerel frog waits by a pond during the breeding season, well camouflaged by its coloring.
A pickerel frog waits by a pond during the breeding season, well camouflaged by its coloring. Pam Owen | Rappahannock News

In turn, pickerel frogs are preyed upon by snakes and other frogs, although they excrete toxins through their skin that can be distasteful to or even kill microorganisms, other frogs and predators, and can irritate eyes, mucous membranes or broken skin in humans.

Excretions from pickerels and other frogs among the 250 species in the Rana genus may also be therapeutically useful against infection, according to a study in the science journal “Biochimica et Biophysica Acta” in 2008.

For more about the pickerel frog, including photos and a recording of its call, visit the Virginia Herpetelogical Society, which also offers other tools for frog identification.

© 2014 Pam Owen

Pam Owen
About Pam Owen 346 Articles
Writer, editor, photographer, and passionate nature conservationist living in Rappahannock County, in the Blue Ridge Mountains of Virginia. Two favorite quotes: By E.O. Wilson, who coined the term "biodiversity," "Nature holds the key to our aesthetic, intellectual, cognitive and even spiritual satisfaction”; by Douglas Adams, “I love deadlines. I love the whooshing sound they make as they pass by.”