Ushering in Spring with Choruses of Chorus Frogs

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A Spring Peeper calling in the mountains of Virginia – Houston Chandler

Spring Peepers (Pseudacris crucifer) are one of the most abundant and well-known frog species living in the eastern United States.  Having a mostly nondescript appearance, Spring Peepers can be recognized by the cross pattern on their backs that gives the species the name crucifer, although this pattern is not present in all individuals.  Spring Peepers are almost certainly better-known for the characteristic ‘peep, peep, peep’ calls that are produced by advertising males.  On warm rainy nights, calls occur at high frequencies, and males often congregate in large numbers.  When calling en masse, Spring Peepers can generate an ear-splitting chorus, drowning out other early season species that are trying to attract mates.  Spring Peepers are often considered a sure sign that spring is on the way as they are one of the first species to emerge from winter retreats.  However, there is significant regional variation, and the start of spring is relative.  For example, in southern Georgia, Spring Peepers often begin calling in December, while in the mountains of Virginia, they rarely emerge until sometime in March.  Regardless of the time of year, Spring Peeper emergence and breeding activity does signal that warmer weather is on the way, and Spring Peepers typically share breeding wetlands with many other well-known early season breeders, including several species of ambystomatid salamanders and Wood Frogs (Rana sylvatica).

A Spring Peeper sitting on top of a Wood Frog egg mass – Houston Chandler

Spring Peepers are members of Genus Pseudacris or chorus frogs.  This Genus contains approximately 17–19 species, depending on which taxonomy you prefer, and members can be found across the United States, Canada, and even into parts of northern Mexico.  Both Spring Peepers and Western Chorus Frogs (P. triseriata) are surprisingly cold tolerant, ranging relatively far north into parts of Canada.  Chorus frogs received the name Pseudacris from their calls that often resemble those of various insects (i.e., false locust).  While many species of chorus frogs are fairly nondescript in appearance, Ornate Chorus Frogs (P. ornata) are one of the prettiest frog species that can be found in the U.S. (read more here).  While Spring Peepers are undoubtedly the most appreciated sign of spring, many species of chorus frogs are winter or early spring breeders, including the above-mentioned Ornate Chorus Frog and two species that I highlight below.

A Little Grass Frog sitting on the tip of my finger – Houston Chandler

The first example is the Little Grass Frog (P. ocularis). Little Grass Frogs are the smallest frog species found in North America, with adult frogs maxing out at less than one inch.  While these frogs can be heard calling for most of the year (especially in Florida), they often begin breeding in late winter or early spring.  In Georgia, I have found them sharing wetlands with Ornate Chorus Frogs and Spring Peepers.  Little Grass Frogs are a Coastal Plain species, breeding in shallow, grass-filled wetlands that nowadays often include roadside ditches.  As an aside, when I was younger, my dad once bet me that I could not find a Little Grass Frog calling from beside the road.  It took me little time to locate the frog, a sure sign of the herpetological field skills that I was already developing.  Because of their small size, Little Grass Frogs are difficult to study, and relatively little is known about their ecology when compared to other frog species.  They appear to have remained common in much of their range and have undoubtedly benefited from an ability to breed in shallow, artificial wetlands.  Still many populations have likely suffered from the general loss and degradation of wetland habitats across the southeastern United States. 

A Mountain Chorus Frog calling from a roadside ditch – Houston Chandler

My second example of an early-season chorus frog is the Mountain Chorus Frog (P. brachyphona), which can be found in the Appalachian Mountains from Pennsylvania to Georgia.  Like the Little Grass Frog, Mountain Chorus Frogs are poorly studied and documented in many parts of their range, with detailed information about parts of their life history completely lacking.  Their range just passes through western Virginia, which is where I got my first experience with this species.  On a rainy night in late March, I stood beside a road to see a shallow ditch come alive with calling Mountain Chorus Frogs and one seemingly out of place Spring Peeper.  Mountain Chorus Frogs generally begin breeding activity in March or early April and will breed in a variety of shallow pools.  In Virginia, there are few records of known Mountain Chorus Frog populations, and there is concern that species could become extirpated from its small range in the state.

Larval Red Salamander sitting near Mountain Chorus Frog eggs – Houston Chandler

A new joint project among researchers in Virginia Tech’s Fish and Wildlife Department, The University of Virginia’s College at Wise, Virginia Highlands Community College, and the Virginia Division of Wildlife Resources aims to improve our understanding of the Mountain Chorus Frog distribution in Virginia.  The project is gathering records of the species from Virginia to better understand its distribution and the current extent of breeding populations. Many of the observations come directly from the public in often remote areas of the state.  You can learn more about the project and submit records at the following link: https://www.mtchorusfrog.fishwild.vt.edu/index.html.

Chorus frogs are generally overlooked both by the public and the herpetological community.  This genus includes many fascinating species that are often poorly understood ecologically.  Their small size makes them challenging to study using conventional methodologies.  Even though other species are more colorful or perhaps more interesting, I will always have a soft spot for Spring Peepers.  A wonder to listen to on cool, rainy nights and a sure sign that spring (or at least warmer weather) is on the way.