To call, a Chorus Frog squeezes air from its lungs across its vocal cords. The inflated throat sac amplifies the sound like a loudspeaker. /ED POROPAT Special to County Life

Land Trust discovers five new populations of Chorus Frog

By Ed Poropat
“Kreeeeeek……kreeeeeek……kreeeeeek……” – a distinct sound emanates from a shallow roadside pond, the rolling call reminiscent of someone rubbing their finger across a barber’s plastic comb. Early spring is once again breeding season for the tiny Chorus Frog. These minute amphibians emerge from hibernation in early April and begin their explosive breeding cycle, calling intensely for only a few short weeks before going silent for the remainder of the year. They are among the earliest frogs to call in our area.
With the recent warm weather, Haliburton Highlands Land Trust (HHLT) biologists and volunteers have been sweeping parts of the County in search of these declining amphibians. And, with great success! Recently, Paul Heaven of Glenside Ecological Services Ltd., HHLT’s project biologist, discovered five previously unknown breeding populations within the Marigold Wetland Complex, adding significantly to the few remaining sites in southern Haliburton County. These breeding locations have extra significance as they lie within a swath of land dubbed the Highlands Corridor. The local Land Trust has expended an enormous amount of time and energy not only documenting what species reside within this area, but also advocating to protect large portions of it. The Corridor would help mitigate the negative impacts of climate change and allow continued movement of species through connectivity.
A Chorus Frog can be green to brown in colouration, with dark longitudinal striping along the back. It will show a dark line running from the tip of the nose, through the eyes, and along its side to the back legs. Its thin, white, upper lip seems to glow in the sun. Chorus Frogs can pack quite a punch for their size. Their dry, rising trill can be heard day or night at quite a distance, given an adult frog is not much bigger than your thumbnail. Unlike woodland pools and large wetlands that Spring Peepers thrive in, Chorus Frogs seek out shallow, grassy, ephemeral pools to lay their eggs. They do not cope well with competition, especially if fish are present. Thus, a Chorus Frog’s early life is a race against time and weather. They must complete their cycle of egg, to tadpole, and finally metamorphosing to an adult before their temporary pool dries up. A particularly hot, dry spring can spell disaster for a local population of these tiny amphibians.
Chorus Frogs have experienced enormous declines in the past few decades. Although the Carolinian population appears to be stable, the Canadian Shield and eastern Ontario population has been steadily disappearing. Haliburton County has not been immune to this decline, and many of our traditional Chorus Frog sites have gone silent in the past decade. The discovery of these new locations is therefore very exciting. Sadly, it appears to be a race against time to determine the causes of this decline. Although habitat loss is a major contributor in some areas, other factors must be at play also.
If you’d like to assist the Haliburton Highlands Land Trust in their endeavor to understand the distribution and abundance of these tiny frogs, you can help by simply using your cell phone. If you think you have heard chorus frogs, simply make a brief recording and email it to the Land Trust with a location. The recording can be verified, and you will have made a significant contribution to our knowledge of local fauna. The Land Trust is appreciative of the generous funding from Environment Canada & Climate Change, Habitat Stewardship Program to support this project.
So, get out there before the bugs arrive, and enjoy the calls that truly herald the coming spring … the call of the Chorus Frog.