By David Hawke -- With temperatures sneaking up past the freezing point, the frog he would a wooing go. Although the cool temperatures of late have delayed some aspects of spring, the amorous frogs have been jostling for position in the icy waters.
In our neck of the woods, we have eight species of frogs and one toad (there are 13 in all of Ontario, so we have a pretty good share of the list), each with their own parameters of when to sing, and when not to. Some are early spring, a few are mid-spring and a couple wait until the true warmth covers the land. This information we know to be true as for decades many people with a penchant for listening to frogs have made notes. And shared them. Data! Crunch it!
There have been frog calling programs set up to cover the province, and others to cover just the local wetlands and wet spots. I’d like to give a bit of a shout out to two Orillia area naturalists who have kept years and years of info on these spring callers: the late Bill Cattley, who recorded everything natural long before it was trendy to do so, and more recently, Muriel Sinclair of the Orillia Naturalists’ Club who has organized frog walks every Monday evening in April for at least the past three decades (although this year the walks had to be severely altered). An example of the original citizen scientists!
Identifying frogs is fairly easy as each species has its own unique song. Spring peepers “peep” until a few hundred join in and then they sound like old-fashioned sleigh bells! These guys are the easiest to hear because they can be almost deafening on warm April eve.
Wood frogs “quack” or “chuckle” and hang out in clustered groups within the shallow edges of a swamp. Sometimes ‘frog balls’ are formed as many males will attach to a female until the whole mass sinks below the surface (see the picture).
Chorus frogs make a sound like someone running a fingernail down the teeth of a comb. They are often mixed in with peepers and it takes a good ear to pick them out. More on chorus frogs in a minute.
Leopard frogs make a single note that sounds like a ‘snore’. Usually not a part of the first frog choruses but a springtime species once the weather warms a little.
Mink frogs are a bit on the uncommon side around here but can be found in stream areas. They have a gentle call, reminiscent of clicking stones together underwater (and we’ve all done that, right?).
Green frogs will be calling as we get into May, and these ones are pretty common and have that familiar “plucking a rubber band” hit single. Just about every wet spot you find will have green frogs.
Bull frogs and tree frogs are typically the summer frogs, the former with that rolling basal “jug-o-rum” heard in big water places; tree frogs do their calling not from the water but high up in trees, sounding a bit like a flycatcher with their very loud “reeep”.
Oh, and toads. Toads have a long drawn out “trill”, also mixed in with the late spring frog calls.
Now for the tricky bit. There are two species of chorus frogs in Ontario, the Western and the Boreal. They look the same (other than the Boreal has slightly longer back leg) and sound the same (fingernail on a comb), but the Boreal’s call is a smidge shorter than the Western’s. Boreal chorus frogs are usually found on north shore of Lake Superior, while Western chorus frogs are residing in southern Ontario and extending into southern Quebec. So, what’s the problem?
The Western chorus frog is on the federal government’s species at risk list, their population being so low that they are considered as Threatened in Canada. And with that designation comes some legal protection for the frogs and their habitat. However, the provincial listing of Western chorus frog deems them not at risk, indeed even common. So, rare in Canada but common in Ontario.
In the vast field of biology, the ability to sample DNA has revealed that the Western chorus frogs are actually in two separate populations in Ontario, one group being south and west of Toronto (referred to as the Carolinian biozone) and the other group is north and east of Toronto going up to the St. Lawrence River. The south group are in low numbers while the east group of Western frogs are stable. Confused yet?
And there is chatter amongst herpetologists (those that study reptiles and amphibians) that maybe perhaps the Western chorus frogs that live north of Toronto are actually Boreal chorus frogs that have extended their range southwards. All of which may lead to the conclusion that only the southern population of Western chorus frogs should have Species at Risk protections. This little kettle of conundrums is on full boil right now.
So for now, if you are able to take a health break and wander by a wetland, listen carefully to that cacophony of frog calls and try to pick out a ‘fingernail on a comb’ call. If you can, then you are now part of this frog wooing debate.
David’s Notebook: Snow next weekend? What’s up with that!?
© 2020 David J. Hawke