BRAS D’OR BIOSPHERE: Toads sing in May

The Mi’kmaw word for May is “Squoljuiku’s” which translates to “frog croaking time,” a noisy month in the Bras d’Or Lake Biosphere due to the desperate songs of amphibians looking for mates.

Although we are all familiar with the short and frantic calls of the spring peeper, there are actually several types of frog and a toad which contribute to the spring amphibian chorus.

The spring soundscape in the biosphere is enriched by the songs of spring peepers (Jijawej), wood frogs (Samqwani’j), northern leopard or grass frogs (Samqwane’j), pickerel frogs (Mkoqte’j), and the American Toad (Sqolj), each contributing a unique song to the medley.

- Advertisement -

The term amphibian is from the ancient Greek term amphibios which means “both kinds of life,” referring to the young stages living in water and the adult stages living on land. In the Bras d’Or Lake Biosphere, we have amphibious frogs, salamanders and one species of toad.

Because of this dependence on two different habitats to complete their life cycle, amphibians are vulnerable to many kinds of ecosystem insults. Any alteration to freshwater wetlands impacts the early stages of the amphibians’ life cycles and modifications to nearby forests and grasslands impact later life stages. In addition, environmental contaminants are readily taken up through the amphibians’ thin skins. According to a letter in the scientific publication Nature in 2011, amphibian population declines are globally significant.

We have little data from the Bras d’Or Lake Biosphere Reserve but we would like you to listen for the spring amphibian chorus and let us know of any changes from one year to the next. We all anxiously await the early calls of the northern spring peeper. Let’s start to tune our listening to some of the other members of the choir.

That sharp soprano trill in the nights and early mornings of spring is contributed by male American toads, floating in their favourite pond and anxiously trying to attract a female. Sqolj is the last amphibian to go into hibernation in the fall and is full of desperate sexual vigour in the spring. They have a haunting call, with their long vibrating vocals filling the night air in May and June. If a group of males huddle together to produce a chorus of trills, each desperate male will choose a different note for his call, producing a pleasant harmony in the cold spring air.

Sqolj seems to have been given a bad rap. I guess that a fat, gnarly, hopping animal that has been reputed to spread warts to humans does not engender a warm, fuzzy feeling. The humble toad should be viewed with respect because the adults are voracious consumers of many garden pests such as slugs. They do not give you warts. This rumour may have started because their skin does produce a slightly noxious substance which deters potential predators. It will only affect you if you lick the toad or rub your eyes after handling one. Stop your playful puppy from putting one in his mouth or the toxin produced on the toad’s skin could make him ill, frothing at the mouth. Similar toads that live in the tropics produce a deadly toxin!

These are American toad tadpoles.

The American toad adults are found in a wide variety of terrestrial habitats ranging from mown grass, to gardens, and heavily forested areas. Ideal adult habitats are damp areas with dense vegetation and lots of insects. They inhabit ponds only during the breeding season. Breeding occurs in many types of freshwater such as warm, shallow ponds, shallow streams and river margins, and even large puddles and roadside ditches. There is evidence that they prefer water bodies with few or no fish and return to the same water bodies where they were born.

During this special time of year, the toads’ breeding antics may resemble a clumsy orgy. When a singing male encounters a receptive female, he latches onto her back and they float, entwined, while his sperm fertilizes her expelled stream of gelatinous eggs heading to the bottom. It sometimes gets a bit confusing for the poor guys and several males may try to attach to the same female at the same time, forming what is commonly called a “toad knot.” Keep in mind that the females are much larger than the males, it must be a bit of a nuisance nonetheless as she tries to maintain a clear path for breathing while concentrating on expelling the streams of eggs. The process of the male latching onto the female for fertilization is called “amplexus.”

An American toad egg mass is pictured.

After the amplexus orgy, eggs are laid in two sticky gelatinous strands which are wrapped around plants living on the bottom of the water body. The eggs of this amphibian are easy to identify because they are countershaded (black on top and white on the bottom). The eggs are about one to two millimetres in diameter and the strings may contain several thousand.

The larvae that hatch from eggs a few days or weeks later are called tadpoles and they stay in that stage for up to two months. The tadpoles are easy to identify. They are small when compared to tadpoles of other species, very dark and have skinny little tails compared to their round bodies. They grow to over a centimeter (cm) in length before transforming. Newly-metamorphosed toadlets are usually around one cm long when they first emerge in September. They are mini-toads with an attitude and colouration similar to that of full grown adults.

The little toadlets move out of their watery nursery and disperse into the nearby fields and forests. The adults live in many habitats in the Bras d’Or Lake Biosphere with lots of moisture and plenty of insects to eat (yes, that includes mosquitoes and black flies). Some naturalists believe that a single Sqolj can consume up to 10,000 insects a year.

The mini toads grow rapidly in the first year. By their second birthday, they are near full size and the males are ready to mate. The females are a bit slower to mature and will be ready by their third birthday. They can live up to 10 years, overwintering in burrows that they dig extending below the soil frost line.

This is an example of a toadlet’s size.

The American Toad may not be the most charismatic resident of the Bras d’Or Lake Biosphere but it does play a valuable role. It has the ability to transform thousands of mosquitoes, blackflies and slugs into rich organic toad fertilizer. Think about the humble toad when you plan lawn care this spring. That chemical nitrogen-rich lawn fertilizer which makes your grass a verdant green is toxic to these little garden helpers. Let’s aim for a less green, more diverse lawn and encourage Sqolj to take up residence and help you with your pest problems.

The American Toad population appears to be in good shape according to the International Union for the Conservation of Nature. However, we would like to keep a closer watch on this species. Amphibians are indicators of environmental change. If you would like to help keep track of the health of our biosphere populations, please become a Frogwatch volunteer by registering at: https://www.naturewatch.ca/frogwatch/.

Dr. Annamarie Hatcher is a consulting ecologist and a board member of the Bras d’Or Lake Biosphere Reserve Association. For more information about the Bras d’Or Lake Biosphere Reserve Association, please visit http://blbra.ca/ or check out our Facebook page.