The Release Call of the Western Toad

Unlike many other frog and toad species, most Western Toads (Bufo boreas boreas) do not use a vocal call to advertise for mates.  So, if you heard frogs calling this spring, you were most likely hearing Pacific Tree Frogs (Pseudacris regilla), and not Western Toads.

This interesting fact left us with one question: What is the meaning of these Western Toad calls recorded by our friend Ian Routley at Pavilion Lake?

The answer is actually quite interesting, but before we tell you, we will give you a hint:

Image recorded by Ian Routley at the same time as the sound recordings, May 7th 2017 at Pavilion lake.

If you guessed that these sounds were cries of passion, then you were incorrect.  These sounds are actually what herpetologists refer to as “release calls”.  You see, when frogs mate, the male grabs the female around the waist and snuggles up tight while he fertilizes her eggs.  But sometimes a problem occurs when a male grasps another male instead of a female.  In this case the male who has been mistakenly grabbed begins to protest by uttering a series of chirps that sound not unlike the peeps of a baby chick – the “release call.”  A way of saying: “please let go of me, you have the wrong mate!”  While they are shy to speak for most of the rest of their lives, male Western Toads demonstrate the courtesy of speaking up to let another fellow know when he is wasting his time.

The most important sites for Western Toad breeding in the Lillooet Area are the wetlands of the Fountain Valley, and the Pavilion Lake series.  These sandy bottomed lake host breeding populations of toads which come together in the spring to mate and deposit large colonies of eggs.  Throughout the summer you can look in the sunniest parts of these lakes and maybe you will see large schools of charcoal black Western Toad tadpoles.  In the late summer, drive with care and try not to hit the newly metamorphosed western toadlets as the move out from their natal wetlands, and into the upland forests that they use for foraging and hibernating.

The International Union for the Conservation of Nature has listed Western Toads as Endangered globally due to massive habitat loss, and population declines at the southern edge of their range in the US.  Though they also occur in western Alberta, and perhaps the southern Yukon, British Columbia is the core of their range, and the most important region for Western Toad conservation globally.

Like most other amphibians species, the greatest threat to the Western Toads are loss of habitat, and pollution.  So if you want to be a friend to the Western toad, the most important thing you can do is to participate in efforts to protect our precious wetlands!

If you are interested to learn more about Western Toads, the BC Frogwatch Program has some very good information.




by Splitrock Environmental