Frogs, Toads and Other Things

FROGS, TOADS AND OTHER THINGS  

March/April, 2011 issue
  
 Those  who watched the classic film “Deliverance” from the early 1970s will   not soon forget the disturbing scenes from this epic about four  canoeists  paddling down the wild Cahulawassee River in Georgia. The  movie, however, did  have a powerful environmental message that was way  ahead of its time. As a  naturalist though, I was really paying more  attention to the sounds in the  background – the piercing bleats of  Fowler’s toads. 
  
 We  can safely assume that the repeated screams of the Fowler’s toad were   not dubbed in for effect, but rather, had been calling naturally when  the scenes  were recorded. Certainly they are common in Georgia and  range all the way north  to Lake Erie where a small population of fewer  than a thousand can be found  along the lake’s north shore. We won’t  hear them in eastern Ontario, but we do  have nine or 10 other species  of frogs and toads to delight us as spring once  again makes its debut.
  
 Every  March for the past 10 years I have conducted a workshop on behalf of   the Community Wildlife Monitoring Program (CWMP) in which I am  involved.  The  workshops ease volunteers into the art of identifying  those mysterious sounds  that emanate every spring from the depths of  the wetlands. The purpose of the  program I operate is to monitor the  successes and failures of amphibians as a  way of determining the health  of the wetlands in our area. Frogs and toads are  very sensitive to  environmental changes and have become important indicators in  the CWMP  in the Bay of Quinte area. The long term goal is to delist the Bay of   Quinte from an Area of Concern to An Area In Recovery. 
  
 The  public is drawn to frogs and the program is an easy one to get people   excited about. Over 100 attended last year’s workshop, eager to learn  the  species of frogs and differentiate between the calls. For families,  there was  Ontario FrogWatch, and for those wanting the challenge of a  more structured  survey, the popular Marsh Monitoring Program, operated  through Bird Studies  Canada.
  
 The  frog chorus began very early last spring – some claimed hearing chorus   frogs as early as March 17th. Generally, it is the raspy notes of wood  frogs  that herald the spring chorus, sounding like a small misplaced  gathering of tiny  ducks quacking from wooded areas. They are the first  to call because Nature has  gifted them with an ability to scoff at  those who hibernate and instead, allow  themselves to freeze solid over  winter. They are members of a rather exclusive  club of vertebrate  animals that overwinter on dry land and survive the freezing  of their  body tissues. World-wide there are only a few species of vertebrates   that can tolerate freezing like this.  They may freeze and thaw several  times in  March before spring has truly arrived.
  
 The  sounds we hear coming from roadside ditches and vernal pools that form   in early spring belong to chorus frogs, resembling the sound of  fingernails  being dragged lengthwise down the teeth of a comb. For  them, life is a hustle as  roadside ditches and temporary ponds will  soon dry up. Their eggs hatch in as  few as three days, but it takes a  month for the tadpoles to develop into  froglets with lungs that will  enable them to survive without   benefit of  gills.
  
 Next,  it’s the spring peepers’ turn to dominate the evening air with their   sharp notes. As the water warms, thousands will break into a din, like  the sound  of distant sleigh bells. They may not measure more than an  inch in size, but can  produce more decibels of sound per pound than any  other living creature. Some  researchers claim that one spring peeper  call has the same decibel rating of an  airport runway. 
  
 There  is such a variety of instrumentation out there in the frog chorale it   actually becomes quite easy to identify them by voice alone. We all know  the  rattling snore of the leopard frog and they are no stranger to any  of us,  appearing everywhere, even on our lawns at certain times of the  year They are so  plentiful they actually become a hazard on highways  as hundreds of them hopping  from one side of the road to the other  become victims of traffic, creating a  slimy and dangerous surface upon  which to drive.
  
 Later  in the spring we will hear another frog, the “bong” note of the green   frog. It closely resembles someone plucking a banjo string, and we can  hear them  calling from nearly every cattail marsh, mixed in with the  other invisible  sounds that are produced nightly from the sedges and  cattails. 
  
 We  need to be patient before we hear the bass chorus of the bullfrog, as   they prefer much warmer temperatures before they are prompted to sing.   My  parents first identified these creatures for me when I was only a  few years old.  Since the only bull I could relate to was the Holstein  bull tethered out in the  pasture field, I had fabricated terrifying  images in my mind of something  extremely large and formidable crouched  low in the cattails, ready to attack if  I dared get too close. They are  our largest frog, reaching an incredible six  inches in size. Although  there have been some concerns about the overall  population of  bullfrogs, I find them somewhat cyclic, some years in low numbers,   other times producing a thunderous roar every evening, the chorus  starting low  and then exploding into a deafening crescendo that  resembles an approaching  thunderstorm. 
  
 There  is another frog that comes still later - the grey tree frog. First   timers hearing this sound are almost certain they have stumbled upon a   mysterious bird of some sort, or perhaps a raccoon, as the sounds are  similar.  Often they appear to originate from trees, and likely they do,  as this species’  feet have been thoughtfully provided with tiny  suction cups which enable them to  stick to just about anything. It is  not possible to appreciate its extremely  loud rattling trill, until a  tree frog has crawled up the side of the house and  has decided to call  all night right beside an open window. It was several days  before I  actually was able to locate the frog, but ended up leaving it there, so   intrigued was I by its call.
  
 The  long, wavering trill of the American toad will be on the scene too   before we know it. This is one of the more pleasant sounds we hear each  spring  and they often get so turned on during the mating season it is  possible to  approach calling individuals within a few inches. One of my  best photos was  taken with a macro lens at a conservation area pond  near Picton. The toad made  no effort to hide as I snapped its picture  at close range with a half dozen or  so kids not far from it engaged in a  noisy pond study. 
  
 One  of my favourites has always been the mink frog and it is a sound   synonymous with northern bogs and wetlands. Their range tends to be  north of  Highway 7 and I have heard choruses of them tapping away like a  hammer against  wood at Machesney Lake near Bon Echo, and near Madoc.   In recent years there  have been numerous reliable reports south of  Highway 7 indicating an expansion  of their breeding range. Pickerel  frogs with their distinctive low snore prefer  cooler streams can  sometimes be found with mink frogs but seem to be less common  south of  Highway 7.
  
 While  we won’t hear the bleating calls of the Fowler’s toad in our part of   Ontario, its absence is certainly more than made up by a spectacular  variety of  calls that will accent the wetland scene as we advance  cautiously into yet  another spring. 
  
 For more information on birding and nature and guided hikes, check out the  NatureStuff website at www.naturestuff.net 
  
 Terry Sprague lives in Prince Edward County and is self-employed as a  professional interpretive naturalist.