Fauna of the Week--American Toad
Imagine a thunderstorm in spring. "Toad Chokers," some are called. Afterward, puddles left in parking lots and ponds everywhere suddenly become the main attraction for toads no one knew were there. A front-row seat is deafening. Shoot, the cheap seats are deafening! One female, pursued by three or four males, can sound like one hundred. Check out this page on eNature and click "listen" for a small, tame sample. Then come back! Really, go play the track. I had to play it three or four times it was so much fun.
[Photo: female toad full of eggs heads to a small pond to unload, so to speak.]
While eggs laid in puddles are unlikely to survive, a backyard water feature can do the job nicely with very little water volume. A forceful waterfall won't do the job--you need a kind of still area where the eggs and tadpoles can mature. It can take a month or more for those eggs to develop into tadpoles. If the water dries up, the whole 4000-8000 eggs (that's per female toad) will perish. If water levels are kept relatively consistent, you can add a huge pest control population to your home habitat. (Don't worry. You will NOT suddenly have 8000 toads in your yard.) During this early development, young toads are herbivores. Only after completing the transformation to true toad-dom do they become carnivores and an awesome force for the good of your garden.
American Toads have been able to inhabit suburban areas partly because of the diversity of their diet--they eat just about any insect around and also eat earthworms and slugs (my favorite reason for having them around...I have slug issues!). They need the cover of brushy areas, logs or stones to hide under and a fairly permanent water source for success in breeding and early development. They do hibernate in winter, digging themselves into the soil--preferably under a rock or log. They will take cover under man-made structures as well, but you are far more likely to have success using logs or stones than treated lumber.
Which brings me to my next point. Species like the American Toad, which spend time in water and on land are greatly impacted by the use of pesticides and herbicides. On a simple level, if there are no insects (pests), there is no dinner for toads. But more importantly, the use of these compounds has lasting impact on our soils and our water supply--making both soil and water toxic to toads and the creatures they consume. It might seem strange that an herbicide like RoundUp can hurt toads--after all, they don't eat weeds as adults. But check out this nicely concise summary of the research on this popular garden chemical at Garden Guides. More than a little scary.
So my final point--toads are one of our indicator species. They "indicate" when there is a problem by not being present. Chemicals that build up in soil kill off the microorganisms that feed larger organisms that we can see with the naked eye. Enough chemical use and you can kill the larger organisms, as well. When you dig a hole in your yard and don't find worms or other soil insects, there is a problem. If you can dig a critter-less hole, it may not even be safe for you to grow vegetables--because its not just the critters that absorb all those chemicals. They just do it faster.
NOTE: American Toads are not going to kill your dog.
Yes, they have mild toxins that taste nasty to discourage predators--if a dog were to eat the toad he might get a little sick to the stomach. You do not have to fear for the life of your dog. However, there is a giant toad, the marine toad, that is toxic. Please note that this toxic toad is NOT NATIVE to the US.