Over the past few months, The Mountaineer has heard reports of unusually large numbers of toads turning up on farms in the prairie west of town. Those who have shared information with us have joked that the unusual phenomena resembles one of the plagues in the book of Exodus. I began looking into the matter, thinking it might be an interesting bit of local ecological news, and learned that a similar population spike took place in town a little over a decade ago. Digging into the last century of Mountaineer back issues revealed that the occasional "plague of toads" isn't all that unusual. I came across more than a few examples of the weird phenomena.
I reached out to a herpetologist (a zoologist that studies reptiles and amphibians) with photos of our local toads. He identified our abundant amphibians as Great Plains Toads (Anaxyrus Cognatus) and explained that toad populations are heavily impacted by the presence of water. High presence of water during reproductive and developmental stages can cause the populations to increase. Coupling that with the presence of larger than normal food supplies can result in significant population growth. Predator-prey relationships tend to spike in waves, where prey populations grow, which results in a growth in predator populations as the abundance of food makes it easier for them to survive and reproduce. With the increase in predators, the prey population decreases, and then so does the predator population. My herpetologist friend pointed out that this season could represent a high point in the predator population and that a combination of plenty of water, warm weather, and lots of food can result in population explosions.
The Great Plains Toad reproduces after heavy rains throughout spring and summer in shallow
water, including pools of water left after rainstorms. Females lay as many as 20,000 eggs at a time, which typically hatch in 2 days. It takes 6 to 7 weeks for metamorphosis to take place and produce an adult toad. The toads burrow underground and remain there during the day, typically coming out at night. During periods of low moisture and droughts, Great Plains Toads remain dormant in their burrows. Some years, they don't reproduce at all.
One unusual thing about this year's population growth is the toads visibility during the daytime hours. The guidebooks indicate that a larger than normal presence during the day is typically the result of a large amount of moisture being present. The wet spring, cooler than normal summer, and several recent rain spells seem to be a reasonable culprit. The rainfall probably landed on exactly the right days to aid in their reproduction.
Ideally, the large number of toads will also be associated with a lower than normal pest population because the toads are eating something. The Great Plains Toad is sometimes called the "Farmer's Friend" because its diet consists largely of crop destroying insects, including sawflies, cutworms, and various breeds of beetles. They also eat flies, wasps, and mosquitoes, which certainly makes them a friend of mine.
As with the explosion in the grasshopper population over the last few years, the toad population seems to be growing as a result of the perfect storm of weather and the presence of food. Fortunately, this round of Biblical plague is quite beneficial to farmers.
The toads are poisonous to dogs, though according to the material I have read, the effect is mainly unpleasant and most dogs get rid of the toxins by drooling them out. My research further found that the effects of the poison usually passes in about 30 minutes.
