Trrrlrrrlrrrlrrrrl! Trrrlrrrlrrrlrrrrl! It’s the sound my wife and I have been anticipating for weeks breaking the silence of the night. Toads! The small depression I maintain in our yard just for this night—our toad pond—is alive with American toads (Anaxyrus americanus, formerly Bufo americanus). The male singers are busy calling in the larger females, each of which is replete with hundreds of eggs. Fresh from his overwintering hideaway, each male does his best to sing louder and deeper than his competitors. Female toads, like the females of most species, are particular about which male they will mate with, and they prefer the largest, most fit individuals at the pond. After making her choice, all a female needs to do is hop near the winner, and he will do the rest.
Toads and other amphibians employ external fertilization to start a new generation. Rather than depositing sperm within a female, a male toad coats her eggs with his sperm after she has laid them. To ensure that he (not some other male) fathers the eggs, the male must be in the optimal position when the eggs are being laid: on the female’s back. As soon as he is permitted, the male will leap onto the female and hug her in a behavior called amplexus. He needs to hang on tightly, because other males will try, sometimes violently, to dislodge him. And there he stays, sometimes for hours, waiting to fertilize the eggs that the female lays in long, gelatinous strings. The mating game continues for a few days, as new females arrive, seek out a mate, and lay their own eggs.
By week’s end, the pond contains many thousands of eggs that soon transform into wriggling black pollywogs (also called tadpoles) and, after about six weeks, into tiny terrestrial toads.
Other North American species of toads enact similar courting rituals. The song of Fowler’s toad (Anaxyrus fowleri) can be heard in May and June through much of the eastern United States, while the red-spotted toad (Anaxyrus punctatus) sings in spring from Texas to Southern California.
Protect Your Toads
Encourage toads to live and breed in your yard by digging a shallow pond for them. Create a no-mow zone near the pond, and restrict mowing elsewhere to the midday hours, when toads are sheltering from the sun.
Pollywogs eat algae that grows on the surface of submerged leaf litter, so it is important not to clean out all of the twigs, leaves, and other bits of organic material that have accumulated in your pond through fall and winter. Please, no fish in the toad pond: They will eat every last pollywog.
A Final Tip: Be sure to cover your window wells. Each year, millions of toads perish after jumping into window wells they can’t escape from.
The best way to hear the springtime serenade of American toads is to seek them out in their natural habitat. You can also eavesdrop online, at the website of Cornell University’s Macaulay Library. Find an audio clip at macaulaylibrary.org .
Douglas W. Tallamy is a professor at the University of Delaware and the author of Bringing Nature Home.