I Killed the Bufo (Via Herp Digest)

I Killed the Bufo, by Mark Derr, 7/23/11
Mark Derr is the author of the forthcoming "How the Dog Became the Dog: From Wolves to Our Best Friends."

Miami Beach
I CONFESS. On a recent night, a very dark night, around midnight, I killed a Bufo marinus, commonly known as a cane toad or giant toad. The Bufo had established its domain in our pond several months earlier and swaggered about the backyard at night as if it owned the place.

Like our house, the pond dates to 1925. Made of concrete, it is four feet in diameter and two feet deep, with two inches of muck. Presiding over it is a two-foot-tall plaster cherub jury-rigged fountain that was already old when we moved in 20 years ago. The pond then was a stagnant breeding ground for mosquitoes and algae. Today, it is home to two thriving plants - a lobelia native to the Everglades and a colocasia, an exotic from Southeast Asia. The pond is algae-free and stocked with gambusia, the local minnows that are mosquito predators - hence their common name, mosquito fish.

I have kept the pond more or less functioning since we moved in, and I have no desire to see it colonized by toads the size of soccer balls that secrete toxin from glands in the back of their heads strong enough to kill cats and small or infirm dogs. I feared that our aged kelpie, Kate, would stumble upon the Bufo invader and meet her demise.

I am hardly an ecological purist who would remove every exotic animal as soon as it appeared in an ecosystem not its own, primarily because I figure that at one point or another all of us on this planet have been "invasive species" - or shall I say, pilgrims in search of a better home. Most creatures who visit South Florida, especially when coming from a cold, gray climate or an oppressive political atmosphere, never want to leave. They congregate here and sometimes reproduce so profligately that they are impossible to contain, much less to remove.

In the years I have kept it, the pond has had a mixed record on exotics. For several years, it harbored a visiting African lungfish that trained me to feed it whenever it surfaced with its mouth open. The lungfish prospered until its owner took it away, but as a rule nonnative fish and plants have faltered.
Since the 1930s, people have brought Bufos into Florida, usually to serve as biological pest controls in sugar country around Lake Okeechobee. but the current Bufo population in South Florida appears descended from a group that escaped from a wildlife dealer at the Miami airport in 1955. Similar releases in Australia to control pests in sugar cane fields have created an ecological nightmare that could be titled "Invasion of the Cane Toads."

Still, the notion that the Bufo had to be removed remained abstract, something I should do but could delay as long as I was vigilant with Kate. Since I take no pleasure in killing, that studied ambiguity suited me. I even passed up several opportunities to dispatch it. I hoped it would voluntarily decamp, but I knew it was growing large enough and brazen enough to threaten our dog, who often visited the pond.

I knew I had to act, though, when I learned that several neighborhood dogs had died from Bufotoxin.
Reportedly, the humane way to kill a Bufo is to apply a painkiller and then freeze it in a plastic bag, but I did not want to attempt to catch it, because Parkinson's disease has skewed my balance and dulled my reflexes. I had other plans. After failing to find a gig - a multi-tined spear for hunting fish and frogs - I manufactured my own using oversize deep-sea fishing hooks. I bided my time until I found the Bufo squatting on an exposed piece of limestone in the middle of the pond. I speared it with my gig at the base of its head and unceremoniously dumped it into a garbage bag I then sealed.

I acted to protect our dog without a thought toward other consequences. But within a week of the Bufo's death, I began to notice changes in and around the pond. Young and old gambusia appeared in significant numbers, swimming freely and openly. I am no expert on Bufo behavior, but this one had an ability to knock down plants growing around its chosen resting spots. Once this Bufo was removed, the pond plants grew lush. Anole lizards, whose absence I had silently noted for some time, became everywhere apparent, and I have begun to hear tree frogs again, as well. Even better, the mosquito population collapsed, leading me to conclude that although the Bufo did not appear to eat the mosquito-loving gambusia, its physical presence had somehow intimidated them and forced them into hiding.

I cannot claim to have restored "balance" to our backyard ecosystem. I am even uncertain how to define balance for a fenced area that is dominated by a swimming pool and a mango tree that feeds us and numerous other animals.

There might be other plausible explanations for what I see, but I can say the available evidence indicates that removing an imperialist bully has improved the health of our pond and yard, not to mention our comfort.