Bufo houstonensis: one would think that the biology of an endangered species would be known well, especially since it’s remaining range is an easy drive from two major research universities, Texas A & M and, of course, the University of Texas. But surprisingly little is known about the species. The most systematic work on its ecology goes back to an important paper by a University of Texas colleague, David Hillis, and several of his collaborators over twenty years ago . Lately, Michael Forstner at Texas State University (San Marcos) has been doing some surveys, mainly to make sure that development and other habitat change does not drive the species to extinction. Everyone knows that it thrives in the sandy soils of Lost Pines but no one is sure why.
The Houston Toad was not even recognized as a distinct species until the 1950s. The 1984 recovery plan designed by the Houston Toad Recovery Team to comply with the Endangered Species Act, describes the few details that are known about the story of its “discovery” with a mixture of wonderful dryness and strange excitement (for instance, by calling the call of the toad “beautiful”):
“In the late 1940s there were several active amateur herpetologists in the vicinity of Houston, Texas. Notable among these enthusiasts was the airplane mechanic John C. Wottring from East Haven on the south side of the city. During his nighttime herpetological field trips in the semi-rural area around his residence, Wottring came upon a number of small toads with a beautiful mating call which sounded like the tinkling of a small bell. Other amateur herpetologists (e.g., Werner Gottech, Walter J. Greer) and Wottring collected the toad at additional localities in southeastern Texas. However, the taxonomic identity of the toad remained a mystery. Consequently, Wottring continued to study the habits of the toad, and he recorded and sonographically analyzed the toad’s mating call. Interestingly, Wottring was one of the earliest persons, (perhaps the first), to employ this technique with salientians. In subsequent years this approach became widely adopted for systematic and behavioral studies. Wottring showed the specimens of the toads and played recordings of its mating call to the famous Albert Hazen Wright of Cornell (who with his wife Anna authored ‘Amphibians of Texas’ in 1938) and other professional herpetologists. None of these persons was sure of the identity of the toad, but a relationship to the American toad (Bufo americanus) was suspected. When Ottys Sanders of Dallas saw the toad he thought it was a new species and he formally described it as Bufo houstonensis in 1953. In recognition of Wottring’s substantial assistance, he indicated that the common name for the species should be The Wottring toad.”
It is unfortunate that Sanders’ suggestion has not been taken. Wottring deserves some explicit credit for his role. Ironically, we call the toad after a city which, in its greed for development, wiped out all habitat for it in its vicinity. The Houston toad is no longer found in or around Houston. Its major stronghold is in Bastrop county.
We hope to adopt the toad as a special project of our own. I have always liked anurans, and the Houston toad is particularly intriguing because it is an unknown species in our midst. This will be a long-term project. For this year, though, we’ll restrict our attention to the Stengl Biological Station and try to carry out a proper census of the population there. It is a mere 208 acres, and there are very few ponds, ephemeral or otherwise. Visually these toads are different enough from other sympatric specie that there isn’t much scope for confusion. They also have a shrill mating call that can apparently be heard some eighth of a mile away. The call consists of a long, high-pitched trill (range, 14 -36 pulses per second; average, 25 pulses per second), with the pitch being significantly higher than that of the American Toad (Bufo americanus) and easy to distinguish from that of any sympatric anuran. In principle, it shouldn’t be difficult to carry out the survey, at least for the males. You go out for a few nights in close succession, inspect each pond, decide whether the toads are present from the calls you hear, shine a bright flashlight for a few minutes, and count all the individuals you see. The light is not supposed to bother the animals. You report the highest population you find in any single night, obviously an underestimate, but it is usually better to err on the side of caution for an endangered species Forstner reports seeing many more males than females, but that could be a result of not finding all the females. Tagging is probably easy, but getting the permissions required to work on an endangered species is probably a nightmare. Estimating female populations is an entirely difficult matter.
Studying the toad should be fun and several students have expressed enthusiasm for the project. It’ll be interesting to see how much of that enthusiasm survives the first muddy night in the ponds and ditches of Stengl. Conservation and ecology are often more interesting from the perspective of a comfortable chair than in the field. But it could well be that some of these students are of that rare breed that doesn’t always like a roof over their heads. In any case, Texas needs more residents working on Texas—at least that’s how it seems when you teach at the University of Texas at Austin. There are potential problems. The toads have a contracted mating cycle, sometimes going through their reproductive business in a few weeks. So we have to be ready to go out as soon as Phil Schappert says that they are out. (Schappert lives at the station. We, unfortunately, don’t.) The real trouble, though, is that it’s far from clear that the toads will emerge this year, at least at Stengl. February and March constitute its favorite breeding season though they have been knnown to breed much later. Folk wisdom suggests that they emerge when conditions are sufficiently humid and we have warm evenings. Well, January and early February were warm but we’re in the middle of the worst drought in almost a decade. It’s been a little wetter lately (at least it rained on Saturday) but it’s fairly cold now, at least by the standards of this winter. There has been no sign of the toad at Stengl and there have been years when it hasn’t been seen there. With luck it won’t be such a year. Meanwhile we’re waiting for the Houston Toad.
 Hillis, D., Hillis, A. M., and Martin, R. F. 1984. Reproductive Ecology and Hybridization of the Endangered Houston Toad (Bufo hustonensis). Journal of Herpetology 18: 56 -71.