While many of us are enjoying these cool, winter evenings indoors in front of the TV with our favorite snack, Houston toad researchers are bundling up, grabbing a thermos of coffee and hitting the road to find the elusive Houston toad! After the first heavy rain of the year, often near the end of January, Houston toads are hitting the ponds to look for mates. The Houston toad spends the majority of the year in shallow burrows to escape the extreme Texas temperatures (a process called estivation); therefore the best opportunity to find and count toads is during their breeding season when they are out and about.
Though some toad biologists slip on a pair of rubber boots and put on a headlamp to look for Houston toads using sight, most researchers search for toads using sound. Sound? How does that work? The Houston toad males have a very distinctive advertisement call, which is the call that they use to tell female toads “Hey, lady! Check me out! I’m over here!” In fact, all species of frogs and toads have a distinctive call that they use to get the attention of the opposite sex. Interestingly, it is not just the males that do the calling. In some species, including another local frog species called the gray tree frog (Hyla versicolor), the females will both call and counter-call (which means to call back) to the males. To hear a Houston toad call, check out the following link: http://www.californiaherps.com/noncal/misc/miscfrogs/pages/a.houstonensis.sounds.html
To find calling toads, researchers set out in their cars after dark to literally “listen” for Houston toads. The areas that are visited have been previously identified as suitable habitat for the Houston toad, or are locations where Houston toads were either found or heard in the past. The surveys follow a very systematic pattern with dozens of stops, and they often take hours to complete. This year, for the first time in several years, five Houston toad counties are being surveyed at once lead by research teams from Texas State University and USFWS. Fingers crossed that we’re going to find some wild toads!
Another way that researchers find wild Houston toads is through the use of a recording device called a SongMeter. A SongMeter is specifically designed to detect the auditory calls of wild animals. To detect Houston toads, SongMeters are placed in trees near ponds and are programmed to record sounds during the course of the night. These devices can record two weeks’ worth of sound data! A software program is then used to find the particular waveform that correlates to the Houston toad call. Of course, every Houston toad “hit” found by the software program has to be verified by human ears, which requires hours of listening time.
So over the next couple of months while you’re enjoying your favorite evening TV show, take a moment to think about the field researchers braving the chilly, wet Texas nights on the hunt for the Houston toad. Each toad found (or heard) tells us more about the health of the wild population and gives us another critical piece of information concerning the natural history of this rare species. Good luck toad folks and Godspeed!