TAKE A WALK IN A SOUTHERN STREAM

by Whit Gibbons

September 16, 2002

When I saw the bullfrog sitting up in the bush with all the flowers, I knew the trip had been worthwhile. That's the great thing about getting out in the woods in autumn before the cold spells hit. Animals and plants abound, and you never know what you might see.

I was with John Jensen, the herpetologist with Georgia's Department of Natural Resources, and Kurt Buhlmann, the turtle specialist with Conservation International. Since all of us were overdue for a field trip, we decided to take an excursion out to a coastal plain swamp in South Carolina. John wanted to catch a rainbow snake, so that became our mission. Searching for the rare and beautiful rainbow snake is always a good excuse for an outing. When we saw the bullfrog we were wading shin deep in a clear, woodland stream, a tributary into the swamp. We were not really lost, I explained, because I was sure this particular stream came out near a dam where it flowed over a spillway. An hour or so before, I had admitted that I was not sure how far upstream the dam was.

Nonetheless, trekking along in a crystal clear, sandy-bottomed stream on an almost-cool autumn day can be delightful and make you glad you got out of the office. Numerous plants bloom in the fall, and most streamsides in the South are adorned with shrubs and solitary plants with sweet-smelling flowers. We saw bright red cardinal flowers along the stream's swampy margins. Shrubs with perfumy cream-colored flowers were on the higher banks. Yellow composites of different sorts were in the drier areas. My glance toward one of the flowering shrubs brought the amazing sight of the bullfrog.

This was the first time any of us, all experienced herpetologists, had ever seen a bullfrog sit high in a bush, fully five feet above the ground, but there it was. We all knew that just because we had never seen such a thing before did not mean it was not a common event. And being ecologists, we assumed there must be an explanation. Within minutes, what we decided was part of the explanation flew into view.

I wish I could say we actually saw the event we assume occurs when bullfrogs perch in bushes (something, you will remember, that none of us had ever heard of or seen). However, we can speculate based on circumstantial evidence. Let me show you how the science of ecology sometimes works.

As we looked at the enormous bullfrog (probably almost a foot long when stretched out) perched majestically in the top of the bush, Kurt pointed out a cardinal flower growing nearby. I commented that cardinal flowers are one of the last natural feeding sources for hummingbirds that migrate south during this season. As I said this, Kurt pointed above the bush and said, "and there one is." A hummingbird zipped into view above the flowering bush, hovered for a moment to watch the three of us standing in the stream, and disappeared. John then noted that "maybe the bullfrog is sitting in wait for a hummingbird meal."

We did not see the bullfrog eat a hummingbird, but I have no doubt that it had climbed into the bush to sit amid a smorgasbord of birds and insect prey. I looked upstream to the next bush like that one and noticed it was covered with butterflies, as this bush had probably been before we three humans blundered onto the scene. The bullfrog was simply doing what frogs and other animals spend most of their time doing-looking for something to eat. And bullfrogs have been documented to eat everything from birds to small snakes to baby alligators.

We never did see a rainbow snake on that excursion. But sighting the bullfrog was its own reward. And it reminded us that the unusual and unexpected may be encountered in nature at any time. You don't have to get lost in a stream; you just have to walk outside and look around.



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