A Nature Ramble by Bike Along the New River Trail



With the conversion of abandoned railroad tracks to biking trails around the country, some of the best nature excursions can now be made by bicycle. This allows for a more rapid exploration of a wider variety of habitats than could be accomplished on foot. One of my favorite rail trails is the New River Trail State Park in Virginia which extends from Galax and Fries to Pulaski. One section which my wife and I bike frequently is from Gambetta to Byllesby Dam, a 10 mile round trip. On several recent visits we have been dazzled by the flowers and birds and amazed by changes in the river after floods. At the end of January water was flowing over the top of the dam threatening its failure, so the flashboards on the emergency bypass were removed to save the dam. My photo shows water now entering the flow way that bypasses the hydroelectric generating plant; the pool level behind the dam is greatly diminished revealing the river channel as it was before the dam was constructed. Such periodic demonstrations of the awesome power of water serve a useful purpose in revealing how puny humans really are in comparison with nature. They also show how riverside/riparian corridors are subject to episodic devastation that determines what few species can survive there in such abiotically stressful habitats. 

Spring flowers are considerably delayed this year in comparison with previous years, due apparently to cooler than normal temperatures. How this relates to global warming is a mystery to me. Four of the floral beauties that we enjoyed in late April are shown here. Wild bleeding-heart (not to be confused with the exotic garden plants) prefers rocky ledges along the river. Columbine is found in a similar habitat. Fire pink is more widely distributed and bright red tubular flowers have co-evolved for pollination by hummingbirds; note the long corolla tube when the flower is viewed from the side. This limits the number of animals that can reach the nectar and stickiness of the stalk inhibits the ability of insects to crawl up to the flower. The beautiful trillium Wake Robin is only able to reach a large size for flowering in areas where deer cannot eat it. These large plants were high up on a rocky ledge safely away from the hooved locusts. 

Even though frosts are still occurring in late April, butterflies are quite evident. This group of tiger swallowtails was gathered on a riverside mud bank drinking fluid from the soil. Such "puddling" behavior is generally due to presence of minerals such as sodium in the soil water. It is interesting how this becomes a social affair when a suitable site is found. The need for sodium is often acute for herbivores whose diet contains a lot of potassium but little sodium. 

Some amphibians are quite evident in spring time due to their calls. One frog with the loudest call, the bullfrog, is quiet now since it prefers warmer temperatures. But this female was sitting in a sunny shallow spot, presumably in an effort to warm up. Note that the ear drum is smaller than the eye- males have much larger ear drums, presumably the better to hear the other males with whom they are competing for pond-side territories. 

Of course the spring time is filled with a cacophony of wonderful bird songs. These appear to advertise the male on a territory, attract females, and deter other males. We find many of these songs very beautiful, especially that of the familiar and spectacularly colored male cardinal. His bright color also advertises his viability and ability to sire healthy offspring. Although the towhee is less brightly colored (it has a bright breast only) and its song is not as pleasing to human ears, I am sure it serves its purpose. And the purpose is of course reproduction. One of the first birds to begin laying and the last to stop producing clutches is the marvelous bluebird, which mysteriously lays sky-blue eggs inside a cavity where no one can see them! This clutch is in a box on our farm about one mile from the river. 

So get out there and enjoy the natural wonders of the spring. Try a bike ride, but do not fail to get off periodically and look at the flowers and the critters. High speed travel is incompatible with nature study, but a means of rapid transport can allow you to quickly find patchy occurrences of interesting creatures. 

Bill Dunson 
Englewood, FL, and Galax, VA