|Look Alert: Turtles Crossing
by Marc Killingstad
Of all turtles the Eastern box turtle is among the most familiar and, many feel, the most attractive. They are typically four to six inches long with a high, domed shell that is usually dark brown with orange or reddish blotches of various size and shape that form an eye-catching pattern.
Only recently, as box turtle populations are vanishing, have biologists begun to understand the delicate population dynamics of this species. One study concluded that the loss by traffic, pet collection and so on of just one adult box turtle from a population each year or two will doom that population to eradication in the not too distant future. Thats what a 1995 study at the Patuxent Wildlife Research Center meant by the words slow recovery from losses may indicate that populations of the species would respond poorly to exploitation. Essentially, too few young are growing up among their elders to replace the losses.
North American box turtles are listed as a threatened species by the Convention of International Trade in Endangered Species of Fauna and Flora. Thats not as bad as endangered, but they are considered a species of special concern in many states. For example, they are listed as nongame-protected in Virginia by the Department of Game and Inland Fisheries, which says that because of the numbers killed on highways each year and because of fragmentation of populations in urban and agricultural areas, we should be concerned about the loss of reproductive adults in isolated woodlots. Losses of even a few adult individuals could cause extirpation of local populations, especially if these populations are small to begin with.
Box turtles produce small clutches of only three or four eggs a year. Temperature and rainfall extremes, fungus and predators frequently destroy the eggs. Even when an egg does hatch, the hatchling has a slim chance of surviving weather, predators and other hazards to reach adulthood. In addition, it takes years to develop the stronger, protective adult shell and years of habitat familiarity to attain some relative safety.
On the other hand, a female who survives her first several years to reach reproductive maturity can produce a few hundred eggs during her lifetime, which can reach from 75 to 100 years. Yet from this lifetime of egg production, only two or three hatchlings may reach adulthood and replace aged adults, sustaining the population.
The impact on a population of losing that slow trickle of eggs from one adult usually goes unrecognized during a human lifetime. But declines have been confirmed by many scientific studies that have followed a specific box turtle population with radiotransmitters over long periods.
The decline began long ago, as the turtles ancestral habitats were either destroyed or cut off by roadways and development. Such farming operations as cutting hay and lawn mowing claim their share of box turtles. Deaths along their customary routes to food, nest and hibernation sites have increased dramatically as their home territories continue to be invaded by vehicles and new construction.
Over four days in the last week of May, I came across a dozen box turtles crushed by cars on my way to and from work. In one day alone, I saw six dead and witnessed the death of two more. I realize, having grown up in a rural area, that wildlife frequently is hit and killed by automobiles. Its often an unavoidable occurrence.
For the most part, though, box turtles are found either on or near the shoulder sunning themselves early in the morning, or they are easily spotted while crossing the road. In other words, they can be avoided. All of which leads me to believe that people either are inattentive drivers or, even worse, hitting turtles intentionally.
If you are lucky enough to see a box turtle wandering the woods or on your property, please leave it untouched. Simply enjoy them and realize that nowadays fewer and fewer people have such an opportunity. If you find one crossing a road, simply help it to the side toward which its headed. Many researchers feel that moving them to a distant site simply dooms the animal to begin searching for its former home, multiplying its likelihood of encountering highways and other hazards. Their protective shell unfortunately does not allow them to survive the impact of an automobile.
Most important, please exercise caution when driving along rural, wooded areas particularly in the mornings, evenings and after rainstorms. By this simple act, you will contribute greatly to the future of this remarkable species.
Human activities pose the greatest threat to box turtle survival. Protecting existing turtle colonies from people and their machines is the best hope for the turtles future in the wild. Give these wonderful creatures a much-deserved break.
Killingstad, of Harwood, is an environmental scientist recently arrived in Chesapeake Country from the Blue Ridge. He volunteers in wildlife rehabilitation.