Kiley BriggsViews:
Turtles aren’t known for their speed, but despite that impediment, they sometimes make remarkable journeys over land. This is especially true when looking for a place to lay their eggs. When you see aquatic turtles crossing roads, the odds are they came from the nearest stream or wetland, but not necessarily. If there isn’t an obvious waterbody nearby, you might be left wondering where the heck the turtle came from.
I often ask myself the opposite question: where did the turtle go? Through our conservation work, I use radio telemetry to learn how different turtles use their habitat and I can usually only detect a turtle’s radio transmitter from half a mile away. Sometimes they travel a lot farther than that. When a turtle I know goes AWOL, I need to figure out where it went, ideally before it comes back on its own.
For example, the Texas Tortoise, a close relative to the much larger Gopher Tortoise, is something of a homebody, spending most of its life in an area 5-10 acres in size. For my master’s thesis at The University of Texas Rio Grande Valley, I used radio telemetry to study their habitat use. For the most part, they stayed put within small areas as expected, except for one. Unlike Gopher Tortoises, which usually lay their eggs at the mouth of their burrows, the Texas Tortoise might spread her eggs out across a wide area. Instead of putting all her eggs in one nest, she sometimes lays eggs individually in two or three spots outside of her normal home range.
When one of my thesis tortoises went missing, I spent the better part of two weeks driving around dangling a telemetry antenna out my car window looking for her signal. Just as I started to lose hope, I picked up the faintest signal from her transmitter, pulled my car over, and started walking in her direction figuring she close by. Hours later, after an arduous trek through dense thornscrub, parched mudflats, cactus thickets, and what were either heat mirages or hallucinations caused by dehydration, I found her… nearly 3 miles from where she started and 4 miles from my car. Days later she reversed course and headed back home. Long-distance egg-laying migrations, as it turns out, are not unheard of among Texas Tortoises.
Much more recently we had a female Wood Turtle go missing in the middle of nesting season. She had only been carrying a radio transmitter for a few days when we lost her signal, so we didn’t know much about her home range at that point. Her disappearance coincided with the hay harvest, which had us very concerned about her well-being. After a few hours driving around looking for her signal (again, with the telemetry receiver stuck out my car window), she turned up almost four miles away at another farm. We soon learned that this other farm is where she lives, and she had only traveled to the spot where we first found her to lay her eggs. One year later she made the same exact trip. Wood Turtles usually lay their eggs on a sand or gravel bar within their home range, but some choose to travel significant distances to lay their eggs elsewhere, especially if there isn’t any good nesting habitat where they live.
Blanding’s Turtles are notorious for their long-distance trips in search of good nest sites. They usually nest in open sandy clearings within a few hundred yards of a wetland. However, sometimes there isn’t any good nesting habitat close by, in which case they wander around until they find a good spot. Sometimes that means trekking across both land and water and laying their eggs upwards of a mile from where they started. After nesting, they head right back. In some cases, large numbers of Blanding’s Turtles will travel great distances to all lay eggs at the same high quality nest site.
These long-distance movements by nesting turtles underscore the need to protect and restore safe nesting habitat for the turtles close to their streams and wetlands. Roads pose one of the greatest and persistent threats to turtles. Sadly, the turtles most likely to be killed on roads are nesting females, which are the most important turtles in a population. It may take upwards of 20 years for females of some species to mature, and once they do, they will keep laying eggs almost every year for the rest of their life – even in to their 80s! So, when an adult female turtle’s life is extinguished prematurely, she is not easy to replace, and with her untimely death, decades worth of future nests and hatchlings are lost as well.
When turtles lack a good place to lay eggs they are more likely to cross roads, or even lay their eggs on the road, which is very risky. Reporting road crossing observations to state wildlife agencies can help biologists identify stretches of road where conservation projects are needed the most.
The saying, “if you build it, they will come” rings loud and true in the case of turtles. In cases where the lack of suitable nesting habitat is the reason for long-distance turtle movement, creating or restoring nesting habitat can go a long way to protecting the turtles. Conserving land and installing wildlife underpasses through roads are certainly worthwhile efforts that do really help, but such projects take time and can be prohibitively expensive. Building nesting habitat in safe settings between wetlands potential hazards (ideally 1000 feet away from roads) can intercept females as they search for a good place to nest. Turtles aren’t dummies, and they can recognize a better option when they see one.
And, importantly, when you do see a turtle crossing a road, the best course of action is almost always to move it across in whichever direction it was headed. Afterwards, please consider reporting your observation to your state wildlife agency, especially for rare species. Reports of turtles on roads are a great source of information that state biologists can use to help them determine where conservation projects are needed the most.
