Kiley BriggsViews:
Wood Turtles have a reputation for being creatures of habit. Adults often return to the same spots year after year to feed, shelter, and nest—something known as site fidelity. As with any species, it is important to realize that behavior norms are not the same as strict rules. A study I began working on a few years ago makes that abundantly clear. One turtle in particular, “One-eye”, is a perfect example of one that broke expected species norms.
I first met One-eye, a male, perhaps in his 30s, in the spring of 2022 while he was basking in vegetation near his stream. He does technically have two eyes, but his right eye is atrophied, recessed inside his skull, and appears to be functionless. No signs of infection, though, and the condition hasn’t changed in several years.
I placed a GPS tracker on him the following spring to see how he and other Wood Turtles interact with several bridges and culverts being replaced. The old structures block aquatic animals from moving upstream and force turtles to either turn around or cross a busy highway. The new bridges will be more wildlife-friendly and include some additional turtle accommodations. So far, One-eye hasn’t gone anywhere near a bridge, but he has covered some serious distance, and crossed the highway a few times.
The first season tracking him, he stayed close to his stream, spent most of his time on land in the forest, and slowly traveled about a mile upstream before returning to where he started. This is typical of male Wood Turtles, which tend to spend most of their time close to their streams and travel greater distances up and down river valleys compared to females. A mile is nothing unusual.
One perk of his impaired vision is that, if I approach quietly, from downwind, and on his blind side, I can watch him forage in leaf litter, scratching for worms, undisturbed by my presence. Eventually, he always catches a whiff of me and pans his head around before finally spotting me and ducking into his shell.
In year-two of tracking him, One-eye surprised me. Instead of foraging in a valley forest, he spent weeks eating in the mowed roadside under a guardrail and even crossed the highway—far from any bridge—to explore steep uplands nearly 1,000 feet from his stream. While his time spent foraging under a guardrail made me quite nervous, this observation (and that of a few other turtles) may help influence updates to roadside mowing practices in the state. In total, One-eye ended up about a mile from where he started, and just like the year before, he eventually turned around and went back to where he started. It’s not that unusual for a Wood Turtle to go different places from one year to the next, but it’s not what I predicted.
In year-three, this past spring, One-eye started off about the same as the previous year. Finding him once again foraging in the mowed right-of-way gave me serious angst. And, with only one eye, if he chose to cross the road again, he’d be blind to traffic on one side (not that having both eyes would really help). So, you can understand my concerns when he went missing after last being seen within 10 feet of the highway. It didn’t take me too long to find him; all I had to do was drive up and down the highway with a roof-mounted telemetry antenna in search of his signal. Thankfully, he wasn’t a flattened piece of turtle jerky on the side of the road. He was alive and well, two miles upstream from where he started.
Two miles still isn’t remarkable for a Wood Turtle; I was just a little surprised One-eye would go so far after two years in a row of going almost exactly one mile. But then he kept going. Next time I saw him, he had gone another mile upstream and was in a meadow behind some guy’s house. At mile-three, he had run out of river. During his journey, the stream he started in transitioned into headwater wetlands, and then ended. Surely, he would turn around soon.
By mid-July he had covered yet another half mile of ground and was in the headwater wetlands of the next major watershed. A few weeks later, another half mile up the valley, and he was in the next named stream. I started to wonder if he was going to turn around. It was still mid-summer, so he had plenty of time, but I doubted whether he would go back. Ultimately, he chose to overwinter under a submerged root mass in that new watershed, roughly four miles from where he started, and that is where he still rests today.
Questions are nagging at me. I’ve seen Wood Turtles travel much greater distances, and I’ve seen them jump watersheds before, but those were young males, which I think are more prone to dispersal. Has One-eye abandoned his old territory and dispersed to a new site? Has he been to this new site before? Maybe this is where he started earlier in his life and the previous few years were the exception? Or does he bounce back and forth sometimes and both sites are part of his permanent home range? Some Wood Turtles might also be more transient, almost always on the move in search of new mates. I previously thought, that when Wood Turtles disperse to new locations, that they would usually do so by following a single waterway or moving up or downstream into different tributaries. But now, with One-eye’s journey, I’ve seen two Wood Turtles jump watersheds by essentially running out of stream and then walking overland to the next river. Following river channels may be more common, but this terrestrial dispersal is starting to feel like a more normal thing that Wood Turtles do sometimes.
I have no idea what One-eye’s next move is. Will he stay? Will he go back? Or will he keep wandering in the same direction? I’m just really curious to find out. Regardless of what he decides to do next, One-eye demonstrates an important point very well: Wood Turtles are landscape-level animals, and the long-term survival of their populations depend on landscape-level conservation efforts.
Read more about Wood Turtles, one of our priority species.
