Animating Landscape-level Movements by Wood Turtles

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It’s hard to imagine turtles traveling great distances over land during their lives, let alone in a single season. Surprisingly, it’s common for some turtle species to travel miles on land in just a few weeks, or even days. I covered this topic in writing in a recent blog post, but this month I am going to show you.

Last year, as part of a project aimed at identifying opportunities to prevent Wood Turtles from crossing a busy highway, we attached GPS transmitters to 15 turtles. The solar powered GPS units allowed us to collect a lot of data from each turtle without needing to find or handle them often. 

A solar-powered GPS attached to a Wood Turtle allows us to learn how the turtle moves across the landscape without needing to find and disturb the turtle during its travels.

Preliminary findings were not all that surprising. Some of the turtles, especially females, stuck mostly to smaller areas, hardly venturing more than a quarter mile all season. Others traveled miles, mostly over land, eventually returning to about where they started. Reading about Wood Turtles walking miles is not the same as seeing and really understanding it. By animating the GPS data to show movements across time, it is easier to understand how these turtles move about the landscape. I’ve given dozens of presentations and said countless times that Wood Turtles traveling miles is nothing unusual. The first time I showed some of these animations in such a presentation, however, I heard gasps. 

In the examples below, we doctored the aerial imagery to protect site locations. However, the general lay of the land and available habitats do not conceal how these turtles use the landscape. Take note of the scale bar in each of the videos below as the distance varies considerably. We’ll start with an example of a Wood Turtle that did not go very far.

This first female Wood Turtle did not travel more than 1000 feet from her overwintering site all season. Some of the places she frequented were seasonal, such as a mowed right-of-way under a guardrail where she foraged through much of the spring. Other habitats, such as one prominent gravel bar, she visited throughout the year.

Using radio telemetry, I lost track of the above female Wood Turtle for over two months in the summer. I eventually relocated her in the stream on the opposite side of the road from where she started. If I only had radio telemetry data from her, I might assume she crossed the highway while following the stream. However, her GPS data revealed a nearly 4-mile journey. She traveled through upland forest, across the highway nearly a mile from the bridge, back to the river, and then upstream toward where she started. Eventually, she settled down in an area where we had never encountered Wood Turtles before. 

As the crow flies, this male Wood Turtle traveled approximately two miles from his overwintering site. His total one-way travel was closer to 3.5 miles before he turned back toward his starting point. Most of his travels were over land, but he roughly followed a small tributary of the stream where he overwinters. 

The longest one-way trip from a turtle in this study so far was by the above young adult male. He traveled approximately four miles from start to finish. If we count his back-and-forth meanderings along the way, he walked nearly 6 miles. More surprising is that he did not return to the site where he overwintered the previous year. It is possible the entire area is within his established home range, but his movements may also represent a dispersal event. We’ll learn more next year.

The large-scale movements these Wood Turtles undertook make one thing abundantly clear. Wood Turtle conservation needs to be thought of on a landscape-level scale. While restoring habitat on any single property is a huge help, protecting populations of Wood Turtles long-term is most successful when efforts are targeted to high priority focal areas over time. Protecting “Property A” might be an essential step in the process, but that won’t be enough to ensure the future of Wood Turtles there unless other conservation efforts are done in other spots between properties B through Z.

That is why our Wood Turtle conservation program operates on a landscape-level scale. We are more than happy to give advice on how to protect and restore Wood Turtle habitat on any property, but 90% of our attention is directed to a handful of river valleys. By working with partners and rallying additional support for Wood Turtle conservation, we can help ensure the species has a bright future in the places most important to them.