Road mortality an increasing problem for local turtles

            It’s turtle nesting season in southern New England, which unfortunately means that many female turtles are likely to get crushed on roadways in the next few weeks as they trek to their preferred nesting location. It’s an issue that Lou Perrotti, director of conservation programs at Roger Williams Park Zoo, said is a growing problem caused primarily by increased development and habitat loss, which forces turtles to cross streets to reach their nesting habitat.

            “This is one of the major threats that face turtles and tortoise populations every year,” said Perrotti, who has seen dead turtles of several species on Rhode Island roads in the last two weeks. “A population can only take a hit of so many adult females before you lose the entire next generation.”

            Rhode Island is home to seven species of native turtles (excluding sea turtles) – painted, spotted, snapping, musk, wood, box and diamondback terrapin – and most of them lay their eggs in late May and early June.  Painted and snapping turtles are the state’s most common species, and they generally only travel about 100 yards to their nest sites. But that 100 yards can be perilous because of the road crossings it often requires.  Perrotti said the turtles typically seek out the same egg laying location each year – usually a site with well-drained soil on a southern exposure that’s close to their pond – so those that cross roads to get there must do so year after year.

            Unlike the movement of frogs and salamanders to their breeding ponds in March and early April, which occurs almost exclusively on rainy evenings, turtle migration to their nesting grounds can happen any time and in any weather, though Perrotti said that you’re likely to see more turtles during wet weather when wet soils make it easier for them to dig their nests in. So drivers should keep an eye out for turtles every time they climb into their vehicles in the coming weeks, especially when driving near wetlands.

            In 2015, University of Rhode Island student Elizabeth Shadle conducted a study of turtle mortality on roadways in Colonial National Historical Park in Virginia, where many of Rhode Island’s turtle species are also found. She discovered, rather unsurprisingly, that most turtles were killed on roads that were adjacent to wetlands compared to roads near upland habitat.
              "It may sound obvious, but it's important to collect the data," Shadle said. "It means that proximity to wetlands is an important predictor of roadkill mortality for aquatic turtle species. and it has implications for species-specific wildlife management."

But just because most roadkilled turtles are struck on roads through wetlands doesn’t mean drivers shouldn’t also be on the lookout for turtles when driving through upland areas this season. One of the region’s rarest turtle species, the box turtle, prefers woodlands, pastures and thickets over wetlands and is often killed by vehicles.

“Box turtles get whacked way more often than I would have thought,” Perrotti said. “They look like a big rock in the road, so you’d think drivers would swerve around them. How do you run over a box turtle unless you’re just not paying attention?”

            So what should you do if you encounter a turtle attempting to cross the road? Usually, Perrotti said, the best thing to do is to leave it alone. Picking it up and returning it to a nearby pond won’t solve the problem if the animal has yet to lay her eggs. She’ll just turn around and head back across the road.

            If a turtle is at risk of being struck by a vehicle, Perrotti suggests moving it to the side of the road in the direction it was heading. Just be extremely careful if the species involved is a snapping turtle, since they have powerful jaws and can inflict serious harm.

            And according to a fact sheet from the Rhode Island Department of Environmental Management, it is never advisable to remove a turtle from the road (or anywhere else) and take it to a completely new location, since individual turtles have a very specific home range that they occupy their entire lives.

“You may think you are bringing the turtle to paradise when you take it to your favorite brook or pond, but in reality you could be giving it a death sentence,” reads the fact sheet. “Not only is it possible that the turtle may not find suitable food and habitat in the new home, but many turtles will try to get back to the area they were moved from. In such instances, they may travel until they are exhausted or exposed to numerous additional threats, or they may cross several roads and get crushed anyway.”

 This article first appeared in EcoRI.org on June 2, 2016.