New effort aims to help threatened wood turtles in Minnesota, Wisconsin
Wood and wire cages, placed in just the right spots, help keep predators out of wood turtle nests.
DULUTH — Sometimes, if you want to help a threatened species recover, you have to do more than count them. Sometimes you have to dig deep and help them fight off their enemies.
Take the wood turtle in the Northland. A threatened species in Minnesota and Wisconsin now being considered for federal protections under the Endangered Species Act, wood turtles have been declining in number for years.
"Some populations are dominated by older adult turtles with little evidence of juvenile recruitment," Minnesota's 2020 conservation plan for wood turtles notes. "Overall, populations are generally small, isolated and at risk for extirpation."
June is an especially deadly time for all turtles, with females on the move to nest.
“The nesting season is a really tough time to be a turtle mother. Many are removed from the population by car collisions on roads, while some protected species are illegally taken from the wild and sold in the illegal pet trade,” said Andrew Badje, Wisconsin Department of Natural Resources conservation biologist.
Because it can take some female turtles 12-20 years before they can reproduce, saving even one turtle can make a difference in local turtle populations for some troubled species like wood and Blanding's turtles.
Wood turtles were once common in most of eastern Minnesota, from St. Louis County in the north to the Iowa border, and across Wisconsin. They thrived in areas with sandy shorelines along waters with plenty of forest nearby. But wood turtles spend more time on land than most other Minnesota turtles, and that makes them more vulnerable to humans.
Adult female wood turtles spend a good portion of their summer and fall on land eating berries, worms, mushrooms and insects, sometimes miles from their favorite river.
They face a barrage of problems. Because they like to lay their eggs in sandy or gravelly soil near water, their nests are prone to floods, which are increasing due to climate change. The sand bars and beaches on waterways also are where people like to build cabins and play.
“The kind of places where people love to recreate happens to be just where the wood turtles plan to make their nest,’’ said Gaea Crozier, nongame species specialist for the Minnesota Department of Natural Resources.
Roadways also are an issue not just because they cross wood turtle migration paths, but because the sandy, gravelly soils along rural roads would be great places to lay eggs — if cars and trucks weren’t driving past. Turtles also are drawn to sand and gravel pits, where truck traffic can be a death sentence.
But it’s more than just a people problem. Even if turtles find a place away from people and trucks, predators are scooping up and eating their eggs at a rate that’s unsustainable for wood turtles to survive. One study found fewer than 10% of wood turtle nests are successful, with eggs actually hatching. Ravens, foxes, raccoons and skunks all are taking their toll. (Many of those predators seem to increase in number when people move into an area.)
And in Northeastern Minnesota, there’s been a surprise predator: badgers. One study using trail cameras found badgers ate 85% of the wood turtle nests that had been destroyed.
And not only are there fewer wood turtles making it to adulthood, but more adult turtles are dying, and researchers aren't sure why. Surveys conducted from 2016 to 2018 found a "substantial decrease in the number of individuals at eight monitoring sites coinciding with a large number of dead turtles of unknown cause found at the same sites."
The estimated number of wood turtles at those eight sights in eastern Minnesota plummeted from 247 in 2016 to just 88 by 2018. It’s still unknown what caused the sudden die-off of adult turtles.
Nesting help project
The good news is that people can help wood turtles, too. Electric fencing around wood turtle nests raised the success rate to nearly 50%. But electric fencing is expensive and time consuming, and needs to be adjusted often.
Enter a nest protection box or cage that Wisconsin biologists developed and used to successfully protect wood turtle nests. The cages are set down into the sand, but above the usual high-water mark, along sandy rivers. The cage has a 4-inch wide opening that allows adult female wood turtles to enter, but which will keep nearly all major predators out.
The U.S. Fish and Wildlife Service awarded a $1 million grant to wood turtle restoration efforts in Minnesota, Wisconsin, Iowa and Michigan, with each state getting $250,000. Crozier said Minnesota will use its money — with added help from the state’s Nongame Wildlife Program — to conduct long-term, extensive monitoring of turtle numbers along key rivers in the Northland, but also to build and install nest protection devices to increase turtle numbers.
“That's the goal, to see if we can actually make a difference in the local populations, to see more turtles,’’ Crozier said.
The effort is similar in Wisconsin. Badje said nest protection devices are being placed near areas where wood turtles have been frequently killed on roadways this time of year, indicating their nests are probably close by. If the devices help keep the females from laying eggs near roads, more turtles should survive, he noted.
Sometimes, even protected nests don’t do well, likely because of cold or wet spring weather, Badje noted. “But we shouldn’t stop trying to protect as many as we can.”
And even if the eggs hatch, many turtles never make it past their first birthday.
“It’s a tough life out there for a young turtle,’’ Badje noted. But wood turtles can live for 50 or more years. If they aren’t eaten or run over. “Protecting adult females, and turtle nests in the wild, are the best ways to conserve turtle populations in Wisconsin.”
It’s June: Time to give turtles a hand
Most turtle species in Minnesota and Wisconsin make seasonal movements, and many of them are on the move the most in June, seeking out places to lay their eggs and then spend their summer.
In some cases female turtles seek out the loose sand and gravel that’s along roadways to build their nest in June, making them even more vulnerable to being hit by vehicles. Highway mortality is considered a major reason several species of turtles are seeing declining populations.
Helping turtles safely across roads, particularly females with eggs, is vital to the preservation of regional populations. So both the Wisconsin and Minnesota departments of natural resources are asking people to give turtles a break on the road and, if possible, give them a helping hand across the road.
Here’s how you can help:
- Slow down. Drive with caution in June on all roads near creeks, rivers, ponds and lakes.
- Move the turtle off the road. Don't put yourself or others in danger: Simply pulling off the road and turning on your hazard lights may alert other drivers to slow down. Be aware of your surroundings and traffic before rushing to help.
- Avoid excessive handling and maintain direction of travel: Always move turtles in the same direction they were traveling in when encountered. Turtles should always be moved across roadways in as direct a line as possible. Don’t, for instance, take them to the nearest lake. That may not be where they were going.
- Allow them to cross on their own if possible: When turtles can safely cross roads unaided due to a lack of oncoming traffic allow them to do so. Observe from a distance and avoid rapid movements that may cause turtles to change direction, stop or seek shelter within their shells.
- Handle gently, beware of pee: If necessary to pick them up, all turtles except snappers and softshells should be grasped gently along the shell edge near the midpoint of the body. Many turtles empty their bladder when lifted off the ground, so be careful not to drop them if they should suddenly expel water.
- Don't handle snappers or softshell turtles: These two species can and will bite you and can be very aggressive. Either gently prod them off the road (again, in the direction they were headed) with a stick or keep watch nearby until they have safely crossed.
- Document your turtle find: Send a photo along with your location information. In northern Minnesota you can report your sightings to the regional nongame wildlife program staff. In Northeastern Minnesota, send the information to firstname.lastname@example.org . In Northwestern Minnesota, email email@example.com . Elsewhere in Minnesota, report turtle crossings and turtles deaths at herpmapper.org/register . In Wisconsin, go to dnr.wisconsin.gov/topic/WildlifeHabitat/HelpHerps .
- If you know turtles are nesting on your property, consider installing a nest protection device. It can be as simple as an old milk crate turned upside down to keep predators from digging up the turtle eggs. The Wisconsin DNR offers plans for a home-built turtle nest protector. Follow these instructions and watch a step-by-step video on how to build a nest cage that keeps predators out and allows hatchlings to exit on their own.
- Report turtle poaching. There is still an active, illegal trade in protected turtles sold for pets. If you see suspicious activity contact a warden by calling the Minnesota Turn in Poachers Line at 800-652-9093 or Wisconsin Turn in Poachers Line at 800-847-9367.
For more information on turtles in Minnesota, go to dnr.state.mn.us/reptiles_amphibians/helping-turtles-roads.html . In Wisconsin, go to dnr.wisconsin.gov/topic/WildlifeHabitat/HelpHerps.