Turtle Tunnel Provides a Rare Glimpse Into the Secret Lives of Wildlife

When Washington County and Washington Conservation District installed a small tunnel beneath Hwy 4, just south of Big Marine Park Reserve, they hoped that the project would provide a safer crossing for turtles in the area and help to protect the rare Blanding’s turtle. Part of a larger research and habitat restoration project, funded by the Minnesota Department of Natural Resources, Minnesota Herpetological Society, and Carnelian-Marine-St. Croix Watershed District, the tunnel is located along a stretch of road between the park and a large wetland complex where female turtles lay eggs in the spring. Now, three years later, project partners have thousands of photos taken by a motion-activated camera that document the secret lives of turtles and other wildlife using the crossing.

One frame captures a wide curve of shell, hind leg, and a pointed tail disappearing into the shadows. In the next image, you can see the animal’s full body. It is a large snapping turtle, staring straight into the camera. Next comes an opossum, sniffing along with its nose to the ground. There is a baby snapper, no bigger than a silver dollar, followed by a painted turtle, slightly blurred by the speed at which it was moving. There are photos of garter snakes, leopard frogs with and without spots, brown weasels that turn white in the winter, an army of mice and voles, and a mother duck leading a trail of ducklings. Finally, at long last, the camera captures a Blanding’s turtle passing through.

A motion activated camera catches the backside of a snapping turtle as it passes through the turtle tunnel on Washington County Hwy 4.
A second photo, showing the snapping turtle from the front.
Garter snake
Weasel in summer.

Blanding’s turtles are a threatened species in Minnesota that has lost vital upland and wetland habitat due to development and farming. In addition, many females are killed by cars while traveling to lay eggs in the spring. Blanding’s rely on a mixture of intact wetlands, lakes, grasslands and sandy, rocky open areas for breeding and nesting and will travel up to a mile from the water’s edge to lay their eggs. They prefer calm, shallow water bodies with muddy bottoms and lots of lilies and aquatic plants; large marshes bordering the Mississippi and St. Croix Rivers are ideal. They also frequent small temporary wetlands that dry up in the late summer or fall.  Northern Washington County, including Big Marine Park Reserve, contains this special mix of habitat types and, therefore, is one of the few places in the state where Blanding’s turtles still roam.

This fall, the Washington Conservation District finally captured a photo of a Blanding’s turtle in the tunnel. Blanding’s are a threatened species in Minnesota.

The grainy images from the Washington County turtle tunnel provide a rare glimpse into the secret lives of the Blanding’s and other wildlife that share our woods and wetlands. Some of the animals are only active at night when the rest of us are sleeping. Others have become adept at camouflaging their bodies, lying silent when human footsteps approach.

In addition to protecting wildlife, the turtle tunnel has made Hwy 4 safer for human drivers as well. People used to swerve to avoid hitting turtles in the road, or pull onto the shoulder and run out into the highway to move them. Now, a curved barrier helps to keep turtles from climbing up onto the road and directs them into the tunnel.

The turtle tunnel, shortly after installation. It is made of concrete, inlaid into the road, with openings on the top to let in light. 

If you would like to help protect turtles in your community, here are a few tips:

  1. If you live on a lake, river or wetland, leave fallen logs in place to create basking locations for turtles. You can also work with the Conservation District and local watershed district to improve shoreline habitat with native plants.
  2. If you see a turtle crossing the road, carefully help it across in the same direction it is traveling, but only if it is safe to do so. Beware that snapping turtles can reach their heads two-thirds of the way back their bodies; use gloves if you have them, hold onto their shells as far back as possible, and never grab them by the tails.
  3. Download an app to your phone to help track locations where turtles are frequently crossing roads in the metro area. Data collected will be used to generate maps to prioritize additional wildlife tunnels and crossings. Learn more at mnherps.com.