Supporting MCV has never been easier!


Contribute Now

Subscribe

Give a Gift Subscription

Update My Subscription

About MCV


Past Issues

School Resources

Contact Us

Annual report

FAQ


Connect with us!


image of Facebook icon image of Twitter icon image of Google plus icon

Image of a turtle.

A Midsummer Night's Nesting

By the light of a June full moon, Blanding's turtles trek out of the
marshes and onto the uplands to dig their nests and lay their eggs.

by Gustave Axelson

"This is a Blanding's turtle," said Lisa Gelvin–Innvaer, a regional nongame wildlife specialist with the Department of Natural Resources, as she reached into a mesh bag and pulled out a very large turtle.

It was about the size of a football, 12 inches long and sharp-looking, with a bright yellow chin and throat. The bottom shell, or plastron, is decorated with a distinct black and yellow inkblot pattern.

Tracking Turtles
warbler image

See more images of biologists trapping, tagging, and tracking Blanding's turtles.

The turtle's head was buried inside. I bent down to meet it. It blinked its bulging eyes at me. Then, to my surprise, it extended its unusually long telescopic neck by 4 inches to close the gap between us. Clearly, this was no ordinary turtle, more like meeting E.T.

Indeed, the Blanding's turtle (Emydoidea blandingii) is extraordinary, with the wood turtle one of two threatened species in Minnesota. And this turtle was especially unusual because Gelvin–Innvaer trapped it here in a cattail marsh in Perch Creek Wildlife Management Area, about an hour's drive southwest of Mankato in the great corn sea of south–central Minnesota. That's about 150 miles west of Weaver Dunes along the Mississippi River, which is home to the largest concentration of Blanding's turtles in the state. The existence of other Blanding's turtle populations is key to the survival of the species in Minnesota, because any single population is always at risk of being wiped out by catastrophe or disease.

But a Perch Creek population of Blanding's turtles is viable only if it's reproducing, and that's what Gelvin–Innvaer and her team are trying to figure out. This turtle was a gravid female (with eggs). The previous night she had been captured in a live trap baited with sardines. Then a researcher had epoxied a tiny radio transmitter to her shell, and she spent that night in a plastic tote while the glue dried. Now Gelvin–Innvaer prepared to release the turtle exactly where trapped—an hour's slog, deep into a marsh of 6-foot-tall cattails.

Angry red-winged blackbirds mobbed the air above. The funky smell of decaying plant matter emanated from the knee-high muck. Gelvin–Innvaer gave the turtle a final examination before letting her go. "She's about ready to nest," she said, feeling the bulges of eggs above her rear legs. "Maybe she'll do it tonight."

I was with Gelvin–Innvaer, DNR nongame wildlife specialist Laurinda Brown, and DNR photographer Deb Rose to witness Blanding's turtle nesting. We were there on that particular night because it was a full moon. During the past two years, several of the turtles Gelvin–Innvaer has tracked via radio transmitters have nested during the week of a full moon in May or June. She thought this night—the June Strawberry Moon, according to Farmers' Almanac—the radio transmitter–tracked female turtles might crawl out of the marshes and onto the uplands to nest. They would practice a ritual as old as the prairie—even if the prairie isn't there anymore.

Talking With Farmers

A farmer first found Blanding's turtles living in this area. He clued in Soil and Water Conservation District technician Rich Perrine, who came upon more turtles while at Perch Creek WMA on another assignment. In 2003 Perrine sent photographs to the DNR.

With the help of T.J. Jessen, a contracted surveyor, Gelvin–Innvaer began surveying Blanding's turtles in the area in 2009. Since then, she and her team have captured 59 turtles, weighed and measured each one, and estimated age by the treelike growth rings on the shell's plastron. They have outfitted 34 turtles with transmitters.

Historically, Blanding's turtles were widespread across the eastern and central United States, with the core of the range in the Great Lakes region. Minnesota is at the northwestern extent of the species' range. In 1984 the DNR listed the Blanding's turtle as a threatened species in Minnesota. It is also endangered in Illinois, Indiana, Maine, Nebraska, Massachusetts, South Dakota, and Missouri.

A map of a Blanding's turtle's territory shows a mosaic of wetlands and upland grassland. They are prairie turtles, all-terrain amphibious reptiles that can rumble more than a mile overland to nesting sites. In spring and early summer, they hunt tadpoles and other small aquatic prey in the shallows of wetlands, streams, ditches, beaver pools, and rivers. They move to deeper waters to stay cool in later summer. They overwinter in ponds, wetlands, and, most frequently in southern Minnesota, streams.

Like ducks, Blanding's turtles need one of Minnesota's scarcest habitats—large prairie-wetland complexes. As more prairie remnants were plowed up and planted to crops in the 20th century, nesting habitat diminished and Blanding's turtle populations dwindled. They can live more than 80 years, but they don't reach sexual maturity until at least age 12, so they can't quickly repopulate after being decimated.

One of Gelvin–Innvaer's first actions upon launching her Blanding's turtle research project was outreach to farmers, who might own land with turtle habitat. She began by stopping by farms to talk about Blanding's turtles, habitat conservation in Martin County, and her project. Conversations took place in farmyards, in kitchens, and along roadsides.

"We talked about how Blanding's turtles not only use wetlands and streams, but also are upland nesters. Today, most of those former upland prairies are crop fields," she said. "We realize that this is a working landscape. It's not 'us versus them.' Rather, it's how can we collectively do something for the land and the people. For example, upland buffers can provide critical nesting habitat for turtles and other wildlife. Other benefits include cleaner water and reduced flooding and erosion."

Blanding's turtle conservation is part of an overall strategy for healthy watersheds.

"Reaching out to landowners is really important. Initially, it's vital for the project to get permission to survey and track turtles," said Gelvin–Innvaer. "Quite a few have become really interested and help with reporting turtle sightings. They've developed a sense of ownership in the project. We're so grateful for all of their support."

Muddy Back Roads

Gelvin–Innvaer pulled her DNR pickup truck as far down the muddy back road as she could go without getting stuck. Then she, Brown, Rose, and I hopped out and walked downhill to Perch Creek marsh. The wet areas were WMA land. Ankle-high corn grew in fields of black earth on either side.

It was dusk. Red-winged blackbirds got in their last chortles before dark. Chorus frogs called like creaky doors. Brown waved an antenna to listen for turtle-transmitter beeps.

"A few days ago, there were several turtles deep in the marsh," Brown said, "but now I'm picking up four females that have moved to the edge of the marsh. They're getting ready to move into the crop fields."

Back in the 1800s, Blanding's turtles would have sought out dry hill prairie along the creek for nesting. Dry prairie had shorter grasses than tallgrass prairie and allowed sunshine to penetrate and warm the eggs for incubation. To Blanding's turtles today, a cornfield in June looks like a pretty good nesting place, with soil readily dug for a nest and warmed by the sun. Unfortunately, by late summer, corn plants will shade the ground. And when farm machinery rumbles through the fields, eggs could get crushed.

A harsh reality about Blanding's turtles in farm country: Every one of the female Blanding's turtles that were radio-tracked by the Nongame Wildlife Program in this study area has nested on private land. The researchers have yet to find evidence that hatchlings are making it to wetlands. The project surveys have found mostly older turtles—between 20 and 30 years old. "It's like a town on the decline that's mostly made up of senior citizens," she says. The population seems to be skewed toward older turtles, with no younger generations to replace them after they die. Gelvin–Innvaer adds that her team's research is inconclusive on that trend. "We're still working to discover whether the apparent lack of younger turtles is related to habitat, or perhaps our survey methods are more likely to capture adult turtles," she says. "Or perhaps a bit of both."

Gelvin–Innvaer said that part of the problem could be lack of detection, since Blanding's turtle hatchlings are really hard to find. "They're like looking for moving dirt clods," she said of the quarter-sized baby turtles. Nevertheless, she said, a shortage of suitable upland nesting habitat is undeniably hurting Blanding's turtle reproduction. Her hope: The data on nesting locations might help lead to conservation easements that create nesting areas for Blanding's turtles. She called it a lofty hope, considering agrarian land economics. "Cropland in this county goes for as much as $9,000 an acre," she said. "And there isn't much money for protecting Blanding's turtles."

Yet, Gelvin–Innvaer is pinning her hopes on what she knows about farmers. "Not every special place is grand like the Rocky Mountains. This is a special place too, a place worth saving," she said. "And people are part of this place. … Farmers have an ethic of taking care of the land for future generations. So it's just a matter of talking to these farmers and working with them to create a landscape that's good for people and for turtles and for the health of the land."

Full Moon

None of the four turtles made a nesting run that first night of our vigil. The next night I sat in a muddy cornfield with Gelvin–Innvaer, Brown, and Rose. We were about 10 feet away from a Blanding's female turtle that had trekked out of the marsh and a few hundred feet into the field. She stopped there and dug for about an hour.

It was dark, about midnight. Chorus frog calls were replaced by the shrill trilling of toads and buzzing of mosquitoes. Farm lights shone above barnyards in the distance; pickups with throaty exhaust rumbled down country roads. The bright glowing eye of the full moon cast an ethereal white sheen on the corn plants and the annual migration of Blanding's turtles from water to land to lay their eggs.

"OK, come quick, take a peek!" Gelvin–Innvaer whispered. I ran over to her, shining my headlamp a few feet to the left so as not to disturb the turtle with direct light. Between two corn stalks, the turtle had backed into her freshly dug 6-inch furrow. She shuffled her rear legs, and then a white, glistening orb appeared beneath her shell and dropped into the nest. It was beautiful.

Gelvin–Innvaer was clearly moved as we backed away to give privacy to the turtle as she labored to lay perhaps another five to 15 eggs in her clutch. She spoke quietly but with conviction: "This is why we don't give up. You just don't give up on a place like this."

The following October, a joyous email rang into the inbox on my computer. "We found one!" Gelvin–Innvaer wrote. A baby Blanding's turtle hatchling, about the size of a quarter, spotted near Perch Creek—an optimistic sign for the future.

Learn more about Blanding's turtles with the DNR Rare Species Guide. To report sightings in southwestern Minnesota, email lisa.gelvin-innvaer@state.mn.us.

Looking for volunteer opportunities?