Researchers continue study of unique population of Blanding’s turtles in McGregor Bay

Reta Meng holds one of her Blanding’s turtle research subjects, with radio tag and antenna visible on turtle shell.

MCGREGOR BAY—Travelling by small aluminum fishing boat, the site is approximately 30 minutes from J&G Marina in Birch Island. The unique habitat for this population of endangered Blanding’s turtles is what attracted researchers to study them.

At the helm is researcher/masters student Reta Meng, accompanied by Ph.D. student Kelton Adderley-Heron. They’ve already spent time in McGregor Bay tracking these turtles. Ms. Meng tagged six females last year. In early May, they radio tagged an additional eight turtles, bringing the total number of tags to 14. They returned in late May and throughout much of June to track and collect data from the tags. June is an important month as it’s nesting season. Females have GPS units attached as well as radio backpacks, to gather additional data about nesting habits and habitats.

The first stop was a coastal wetland on a small island. Locations cannot be disclosed for species at risk. Blanding’s turtles are threatened in Ontario. In Canada, the Great Lakes/St. Lawrence population has been listed as threatened since 2005 but in 2016 was re-assessed as endangered by COSEWIC (Committee on the Status of Endangered Wildlife in Canada).

How the first Blanding’s turtle made it to this island, well away from the mainland, may remain a mystery. This is their mainland now. The well-established population was discovered by local cottagers. In 2019, Dr. Patricia Chow-Fraser, a professor in the biology department at McMaster University, was staying with host family John and Gillian Woodroofe when the subject of Blanding’s turtles arose. Dr. Chow-Fraser realized there was a never-before documented population of the threatened turtle in the area based on their stories and photos.

Dr. Chow-Fraser and Ms. Meng then applied for and received funds from the Habitat Stewardship Protection Fund to carry out a scientific study over a two-year period. This is year two of the project.

At the island, the researchers don chest waders and prepare the antenna and receiver. Ms. Meng stands on the highest rock and listens for the frequencies of all the turtles. Each radio tag has its own frequency, and louder means closer. “We usually start with the closest turtle,” she said. “Once that one has been found and the information recorded, we listen to find the next closest one.”

When compared to other studies, this population of Blanding’s turtles seem to use more open water, Ms. Meng explained. “The wetlands here are more coastal. They’re islands, and there’s not as many inland big wetland complexes that are good for Blanding’s.”

What she’s found is that the turtles actually swim across the open water to different islands, where they sun along the rocky shorelines. “It’s not commonly talked about in previous literature,” she said. “I’m trying to compare this population to other studies of populations across their range. The home range of these Blanding’s seems to be smaller as well.”

That’s not confirmed, she cautions. There’s only one year of data so far. “I wouldn’t be surprised,” she said. “There’s nowhere they can really go to.”

It could indicate there’s a really good food source and good habitat here, added Mr. Adderley-Heron. “Sometimes the food source is vegetation. Sometimes it’s dead animals. As they get older, their diet shifts towards small fish, minnows. They do eat some vegetation still.”

They’re good at cleaning up the wetlands, he said.

This first wetland they’ve stopped at is shielded from the wind. There’s another wetland on the other side of the island that’s more open. “It can get windy, and the water level will rise if the wind blows into this,” Ms. Meng said. The water level in this wetland is mostly steady though. The cattails shield the area from much of the wave action.

They walk through the cattails, following the beep. In places, the water reaches to their waist. Earlier in the season and last year, the water level was much higher. They couldn’t walk through then. On this day, the wind is calm and it’s warm but not hot. There are some boats on the water but none passing near. The marsh is loud with the sound of birds. It takes several hours to find all of the turtles. The researchers head out daily, tracking half the turtles one day, half the next. It can be tedious, slogging through wetlands thick with cattails, then clambering over dead trees and moss-covered rock islands in all weather.

Sometimes the turtles are found underwater. They spend a lot of time underwater, especially in shallow environments where the water is warm. Sometimes the turtles bury themselves under the mud.

“One of my turtles has only one eye and I think she feels safer in here,” said Ms. Meng. “Last year she spent basically the whole summer in this pool area. It’s very protected.”

Ms. Meng has named each of the turtles. The one-eyed lady is called Gertie. “They each have their own personalities,” she said.

For the researchers, these skills are transferrable. Radio telemetry is used on everything from rabbits to small game, and GPS technology is used on larger animals like wolves. Ms. Meng hopes to continue this project for another four years while she completes her Ph.D. and is hoping to work even more with Whitefish River First Nation. “They’ve already been coming out,” she noted. “They’re very interested.”

When the project is complete, Ms. Meng hopes they will carry on monitoring and stewarding these turtles. She also hopes to continue working with the McGregor Bay Association cottagers. She likes the outreach. “It’s more like a partnership than working with volunteers. They’re happy we’re doing this because it will help them. They are all concerned about the environment. They all know their neighbours. They’re all connected so you get a network of information, which is really helpful.”

Ultimately, understanding the habits and habitat of this population of Blanding’s turtles will enable local communities to monitor their health and safety, especially in a changing climate.

“This is almost at their northern range limit and if the temperatures continue to change, their limit would likely move northward,” Ms. Meng said. “We’ve already seen with changes in water level, the habitat changes a lot. When I first got here three years ago, the water level was extremely high. We actually did go back to that specific wetland and the landscape was completely different. Because it was also super dry, the turtles were pushed back further into the wetland.”

That was just a seasonal fluctuation, she acknowledged. “They are very adaptable animals but if it’s very fast, in terms of water level fluctuation, that would affect how much habitat they have. And once the trees and bushes get inundated, it takes a long time for the wetland to return to its original state. Vegetation would start rotting and nutrient levels could change as well. That can set off a chain reaction.”

Turtles are very temperature dependent, added Mr. Adderley-Heron. Even at its most basic, eggs are temperature sex dependent. If a turtle’s eggs incubate below 27°C, the hatchlings will be male. Hatchlings will be female if eggs incubate above 31°C. In a warming world, there may be issues in the long term with a skewed sex ration.

“At its most basic, turtles need the habit and habitat changes could affect them,” he said.