Weather impacts a turtle's sex and other facts to note during turtle nesting season

It's turtle nesting season in Ontario and conservationists are working to protect endangered species and their nests. 

"Right now, we're at the peak of nesting season," said Scott Gillingwater, a species at risk biologist with the Upper Thames River Conservation Authority (UTCRA) based in London, Ont.

"Most turtles are laying their eggs in June, though the season can stretch from late May to mid-July. With the cooler weather this year, the timing seems typical."

Gillingwater and his team have been out in the field, searching for nests and relocating eggs from vulnerable sites, particularly those of the endangered spiny softshell turtle.

"These turtles face serious threats from habitat loss, flooding, predators like raccoons and skunks, and even poaching," said Gillingwater, speaking from the banks of the Thames. "We incubate the eggs and return the hatchlings to the wild. It's been a key part of helping the population rebound."

That effort has spanned three decades, and Gillingwater said it's working.

"We had an aging population when we started in the 1990s. Now, we're seeing turtles of all ages, including young females nesting for the first time. For a species that takes 15 to 20 years to reach maturity, that's a major success," he said.

Spiny softshell turtles aren't the only ones under threat. The team also monitors and protects nests of snapping turtles, map turtles, Blanding's turtles and others across the region. Gillingwater estimates they currently have nearly 500 nests in incubators, representing as many as 10,000 hatchlings.

This year's nesting season has been one of the busiest for Kelly Wallace of the Think Turtle Conservation Initiative, which provides education and species recovery efforts across Ontario. 

Temperature fluctuations throughout the spring delayed and shortened the optimal nesting window, resulting in numerous turtle nests all out at once, she said, adding that climate change is having a "dramatic effect" on the turtle population. 

"Their movements are so in-tune with environmental changes, they're sort of an indicator species to give you an idea of what's going on in the ecosystems," said Wallace. 

"The sex of the eggs is temperature dependent, and because we're having such hot temperatures, there's more of a leaning toward female hatchlings. That's concerning because down the line we may end up with more females than males." 

Many turtles are also not reaching maturity age, leaving a gap among the breeding population and the amount of hatchlings to repopulate, largely due to road mortalities and habitat loss, she said.

If you spot a turtle crossing a path or road, Gillingwater said, you can help, but only if it's safe.