“Someone is coming up behind you,” species-at-risk biologist Scott Gillingwater says. We lower our voices and change the subject. The two of us look conspicuous; we’re wearing chest waders and sun hats and are standing on the edge of a potholed road beside a grassy path near a marshy wetland. I turn to see a man with binoculars and a large camera approaching. He is either a birder or a turtle poacher posing as a birder. “Anything good?” Gillingwater asks him, gesturing skyward. “No, not yet,” he replies.

We wait for the man to disappear down the road and step onto the path to begin our clandestine operation. Gillingwater, who works for the Upper Thames River Conservation Authority in southwestern Ontario, has agreed to show me the top-secret area where he studies spotted turtles. It is one of Canada’s last natural strongholds for the endangered reptile, he says, home to “an exceptionally important population.”