Police are also investigating threatening phone calls the man says he received.
Jeff Damen was doing preliminary work at the site of a proposed wind farm in the community of West Grey, near London last week when he says a red pickup truck pulled alongside his vehicle and the driver asked what he was doing.
After Damen explained the work he was doing, the driver pulled out a gun, Damen said.
"He reached over his back seat, and pulled out a shotgun, pointed it at me and stated, 'Why don't you leave us all alone? If I catch you back here again, I'm going to kill you,'" Damen said.
Damen was unable to get a licence plate number. It was covered by a folded down tailgate.
West Grey Police Const. Janet Shumaker said Damen was alone at the time of the alleged incident but the police are taking the matter seriously.
"This is the first time something like this has ever happened," Shumaker said.
Damen said he then received some cryptic phone calls Monday.
"They stated they know where I live and know what I do," he said. "That's pretty much how they left it and hung up."
The father of two, who lives in a rural area, said he has had some sleepless nights.
Bill Palmer opposes wind farms and claims the province refuses to listen to health and safety concerns. So he's not surprised tempers are flaring over wind farms.
"That's unfortunate. I mean I hate to see that happen, but it's what happens when you divide society," Palmer said.
Damen said it's not the first time he's been confronted in his field of work.
"I have encountered verbal attacks, personally to me, regarding wind, but it has never escalated to this point," he said. "This has gone to a new level of my safety, for sure."
Shumaker said police continue to investigate.