“It’s OK,” Bonnie Siegfried said softy, trying to comfort a convulsing pigeon wrapped in a fleece blanket. The bird’s body was twitching violently, its beak chattering as she held it in her arms. The pigeon died after about a half an hour as Siegfried, who lives in London, in the Canadian province of Ontario, waited for an animal control officer to arrive. She later posted a video of the pigeon to Facebook.

In the weeks after that incident in late August 2020, several London, Ontario residents and neighbors reported seeing numerous pigeons in distress—falling out of trees, flapping their wings, convulsing, gasping in distress, and dying. A necropsy later concluded the pigeons had been poisoned with Avitrol, a