On a chilly morning in Denver’s City Park, some 600 Canada geese floated like a drab armada atop an icy pond.
A truck pulled up, and a collective murmur rose from the gaggle, suspicious but not alarmed. Scott Bartell, a technician with the parks department, hoisted out a 3-foot-long, orange contraption festooned with wild eyes and a snarling face.
He plunked it into the pond and switched on the remote control. A shrill whine went up as he slowly steered the gadget toward the geese. The birds panicked, lifting off in a cacophonous rage. In seconds, the pond was clear.
Chalk up another win for the “goosinator,” a critical tool in Denver’s...