The brown tree snake, a tree-dwelling reptile native to Australia, Papua New Guinea, and several Pacific islands, was inadvertently brought to Guam after World War II, likely by cargo ships.The snakes spread rapidly, obliterating populations of local wildlife and driving 10 native bird species extinct. They have since inspired many attempts to control the invaders, from air-dropping drug-filled mice to snake-detecting dogs, but none have been successful.

In 2016, Colorado State University ecologists Julie Savidge and Tom Seibert had another idea: Installing eight-inch-wide metal cylinders—a type of baffle used to deter wildlife—at the base of bird nest boxes at the U.S. Geological Survey’s brown tree snake laboratory.

They suspected the nocturnal snakes couldn’t