LIWONDE, Malawi — Night has fallen at Liwonde National Park, but the trespassers are clearly visible. Three hundred feet in the air, a thermal camera attached to a BatHawk drone tracks their boat, a black sliver gliding up the luminous gray Shire River.

“They’re breaking the law by coming into the park,” said Antoinette Dudley, one of the drone’s operators, pointing to her computer screen.

More than two miles from the boat, she and her partner, Stephan De Necker, are seated in a Land Cruiser that serves as their command center. A monitor attached to the driver’s seat displays the drone’s vitals, and another behind the passenger’s seat streams live video from the camera, operated with an old PlayStation console.

“Let’s give them a scare,” said Mr. De Necker. With the tap of a few keys, he switches on the drone’s navigation lights and sends it beelining toward the boat.