MACDOEL (California), Aug. 6 -- Wolves are killing cattle across the American West - so US wildlife officials are turning to an unusual new defence: drones blasting AC/DC and audio from Marriage Story.

The US Department of Agriculture (USDA) is using quadcopters equipped with thermal cameras and loudspeakers to patrol ranches and drive away wolves without physical force, The Wall Street Journal (WSJ) reported earlier this month.

This is because wolves remain protected under US federal law.

Among the deterrents played over drone speakers are fireworks, gunshots, and recordings of people arguing, including the intense shouting match between Scarlett Johansson and Adam Driver in Marriage Story.

"I need the wolves to respond and know that...