After the first Japanese air raid on Darwin in February 1942, Australian aircraftman Percy Westcott heard whimpering under the ruins of a mess hut and discovered a stray six-month-old Kelpie with a broken leg.

Westcott had the leg set and the two became friends. About a week later, “Gunner” revealed a special talent. As the RAAF personnel went about their normal routines at the airfield, the dog began to show signs of agitation, whining and jumping, and a few minutes later a group of Japanese aircraft appeared over Darwin, bombing and strafing the city. This happened again two days later, and successively throughout the weeks that followed.

It turned out that Gunner could hear approaching Japanese aircraft up to 20 minutes before they arrived, long before warning sirens sounded and before the planes had been detected by radar. He could even distinguish Japanese from Allied engines. He proved so reliable that the squadron’s commanding officer allowed Westcott to sound a portable air raid siren when Gunner alerted him to approaching attackers.

The dog became an inseparable member of the squadron, sleeping under Westcott’s bunk, showering with the men, sitting with them on outdoor movie nights, and even flying with them as they practiced takeoffs and landings. When Westcott was posted to Melbourne 18 months later, he left Gunner with a local merchant. What ultimately became of him is unknown.