The flight was one of a number of sorties connected with a feral animal control program. Each sortie was approximately two hours duration. When approximately 32 kilometres north of Turkey Creek whilst returning from a sortie, the aircraft suffered an engine failure due to fuel exhaustion. An auto-rotation from approximately 150 feet above ground level was initiated. The most suitable landing site was an area of light timber surrounded by some larger trees with numerous ant hills nearby. At a height of approximately 15 feet above the ground, the pilot introduced pitch control to place the aircraft into a high flare in order to avoid a run-on landing into the trees and ant hills. The aircraft subsequently made a heavy touchdown.