PROBLEM TO BE SOLVED: To reliably repel harmful animals from a farmland area without making the harmful animals get used.SOLUTION: A system includes: multiple detection units 2 arranged at predetermined intervals at the outside of a farmland area 1 and for detecting a harmful animal 4 invading the farmland area 1; a small unmanned aircraft 3 capable of flying three-dimensionally; an intimidating unit provided in the unmanned aircraft 3 and for intimidating the harmful animal 4; and a recognition unit provided in the unmanned aircraft 3 and for recognizing the harmful animal 4. The unmanned aircraft 3 (i) starts a flight on the basis of detection of the detection unit 2, and (ii) intimidates the harmful animal by the intimidating unit and repels the harmful animal from the farmland area 1 on the basis of recognition of the recognition unit while approaching and tracking the harmful animal 4.SELECTED DRAWING: Figure 2
