electric scarecrow
n.— «Residents in the area near the Country Ribbon plant complained to city hall about the loud sound system that the plant was using to keep crows and seagulls away from its caged chickens. The plant, in the Pleasantville neighbourhood in the city’s east end, uses what’s called an electric scarecrow, which plays recordings of random loud noises.» —“Chicken plant told to cut crow-scaring racket” CBC (Canada) Aug. 16, 2006. (source: Double-Tongued Dictionary)