The Canadian army’s unmanned spy drone, the Sperwer, may sound like a domestic lawnmower but the noise is enough to pin down the Taliban in Afghanistan. “At night when things are quiet, this is a two-stroke motor so you know it’s in the area,” says Major John Casey, head of an operation using the French-made drones at the coalition air base in the southern city of Kandahar. The effect of the sound on Taliban insurgents was demonstrated during a sweep last month by Afghan security forces in the west of Kandahar province. Full Story