They see many things meant to be secret, like men having sex with sheep and goats in the deep of night. I first heard this from infantry soldiers and took it as rumor, but at Bagram I met a civilian contractor who works in UAV operations. “All the time,” he said. “They just don’t think we can see them.” Which sums up a major allure of UAVs: Though they should know better by now, many insurgents still feel safe working in darkness or in the shelter of distant mountains and valleys, so they are exposed again and again. The unmanned planes have eroded their freedom of movement and simple early-warning systems, two of their few assets when outmatched in weapons, technology, and resources. Helicopters can be heard a mile or more away. Spotters watch vehicles leave bases and follow the slow advance of dismounted patrols. Surprise is a rarity for U. S. forces in Iraq and Afghanistan. The insurgents almost always know they’re coming, with at least several minutes’ notice. So they toss weapons behind a rock and become, in an instant, civilians. But with a camera parked three miles overhead, last-minute subterfuge doesn’t work.