Concentrated mostly along a 220-mile western stretch of border that includes an Indian reservation, a wildlife refuges and a military range, the drones are only the latest hardware in the patrol's technological toolbox - which includes tower-mounted cameras, ground sensors, night-vision goggles and portable lifts that let agents view down lines of highway traffic. The hope is the drones can help stem a surge in illegal immigration that a buildup of border agents hasn't stopped. The remotely piloted Hermes 450 craft, which can stay aloft for 20 hours at a time will carry cameras with thermal and night vision capabilities...