Predator drones guard nearly half the US-Mexico border where camera towers, ground sensors, agents, and fences are absent. Able to patrol remote areas like mountains and canyons, the drones capture high-resolution footage of an area every three days, the AP reports in an exclusive. Analysts then check the videos using software, which shows everything from animal tracks to the footsteps of those who may have entered the US illegally, sources say. If something seems amiss—which has been the case in about 800 of 10,000 total missions—agents or helicopters search the area for human activity. Overall, the drones have found evidence of some 200 illegal crossings since March 2013. All those missions that come up empty are what the Border Patrol chief calls "proving the negative"—reinforcing that there's no need for agents.
As Border Patrol has "finite resources," the drones help move "resources to where you have a greater risk, a greater threat," says a Customs and Border Protection commissioner. Agents monitor weather, maps, and real-time images taken from the drones using about a dozen computer monitors. When an illegal crossing is suspected, ground sensors are usually planted nearby. The drones fly out of Corpus Christi, Texas, or Sierra Vista, Ariz., and patrol some 900 miles of border, mostly in Texas. However, officials hope to transfer the same technology to the Canadian border next year. Worried your law-abiding self might be caught on camera? A rep notes license plates and faces are unrecognizable. (Read more Border Patrol stories.)