PRANBURI, Thailand -- They're better known as stealthy killing machines to take out suspected terrorists with pinpoint accuracy. But drones are also being put to more benign use in skies across several continents to track endangered wildlife, spot poachers and chart forest loss.Although it's still the "dawn of drone ecology," as one innovator calls it, these unmanned aerial vehicles are already skimming over Indonesia's jungle canopy to photograph orangutans, protecting rhinos in Nepal and studying invasive aquatic plants in Florida.Read More... More on Drones