PRANBURI, Thailand — They are 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 is still the ‘‘dawn of drone ecology,’’ as one innovator calls it, these unmanned aerial vehicles are skimming over Indonesia’s jungle canopy to photograph orangutans, protect rhinos in Nepal, and study invasive aquatic plants in Florida.