Tracking endangered orangutans was no easy feat a scant three years ago. It required counting treetop nests in places like the Leuser Ecosystem on Indonesia's Sumatra Island to gauge the health of a population that was under fire from poachers and palm oil barrens. Aerial surveillance using remote sensing satellites was often too expensive for local conservation groups and, even when affordable, the views were routinely obscured by cloud cover.

"I was thinking it would be a lot easier if we had a camera somewhere up in the sky that would take pictures of the canopy of the forest and allow us to determine where orangutans are and how many there are," says Serge Wich, a primate biologist at Liverpool John Moores University and an expert on orangutans.

A year later he and his colleague, Lian Pin Koh, chair of the Applied Ecology and Conservation Group at the University of Adelaide in Australia, launched their first unmanned aerial vehicle (UAV)—aka drone. Weighing a few kilograms with a wingspan of about two meters, the battery-powered and remote-controlled drones look more like model airplanes as they fly above treetops snapping geotagged photos or video during preprogrammed flights that last about an hour and a half. The project drew so much interest—8,000 views on their first YouTube video—that they set up an organization,, that promotes scientific use for UAVs worldwide. "I think it will revolutionize part of how we do conservation and rainforest ecology work," Wich says. The group has provided upward of 40 drones globally to conservation groups studying everything from illegal fishing in Belize to destruction of elephant habitat in Indonesia to fires from bush meat hunters in the Congo.

Drones are proving especially popular in combating the illegal wildlife trade, a booming, $10-billion-a-year business that until now has been an unfair fight between well-armed criminal syndicates and poorly trained and equipped park rangers.

Kenya, Tanzania and South Africa all have talked this year about using drones in their fight to stem the dramatic rise in poaching of elephants for their ivory and rhinos for their horns, both of which are popular in China. Across Africa 30,000 elephants—about three an hour—were killed in 2012, according to the World Wildlife Fund (WWF). The numbers of poached rhinos in South Africa increased 5,000 percent to 668 from 2007 to 2012. Although the population of black and white rhinos as a whole has risen to close to 21,000 in South Africa in recent years, those numbers could begin declining if poaching trends continue. "Year on year since 2007 we have seen an exponential increase in poaching in rhinos in South Africa," says Crawford Allan, director of TRAFFIC North America, a regional office of the world's largest international wildlife trade monitoring program run jointly by WWF and the International Union for Conservation of Nature. "It used to be there would be 10 to 12 rhinos killed a year for the 14 years leading up to 2007 in South Africa. But in the current crisis, we have reached 1,004 rhinos poached last year."

One of the most advanced drone programs can be found in Nepal, an impoverished south Asian nation where poachers take advantage of the rugged, mountainous topography to kill rare elephants, tigers and rhinos. Teaming up with the WWF the country has for the past two years trained 40 people to use six drones provided by Conservation Drones and will start monitoring Chitwan and Bardia national parks as early as August. But even the test flights have spooked poachers and led to a decline in illegal activities, although there haven't been any arrests attributed to the UAVs, Diwakar Chapagain, coordinator of the wildlife trade monitoring program for WWF Nepal said in a phone interview from Nepal. "There is another layer of security that is there, which is drones," he says. "The message to the public is that anyone going into the park can be monitored. Their picture can be taken by the UAV and, later on, they can be arrested. That will be a deterrent."

But much like the program in Nepal, it is still too early in most countries to say whether UAVs will have a dramatic impact on poaching. Almost all drone programs are in the early stages of development—they have to be tested first and rangers trained before they can be deployed—and their use in several African and Asian countries has been hampered by technological challenges and security fears.

Take the experience of Conservation Drones. They have at times struggled to get clearance to fly their UAVs in Kenya and South Africa, and their test flights have had mishaps. They have to be careful not to fly nearcell phone towers, which have beenknown to disrupt drone signals and accidents are a constant hazard. Trials have been upended when a drone crashes or fails during a flight. "We have had our fair share of ups and downs when we started," Wich says. "We had a bad crash of a unit once where we probably did not fix the battery well and it just got into a stall and crashed. We managed to find it and fix it up again. We have had a unit crash into a tall tree when we tried to take off in an area where there was little space to take off. And we also had accidents during landing when a tree was hit…, again because landing space was limited."

One of the biggest challenges is finding a drone that is affordable to many poor governments but also carries enough technology to be an effective tool. So far, Wich and others acknowledge they aren't there yet. The cheaper models don't provide crystal clear images and often require rangers to review videos or photos after a drone has landed, which puts them hours behind any potential poachers. They also don't have the capacity to carry heavier payloads (most can only carry a maximum of 800 grams) that might include radar and other equipment that can see through forest canopies.

The New York City–based Wildlife Conservation Society says it is testing drones in grasslands, forest and marine reserves but is frustrated by their small payloads and, like most conservation groups, is unwilling to spend upward of $200,000 for "ex-military, petrol engine airframes with 15-hour flight times and 15-kilogram payloads."

"We are in a bit of a catch-22. Unsure of their value we don't want to spend scarce funds on buying drones," David S. Wilkie, a wildlife ecologist who is also the WCS director of Conservation Support, said via e-mail. Wilkie believes drones will one day play a part in saving endangered wildlife by extending traditional ground patrols, detecting poachers at a distance and helping catch them before they actually kill. "If we can deploy ex-military–style craft with long flight times, durable airframes and [radar-] capable payloads, we will see tangible evidence of drones’ utility for protecting the safety and lives of park and community guards, and increase poacher arrests and crime prevention," he says.

More advanced systems are being tested in parts of Africa by WWF which has received a $5-million grant from Google to deploy a range of high-tech solutions in the poaching fight in Asia and Africa. It's drones are armed with expensive, thermal-imaging cameras that can spot humans or animals at night as well as technology that can track animals that have been tagged, including rhinos that have had radio-frequency identification (RFID) chips implanted in their horns.

Using a system like this authorities, can catch poachers in the act by identifying images of humans or other activities that might signal their presence, such as a campfire. They also can be used to protect rangers from a potential ambush as well as better understand the increases and declines of an endangered population or conflicts with local residents around the boundaries of a national park. "You actually get a heat signature of poachers, heat signatures of vehicles or camp fires or whatever it might be," Allan says. "It's on the UAV in real time, feeding it back to a central control station or even rangers themselves on the ground. It tells them that behind that row of shrubs or trees you have five heat signatures glowing out, which could be a potential ambush so you have to be careful."

Allan says he expects the technological advances to come in the coming months and years but that security fears will take longer to assuage.

In the meantime these concerns have prompted some countries to slow deployment. Kenya and South Africa reportedly halted the private use of UAVs in June while India's defense ministry suspended the use of drones in tracking poachers of its endangered, one-horned rhino in one national park in the country's northeast.

Some countries are putting the kibosh on UAVs until regulations can be drawn in the next year or two on their commercial use whereas others, in more volatile regions of the world, may be hesitating over fears the drones could fall into the hands of terrorists or anger a neighboring country who might fear the aircraft are spying on border regions or taking stock of their military assets. There also are concerns from privacy groups that the drones may be used by authorities to spy on individuals.

Allan calls the privacy fears "ludicrous," considering most UAVs operate in remote wildlife reserves, although he acknowledges there remains a lot of "drone-phobia" around the world because they had been used until recently almost exclusively on the battlefield to kill alleged terrorists in places like Afghanistan, Yemen and Iraq. "Countries are very rapidly having to formulate their own plans, regulation and rules about the use of [unmanned] aerial vehicles in their countries," Allan says. "Some of them are saying, until we figure this out, nothing is happening. … As with any type of technology that is new and has broader implication that not everyone really understands fully yet, you have to figure out what are the rules and safeguards that you need to deploy to make sure it's done effectively so you don't get the cowboys coming in and doing the wrong thing and making a mess for everyone else."

Allan notes that a possible compromise might be for countries to pass laws allowing drones for use in private game reserves or in government-owned parks where there is controlled air space "as long as it's done safely and doesn't impinge on anyone's privacy."

Adam Watts, assistant research professor in fire ecology at the Desert Research Institute in Reno who has done extensive research on drones, says a balance will eventually be struck and the benefits of UAVs will overcome security fears. The more they prove their worth—whether saving animals or finding a stranded hiker—the less they will be feared. "While there is potential for this technology to be misused, its potential for improving our understanding of the natural world, … improving endangered species conservation, outweighs the risk of some bad actor using it for evil purposes," he says. "That would happen anyway."