Rodney Jackson has studied snow leopards for so long that he knows better than anybody how difficult they are to observe. Some 12 different countries that encompass the species’ range are all eager to learn more about the animals, including how best to conserve them. But information about the cats’ habits and range is elusive at best.
In the early 1980s, Jackson and his team placed snares along the ridgelines and the bases of cliffs where the animals usually liked to walk—information they gathered from paw prints, scrapes and urine sprays, which are ways that snow leopards communicate with each other. His team was the first to capture a snow leopard and fit it with a radio-telemetry collar. This helped them track the cat up and down the jagged peaks and valleys of the Nepalese Himalayas for the following months.
“Rodney took himself to Nepal when nobody else wanted to study the cat,” said Don Hunter, science director of the Rocky Mountain Cat Conservancy, who has worked on snow leopard projects with Jackson for decades.
That’s not to say the work was easy. Jackson’s team had to hike for two weeks just to get to their base camp in Nepal. “When we did our work, there were no [satellite] photos, no GPS, no digital camera traps,”Jackson said. Their only communication with the outside world was runners who would bring back information overland from Kathmandu every few months—a trip that itself would take days.
From there, the team spent days crossing passes usually 14,000 feet above sea level—sometimes as high as 19,000 feet on 30–40-degree slopes. “[The snow leopard] likes cliffs. It likes to stay high—it stays hidden,” Jackson said. They usually had to get the VHF receiver up to the top of a ridge so they could detect a signal from the collared cat somewhere in the surrounding valleys.
Decades later, Jackson, pictured above, no longer had to climb as many giant mountains—drones did the work for him. But he and his colleagues didn’t just watch snow leopards all day from their couches—the cat is just as hard to find using a bird’s-eye view because of its excellent camouflage. Instead, he and his team used the drones to search for argali sheep (Ovis ammon) and Siberian ibex (Capra sibirica), species that snow leopards prey on. This method helped them uncover snow leopard carrying capacity in a reserve in Mongolia.
“Since you can’t count the cats, our supposition is we can do a better job of counting their prey, and we can do a better job of seeing how the cats are doing,” Hunter said.
To help with their work, Hunter and Jackson enlisted the aid of Daniel Rice, who was then an undergraduate wildlife student working with the Geospatial Centroid at Colorado State University. Rice presented the team’s work at the 2024 TWS Conference in Baltimore, Maryland. They published the results of their research in the journal Snow Leopard Reports.
The Ikh Nartiin Chuluu Nature Reserve sits about 300 kilometers east of Mongolia’s capital, Ulaanbaatar. While scientists have only confirmed a few snow leopard sightings in the area in recent decades, snow leopard prey is a lot easier to come by.
Mongolian scientists had been surveying argali sheep and Siberian ibex there using traditional spot-and-count methods for some time. But rocky outcroppings dot the landscape and can hide ungulates from observers walking between them, said Rice, now a research technician with Colorado Parks and Wildlife. The snow leopard team decided Ikh Nartiin Chuluu would be a good place to test the new method using drones, counting the ungulates from the sky to see how well the numbers could correlate with traditional ground observers walking the same transects.
In 2019 and then again in 2022—the global COVID-19 pandemic interrupted the study—the team used drones equipped with GPS and thermal and color cameras. They ran a handful of flights the first year, then more than 40 in 2022, when they had improved drones and field-tested survey protocols.
Their project was nearly doomed from the beginning, as the drone crashed on the first flight. But the team didn’t lose hope. They continued flying drones to look for domestic livestock, ibex and argali sheep in the early morning when the thermal cameras are most effective. They ran the drones on a lawnmower-type pattern, flying them back and forth over 4-by-2-square kilometer sections that encompassed the traditional ground transects.
Back in the lab, Rice analyzed the images Jackson and Hunter captured in the field. He compared the positioning of the animals with the local terrain, predicting whether each drone sighting would have been visible from the ground or not due to the obstructive rock outcroppings.
While they had heard reports of recent snow leopard sightings in the Ikh Nartiin Chuluu Nature Reserve, they saw plenty of sheep and ibex—the snow leopard had left the area by the time they arrived. But still, the assumption is that the better the prey base, the better snow leopards are potentially doing in the area, Hunter said.
The drones were faster and more efficient at spotting ungulates, though. “Daniel found significantly more animals than we did,” Hunter said.
Based on Rice’s observations and visibility calculations, 14% of the ungulates they spotted by drone would not have been visible to ground observers at all. In fact, rocky outcroppings obstructed over 30% of the study area’s terrain from what ground observers would be able to see while walking the traditional transects.
Jackson said that transect and point counts are likely still reasonably reliable in areas both open and not too rugged. But much of the snow leopard’s range lies in highly rugged landscapes like the Himalayas. Here, it could take hours to get to the high points on ridges to make these point counts in the first place. In these cases, drones could be a major game changer, helping to reach high places more quickly, increase visibility and observe and track flushing animals.
Hunter said the team is planning to test the drone’s accuracy in more rugged landscapes for future studies. They are also still experimenting with different types of drones, especially as technology improves every year. The team will return to Mongolia this coming fall after more testing on pronghorn (Antilocapra americana), bighorn sheep (Ovis canadensis), and deer in Colorado—hopefully deploying a state-of-the-art fixed-wing drone.
But the differences between Jackson’s early days are tangible. Back in Nepal in the 1980s, Jackson worked off a government-provided relief map. He and his team overlaid the map with tracing paper, characterizing habitat types with the help of sighting compasses to give accurate locations.
“Now, you put up a drone and get a map almost immediately from your study area,” he said.
The ungulates are still only part of the story, though they made up nearly all of this research. But finding places like Ikh Nartiin Chuluu Nature Reserve with great prey bases means that at least there, “maybe we don’t have to worry as much about the cats.”
This photo essay is part of an occasional series from The Wildlife Society featuring photos and video images of wildlife taken with camera traps and other equipment. Check out other entries in the series here. If you’re working on an interesting camera trap research project or one that has a series of good photos you’d like to share, email Joshua at jlearn@wildlife.org.
