GA Serves America: Aerial Animal Tracking

Pilot Roger Stradley likes to take off early during the summer months—usually before 6:30 a.m. The air is smoother then, and he’ll be able to get more accomplished before the inevitable afternoon winds and thunderstorms batter his tiny Piper Super Cub. Flying low over the foothills rising to Swan Lake Flats in Yellowstone National Park, he keeps an eye on the terrain as he scours the ground looking for wildlife. He is about to turn the airplane around when he sees a solitary wolf in the middle of a small clearing looking up at the airplane. Unafraid, the animal gives Stradley an insouciant look before sauntering into the shelter of the trees. Stradley exhales deeply. Even after more than 40 years of spotting wildlife, he never gets blasé about seeing magnificent creatures.

Stradley has one of the most varied and enviable jobs in aviation: wildlife spotting and tracking for a variety of state, federal, and tribal agencies, helping biologists to keep track of wolves, bears, elk, moose, beaver, buffalo, and even fish. Flying low and slow over some of the most spectacular scenery in the world, Stradley has seen things most people cannot imagine. He’s seen a pack of wolves face down a family of grizzly bears, a flock of 1,000 swans suddenly take flight off of a lake, and a giant herd of elk filling an entire valley as it made its way to the high country for summer.

One could say it was a job he was born to do. His father, Jim Stradley, conducted the first aerial wildlife surveys inside Yellowstone National Park during the late 1940s, counting elk and bison herds. Naturalists would later use his logbooks to construct a historical record of herd sizes and movements. Roger’s earliest memories are of flying with his dad. “Dad would put me in the front seat and have me fly all over the sky,” Stradley said. “Of course, I couldn’t reach the pedals so he’d have to work those himself.”

Stradley accumulated 500 hours of flying time with his father before he soloed.

Jim Stradley took up flying in the 1930s and, with the help of his wife, Margaret, ran the airport in Sand Point, Idaho, giving flying lessons, offering charters, and doing whatever he could to fly and earn a living. When World War II broke out, Jim signed up for the Army Air Corps and was shipped to Bozeman, Montana, where he taught cadets basic flight training at Belgrade Airfield (now Gallatin Field).

After the war, Jim decided to stay, and moved his wife and two boys, Roger and David, to Bozeman. A rugged, profane man, Jim seemed like a character straight out of the Smilin’ Jack cartoon series, a guy so at home in an airplane that he didn’t get into it as much as put it on in the morning with his overalls. Among his many flying jobs, Jim delivered the local newspaper, tossing them to remote ranches from his 65-horsepower Taylorcraft.

Flying was the family business, so Jim made sure both his sons learned to fly. And he had some unique teaching techniques. He would take students up in an old Waco biplane, roll it inverted, and then tell the student to fly back to the airport—upside down. He’d take his boys up at night and have them do unusual attitude recoveries in the dark and without an attitude indicator. He’d have them fly cross-country at night, going from ranch-house light to ranch-house light, which was fine, provided you knew the terrain in between. His dad, Roger says, “insisted that we know the terrain like the back of our hand.”

Between himself; his father, who died in 1991; and his older brother, who retired several years ago, Roger says the Stradleys combined for a total of 158 years of flying experience (and wildlife counting). Like his father, Stradley has done a little of everything. He flew agricultural aircraft, charters, both flew and repaired helicopters in Vietnam, was a flight instructor, flew air attack in wildfire operations, did helicopter long-line work, and flew gliders. He is also a licensed mechanic and avionics technician. In all, he’s logged more than 62,000 hours of flying time. That’s the equivalent of more than seven years of continuous flying.

Stradley figures he has committed to memory the terrain within a 300-mile radius of Gallatin Field. That’s 282,600 square miles. He tells the story of a hunter who not long ago bagged a mountain lion. The hunter was stopped by a game warden, who asked the hunter where he shot the animal. The man proudly pulled out a snapshot of some hillside and named a location. The warden was suspicious, however. Mountain lion permits are strictly controlled, and something about the man’s explanation wasn’t right. He asked to borrow the photograph.

He then took the photograph to Stradley, and asked if he recognized the place in the photo. Stradley said maybe, and asked the warden to hop in the airplane. After taking off, Stradley flew the opposite direction from the place the man claimed to have shot the lion. After about a half hour of flying, Stradley pulled in low over a hill, turned a corner, and asked the warden, “There, is that the tree stump in the photograph?” It was.

No, Stradley didn’t know about that exact stump, but from the photo he recognized the terrain and vegetation and knew exactly where to look. The warden drove back to the place, and took a photo from the exact spot that the other picture was taken. He then took the two photos to the hunter and asked him if the two photos were the same. The man conceded that, yes, they were. Well, then, the warden said, “You’re under arrest.”

On site

“You lookin’ for Roger?” asks the fresh-faced kid behind the counter at Gallatin Flying Service in Bozeman. “He’s in his office,” he says, pointing at a door. Through the door is a large office. The walls are covered with commemorative plaques, news clippings, old photographs, and maps. In one corner there’s a lounge chair. In another, a big desk covered with Post-it notes and what appears to be several months worth of accumulated dust. But no Roger.

Through a doorway covered by an old painter’s tarp is the hangar. Inside is Stradley’s real office, a bright yellow 1956 Piper Super Cub. Wedged in beside it are two others, also Stradley’s: another 1956 model and a recently rebuilt 1967 model. There’s an old engine block on the floor, and a couple of long workbenches are covered with tools and airplane parts. The rafters are jammed with spare wing and tail sections, along with the pieces of an old glider. Along one wall, there’s an array of what appears to be old TV aerials.

“Welcome,” comes a voice from behind me. Out steps Stradley. A sprightly septuagenarian with bright blue eyes and a shiny, bald pate (“My best feature,” he jokes), Stradley wipes his hands on a rag and gives me a quick tour of the place. In contrast to his father, Stradley has a gentle, reassuring manner—more country doctor than daredevil pilot. The airplanes, he explains, are flown by himself and his two assistant pilots, Steve Ard and Neal Cadwell, and are devoted pretty much year-around to fish and game work. The aerials are different directional antennae used to track various wildlife—different frequency ranges for varying species. As Stradley flies, a researcher sits in the back of the airplane and operates the antenna, which is attached to the underside of the airplane, turning it 180 degrees until the distinctive set of tones and pulses emitted from a particular animal’s radio collar are picked up and its proximate location determined. It’s old technology, but effective, Stradley says. Newer, GPS-based transmitters are available, but at a cost of $3,000 apiece, it gets expensive when they are lost or damaged.

Right now, however, we’re in a hurry. Thick clouds are lapping over the tops of the Tobacco Root Mountains to the northwest. A storm is headed our way. If we’re going to fly, we better go right now.

After taking off from Runway 3 at Bozeman, Stradley climbs to about 200 feet agl—about as high as he ever gets—and heads northeast into the foothills of the Bridger Mountains. He flies up a ridgeline, following a series of narrow trails scratched into the side of the grass-covered hill by a herd of elk making its way to summer pastures. Stradley has sharpened his sense of where to find wildlife. If a herd has strayed from its usual territory, or if its composition has changed, he notices. If an animal is sick or injured, he can tell.

“There,” Stradley says, pointing to a large group of elk sheltered in a stand of pine. The animals, mixed in among the trees, are not easy to see. Stradley passes low overhead, herding the animals out into the open. He then circles around—once, twice, three times—and then gives me a number: 209. That’s not about 200, but exactly 209. Stradley can further break it down into the number of bulls, cows, and calves. The park service requires exact numbers, Stradley explains, to check on the size of the herd, its health, and its general trends. Among other things, the numbers are used to calculate the number of hunting permits to issue for the upcoming season.

The ability to count large herds of animals out in the open from an airplane moving at 80 miles per hour is a bit like counting grains of sand moving through an hourglass. It’s an art that takes time and practice. Most of the techniques, says Ken Hamlin, a research biologist with the Montana Fish, Wildlife, and Parks Department, were developed by the Stradleys. “They taught us a lot of the tricks.” One is to visually break the herd down and count by groups of 10. If he has to, Stradley will circle overhead for an hour or two until the count is completed. In some cases, where the size of a herd is simply too large to be counted on the fly, they’ll take a photograph and make a count using it.

Old-time biologists used to do things on horseback, Hamlin says. The use of tracking radios and aircraft revolutionized the business. In addition to giving a three-dimensional picture of the situation, they allow for much more work to be done. Depending on the season and location, Stradley may be spotting or tracking elk, deer, bison, antelope, bear, mountain lion, eagle, sage hen, crane, geese, swan, beaver, prairie dogs, or trout (using a capsule-sized radio transmitter implanted in a fish). Basically, Stradley says, “Anything that walks, flies, or swims.” He even tracks humans, flying along rivers counting fishermen—or at night, lights off, looking for poachers using spotlights.

His proudest work, however, has been with the Wolf Restoration Project. He was one of the original pilots when the program started in Yellowstone in 1994. Its success has helped to remove the animal from the Endangered Species List. “You cannot study wolves without aircraft,” says Douglas Smith, leader of the project. Stradley, he says, is one of a handful of pilots who can do the work, not only because of his flying skill, but because of his knowledge of the terrain and understanding of the animals themselves. “Roger has a better idea than a lot of our biologists of where to find these animals.” Not only that, but Stradley will fly seven days a week if he needs to. “He’ll call me on Christmas Day and say, ‘Doug, the weather’s good. Let’s go,” Smith says. “We’re lucky to have him.”

Stradley’s work with wolves has gained him a small measure of celebrity. It has been featured on CNN and the Discovery Channel, as well as an IMAX movie on wolves. In one bush pilot video, he demonstrated how to recover from a “moose stall,” in which pilots have inadvertently stalled their airplane while circling over an animal. At low altitude, there might not be enough room to recover.

As the number of wolf packs grew and the population expanded, now at more than 1,500, Stradley has followed the animals as they have moved beyond the confines of the park into the neighboring states of Wyoming, Idaho, and Montana. He flies more than 600 hours a year just tracking wolves, and he has come to know some of the animals by sight. In addition to tracking and spotting, Stradley assists in tagging operations, in which an animal is shot with a tranquilizer dart in order to have a radio collar put on or removed, or its health checked. Stradley will first spot the animal, then circle overhead and direct a helicopter into the area carrying the rifleman (the sound of an airplane engine doesn’t seem to bother the animals but the sound of a helicopter does). During all of his flights, Stradley uses Automatic Flight Following, a GPS-based tracking service for government contract aircraft.

On our flight back, Stradley flies through a deep canyon, circling over the rocky ledges looking for mountain goats. He sees tracks, but no animals. He then heads out into a broad river valley, skimming the tops of the cottonwood and willow trees. He points out a variety of bird species: sandhill cranes, pelicans, osprey, cormorants, gulls. He turns above a tree. High in the uppermost branches, a bald eagle sits on a nest. Stradley circles a couple times, tying to count the number of eggs in the nest—another one of his jobs—then it’s back to the airport.

Stradley has an enduring appreciation of nature. He finds himself stopping on the side of the road on the way home sometimes just to watch a herd of pronghorn tear off across the prairie, or a pair of gulls try to scare off a hawk hovering over their nest. But flying is still his first love. “I never get bored. It’s something new, something different every day.”

Tom LeCompte is a freelance writer and pilot living in New England.