The tricky business of darting an elephant from a helicopter

Editor’s Note: This is part 2 in a 3-part series on helicopter operations in South Africa’s Kruger National Park. Follow the series at verticalmag.com/kruger. Our reporting was made possible with the support of Airbus Helicopters.

Sometimes a wildlife darting mission goes according to plan. Sometimes the wildlife has other ideas.

It has now been seven or eight minutes since the veterinarian in the back seat of our Airbus H125 helicopter, Dr. Peter Buss, took aim at the young bull elephant below us. It was a clean shot, delivering a cocktail of thiafentanyl, an opioid, and azaperone, a tranquilizer, into the animal’s hindquarters.

SANParks helicopter with elephant in Kruger National Park
A SANParks H125 helicopter manages an elephant that has just received a tranquilizer dart to its flank. The time between when an animal is darted and when it falls asleep is critical for both the safety of the animal and the success of the mission. Lloyd Horgan Photo
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At the doses contained in the dart, the drugs usually take full effect after 10 minutes. That’s a problem, because with just a couple of minutes left on his feet, this young bull is being stubbornly uncooperative. Pilot Brad Grafton is doing his best to urge him into a clear area, but the elephant seems impervious to our rotor wash. Instead, he keeps stumbling through the bush towards a tourist road in Kruger National Park, where a handful of safari vehicles have pulled over to watch the show.

Finally the elephant pauses next to a small dead tree. He sways a little on his feet, then tips over on his side, bringing the tree down with him. It’s not the outcome Buss had hoped for.

Grafton lands the helicopter and Buss jumps out to join his ground team, who are already at the elephant. They won’t be able to perform their research tasks on this one — his awkward position across the tree puts him at risk of injury, so it would be unwise to leave him there for long. Buss administers an antidote and returns to the aircraft. We lift off in time to see the elephant wake up and heave himself to his feet, then amble off, apparently unconcerned. Across the radio comes a general sigh of relief.

Fortunately, the next elephant that Buss darts is much more tractable. He submits readily to Grafton’s herding, finally passing out next to a dirt road that’s far from the prying eyes of tourists, yet readily accessible to the ground crew. Grafton locates a clear patch of veld and lands again, this time shutting down. The veterinary team’s work is about to begin.

Safety first

Few helicopter missions are as challenging or rewarding as wildlife darting and capture — both from the perspective of the pilot, and the person with the dart gun in the back.

“The big thing about darting wildlife is it looks fairly simple and straightforward, but it’s got multifactorial components to it to make sure that it’s successful,” said Buss.

For the South African National Parks (SANParks) veterinary team, the first challenge is in formulating a chemical concoction that packs enough punch to immobilize a 10,000-pound (4,500-kilogram) animal, while still fitting in a dart with a maximum volume of three milliliters. According to Buss, the powerful, potentially deadly mixture of thiafentanyl and azaperone is the only thing that fills the bill, and “we have to be very careful with how we, as humans, use it.”

Then there’s the matter of delivery, which requires a steady aim and clear communication with the pilot. From that point, said Buss, “you have to be very careful about how you manage that animal in terms of limiting the risks to them. So, for example, you don’t want to chase them too far, because they’re not endurance animals, these things.”

For the pilot, that process of managing the animal is a balancing act — knowing when to move in and when to back off. “You’ve got a bit of a goal that [you] set yourself, and that is to try to get the animal close to the ground crew and in safe proximity,” explained SANParks chief pilot Grant Knight.

Veterinarian Peter Buss darts an elephant from a SANParks helicopter
“Pretty much all our work, particularly in the field, particularly with the large mammals, is done with the Air Wing. We pretty well can’t do without them,” said Peter Buss, shown here darting an elephant. Lloyd Horgan Photo

Yet at the same time, the pilot can’t become so fixated on this goal as to lose situational awareness. Maneuvering so low to the ground leaves no room for error, and even a surly, drugged-out elephant can’t be allowed to distract from the branches waiting to snag the tail rotor.

“You’ve always got to take a step back and realize you’ve got a tasking that’s flying safe; keeping the aircraft, the crew safe, and the guys on the ground safe,” said Knight. “It’s just important to always keep safety as the highest profile within your operation” — even if that means having to wake up an anesthetized animal and try for a different one.

An essential tool

Chemical immobilization is a vital tool for SANParks’ conservation missions, and one that is used regularly in Kruger National Park for a variety of large mammals.

With rhinos under particularly intense pressure from poaching, SANParks established the Black Rhino Guardian Program to understand the most vulnerable rhino population in the park. According to the program’s coordinator, Cathy Dreyer, “In order for us to get to know them, we needed to be able to, on an individual basis, tell the animals apart. And the only way that we could reliably do that was to ear notch animals. So that means immobilizing the animal, and once it’s darted by a vet and down, we give it a specific ear pattern.”

As of October 2018, more than 50 black rhinos in Kruger National Park were individually identifiable by ear notches.

Researchers collect data from an elephant in Kruger National Park
Researchers collect as much information as possible while an elephant is anesthetized. Because of the time and expense involved in darting each animal, it only makes sense to take full advantage of the opportunity. Lloyd Horgan Photo

“We’ve also fitted a lot of animals with satellite collars, to be able to get an idea of what the movements are, the seasonal movements, distances they’ve covered, what are the sizes of their home ranges,” Dreyer added. “And those collars required, again, that the animals be immobilized.”

Chemical immobilization is also used to recover young animals — whether black or white rhinos — that have been orphaned by poaching incidents. Once sedated, very small calves are sometimes loaded directly into the helicopter and flown to an orphanage outside the park’s boundaries, while larger animals may be slung out by their forelegs, or loaded into crates and trucked to bomas to grow up in safety.

“The really small ones don’t have a very long time,” Dreyer pointed out. “If they are really tiny and they are left out for a day or two, between the lions and the hyenas, they’ll often have horrific injuries or they’ll be taken out before you actually have a chance to recover them. So you need to get to them really quickly.”

In service of science

The elephant darting that took place during our visit was in service of several research projects, approved by committees well in advance. The primary research objective was to study how the sedative drugs themselves affect the elephants physiologically.

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“By that we mean, how does their respiratory function change, how does their heart function and blood circulation change?” explained Buss. “Once you understand that, you can start saying, OK, what are the interventions that we need to put in place to reduce the risk to the animal? [And] not only reduce the risk to the animal, but make sure that you don’t increase the risk to the people working with them — because obviously what you don’t want is an animal suddenly waking up or getting up when you have lots of people around them.”

SANParks researchers on ground with elephant in Kruger National Park
Treating individual free-ranging animals for a disease like tuberculosis is nearly impossible, so the aim of SANParks’ TB study is to better understand its prevalence in the wild population. “Our interest really is to see how the system responds,” said Peter Buss. Lloyd Horgan Photo

A secondary research goal was to screen the elephants for tuberculosis (TB). This bacterial disease is widespread in water buffalo within the park, but it hadn’t been seen in elephants until two years ago, when the necropsy of a dead elephant here revealed that the animal had suffered from advanced TB.

“So the question then was, how big a problem is this?” Buss said. “Which sounds fairly simple, but the procedures that we use, we’ve had to develop in order to do [the study].”

One of those procedures is a bronchial wash, in which sterile fluid is pumped into the animal’s bronchial tubes, sucked back out, and stored for later laboratory analysis. “The point being that if the elephant has got active TB and has lesions in its lungs and they’re shedding organisms into their respiratory tract, then by putting the fluid in and sucking it back out you hope to recover those organisms,” Buss explained. His teams performed similar washes of the elephant’s trunks, “because the trunk essentially is just another component of the respiratory system.”

According to Buss, the extensive preparatory work involved with this type of research means that the actual darting of animals in the field is just a small part of his responsibilities. But he said it’s also the most enjoyable aspect of his job, and his aerial vantage point is part of that.

“We are very fortunate that we do have helicopters to support us, so you get this totally unique perspective on the Kruger park, and the national parks that we work in,” he said. “It’s fantastic to be out there in that sort of environment.”

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