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A Lithuanian carp bait machine, peanut butter and drones all have something in common — the inoculation of prairie dogs against a deadly disease, sylvatic plague.

“It’s been a lot of fun and innovation coming up to these obstacles,” said Randy Matchett, wildlife biologist for the U.S. Fish and Wildlife Service at the Charles M. Russell National Wildlife Refuge.

Matchett is one of several MacGyver-like geniuses who have cobbled together a way to dispense a vaccine to prairie dogs across rugged landscapes like the CMR’s badlands in Eastern Montana. MacGyver was the 1980s television character — revived in a new CBS show — known for solving problems by making things out of ordinary items.

“We refer to it as noodling sessions,” said Kurt Kreiger, owner of the Billings company Model Avionics. “We’re all MacGyvers in our own right.”

Vaccinating prairie dogs against the plague is important to the U.S. Fish and Wildlife Service as it tries to restore endangered black-footed ferrets to the West — a species once-thought extinct until a small group was discovered in Wyoming. Prairie dogs are the ferrets’ main food source and also dig the burrows in which ferrets live.

“The one thing I’d like to highlight is that innovation has been an important ingredient in the recipe of black-footed ferret recovery…,” said Kristy Bly, a biologist for the World Wildlife Foundation, in an email. “From initial captive breeding attempts to rescue the species from extinction and reintroduction techniques to improve survival to tracking their movements and developing vaccines to protect them and their prairie dog prey from sylvatic plague, innovation is why black-footed ferrets exist in the wild today. Delivery of the sylvatic plague vaccine by drone and all-terrain vehicle is just another example of the legacy of innovation our partners in ferret recovery began 52 years ago.”

Flying service

Drones, also known by the less militaristic term unmanned aerial vehicles, are multi-rotor aircraft run by batteries. They’ve quickly gained the public’s attention for their ability to carry digital cameras aloft for video as well as still photography. But they’re also being used in agriculture and law enforcement with attachments like infrared cameras.

Kreiger volunteered for the prairie dog project after his wife heard about Matchett’s work during a radio newscast. She alerted Kreiger who, after making several phone calls, finally connected with Matchett.

“I’m pretty sure they thought some whacko was calling,” Kreiger joked.

The two met at a Billings gas station when Matchett was passing through town and immediately “clicked on ideas and inventions,” a back and forth process that led to this fall’s first drone distribution of a marble-sized vaccine pellet to prairie dogs.

At the same time the group developed an ATV-mounted tool to disperse the same vaccine-laced baits in three directions every 30 feet. Using the system the crew was able to treat about 50 to 60 acres an hour, the dispenser automatically firing as the driver cruised along transect lines in the prairie dog colony.

With the new vaccine distribution systems the scientists found that they were vaccinating about 70 percent of the colony.

“On an ATV we can treat a lot of acres, that’s a fallback,” Kreiger said. “It’s just not as much fun as flying stuff around.”

Matchett based the first ATV dispenser on a paintball gun, which uses compressed air to propel a projectile.

“One problem we had was dialing the system down low enough so it wouldn’t shoot the bait through a wall,” Matchett said, and laughed.

The crew also looked at catapult and slingshot-type bait throwers before Matchett and Kreiger devised a thrower like those used in tennis ball and baseball-throwing machines — a couple of spinning wheels sends the pellet flying.

If the UAV technology can be perfected, Matchett and Kreiger are hoping that about 300 to 400 acres an hour could be treated with vaccine, and without the intrusiveness of an ATV and the toll on a driver riding over bumpy, bouncy terrain.

“The whole key is to get the acres per hour up and be as accurate as you can,” Kreiger said.

Right now the machine can shoot one pellet every second while the drone flies at 20 mph. Doubling that amount would add speed and efficiency.

Part of that calculation is finding a way to balance the weight of the pellets and craft — about 18 pounds of payload — with flight time that’s restricted by batteries that hold a charge for only about 24 minutes. Increase the weight and the batteries drain more quickly.

“We have to try to find that sweet spot,” Kreiger said.

Other options considered were a gas-powered remote-controlled helicopter, which is harder to fly, and small gas-powered planes, which need an 80- to 100-foot takeoff and landing area.

“That’s a tough commodity to find in the prairie,” Kreiger said.

Plus, the entire project is on a tight budget since it’s mostly funded through a grant from the World Wildlife Federation. Helicopters aren’t cheap, a basic unit costs about $5,000.

“We’re trying to stick to off-the-shelf parts that are easy to come by and cheap,” Matchett said. “A lot of the ferret stuff has been that way.”

Carp bait

The aerial distribution has run into another problem, as well. The pellets containing the vaccine are not perfectly round, which can clog up the drone’s pellet thrower. That’s the problem Kreiger is working on now.

This all goes back to the Lithuanian carp bait machine, the BoilieRoller. Matchett discovered the machine while searching the internet for a way to make the vaccine-laced baits. He found candy makers and an interesting video on marbles, but it was the bait machine that made the most sense.

In Europe, where carp fishing is a huge pastime, making carp baits has generated a cottage industry of bait-making machines, including the BoilieRoller.

By mixing up flour, peanut butter for flavor, blue food coloring since prairie dogs can see blue, and the vaccine, scientists and volunteers assisting the USFWS have created a dough recipe. The dough is squeezed through a caulk-gun type device that produces a rope of dough. Run the dough through the BoilieRoller and you have pellets.

Using the recipe the crew made 300,000 pellets in two months at a Fort Collins U.S. Department of Agriculture lab.

The only problem is that when the pellets are drying they develop flat sides, creating an almost mini-marshallow-like pellet rather than one that’s completely round. That has led to the equipment jams that Kreiger, Matchett and others are working to resolve.

“It’s turned out to be a heck of a challenge,” Kreiger said.


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