The Sylvatic plague, a bacterial disease transmitted by fleas, is threatening to wipe out prairie dogs, the primary prey of the black-footed ferret, itself an endangered species. The United States Fish and Wildlife Service (USFWS) wants to use drones to vaccinate thousands of prairie dogs so ferrets have ample food to survive.
North America’s only native ferret species has been endangered since 1967, according to the USFWS. Prairie dogs can make up almost 90% of the mammal’s diet. Since 2008, all captive-born ferrets have been reintroduced to the wild after being injected with the vaccine, according to the National Wildlife Health Center. With only 300 ferrets left remaining in the US at the end of 2015, protecting the animal at risk isn’t worthwhile if its food source is jeopardized: Once it spreads in an area, the plague can wipeout close to 98% of the prairie dog population within a matter of weeks, USFWS’s supervisory wildlife biologist Randy Matchett said in an interview.
To fight the spread of the disease among prairie dogs, the US government is planning to use drones to scatter vaccine-laced M&M-like medicine at a ferret habitat in Montana. Park officials at Montana’s UL Bend National Wildlife Refuge, expect that the drone delivery of the Sylvatic Plague Vaccine (SPV) will “eventually be the most efficient, effective, cost-conscious, and environmentally friendly method of application,” according to an environmental assessment from March 2016. The system will be operational by Sept. 1 if the US Fish and Wildlife Service approves it, the Guardian reported.
Although the vaccine has been around since the early 2000s, the US government is establishing new ways to administer it to larger areas. Developed in-house by the United States Geological Survey (USGS), the model of the bait was originally used to make biodegradable fishing lures. Water, peanut butter, and vaccine were added to it, Matchett said.
Until now, SPV has been applied by hand, uniformly dropping single baits every 9 to 10 meters for prairie dogs in the wild. Around eight acres can be covered in an hour of walking, Matchett said. However, covering the target area of 1,200 acres is unimaginable with a small crew of people. With drones, it will take around 50 seconds to cover one acre.
The next step is to design the appropriate apparatus to deliver these half-inch, chewy medicines, which will be mounted on the drones. Matchett outlines two possible ideas: In one design, the dispenser will be comprised of an upside down jar, filled with vaccine pellets, with a rotating lid. Cavities on the lid will be spaced to drop the vaccine at uniform intervals. In another version, the dispenser will shoot the vaccine 30 feet to the left and to the right, depositing 30 baits simultaneously. With multiple baits dispensed at once, a drone could be capable of treating 400 acres in an hour.
“It’s still a work in progress, but we’re hoping for success,” Matchett said.