It seems logical that when wolves prey on cattle and sheep, the solution is to ‘thin out’ the pack. But new research suggests exactly the opposite: Fewer wolves equals more dead livestock.
An interesting story appeared recently in The Seattle Times concerning ranching in Washington state.
The story detailed some unusual behavior among cattle being raised in central Washington’s Kittitas County, a lightly populated area that stretches from the Cascade Mountains in the west to the semi-arid rangelands along the Columbia River in the east. Bill Johnson, a ranch hand, was driving some cattle up a canyon, when, to quote the story, “a black cow wheeled and lunged at Johnson’s border collie, Nip.”
Before wolves returned to the area, that kind of behavior was rare, Johnson told the newspaper. Now, cows aggressively confront any canine that gets close to their calves. “It’s a sign that the wolves have been probing the cattle,” he said.
Johnson is participating in a project called Range Riders, which tries to prevent wolves attacking cattle by using signals from their radio collars to track the location of resident wolf packs. With funding from Conservation Northwest and the Washington Department of Fish and Wildlife, the project allows ranchers to hire seasoned cowhands to watch over their herds and monitor the wolves.
“We wanted to work with ranchers to give them the best possible tools for nonlethal deterrence,” Jay Kehne of Conservation Northwest told The Times. Kehne said that seven ranch families around the state signed up and each received up to $9,000, money the conservation group raised from donors. Fish and Wildlife officials also provided 41 ranchers to with $300,000 in subsidies to pay for range riders, automated lights, sirens, guard dogs and special flagging for pens to discourage wolves from attacking livestock.
Wolf predation is a reality now, ever since the animals began making a comeback in Washington some 20 years ago. The state is home now to at least 68 wolves in 16 known packs.
Of course, many ranchers would just as soon wipe out all wolves, and to be fair, they have sustained livestock losses. Wolves have killed three cows and a calf in Stevens County in the northeast corner of the state this summer, and last year, a sheep rancher in the same area documented 26 wolf kills and a loss of some 200 animals believed to have been killed by wolves.
But a recent study conducted by Washington State University researchers at the Large Carnivore Conservation Lab came to a surprising conclusion: Turns out that it’s counterproductive to kill wolves to keep them from preying on livestock. That’s right. Shooting and trapping simply lead to more — not fewer — dead cattle and sheep the following year.
Writing in the journal PLOS ONE, WSU wildlife biologist Rob Wielgus and data analyst Kaylie Peebles determined that for every wolf killed, the odds of more livestock depredations increases significantly. The trend continues until 25% of the wolves in an area are killed, which then stabilizes the rate of livestock depredations.
Only one problem: A wolf mortality of 25% “is unsustainable,” Wielgus wrote, and “cannot be carried out indefinitely if federal relisting of wolves [as an endangered species] is to be avoided.”
In 1974, the gray wolf was federally listed and government-funded predator control efforts were used to keep wolves from attacking livestock. But due to population recovery, wolves were delisted in 2012 and sport hunting is now allowed, resulting in what Wielgus and Peebles called a “widely accepted, but untested hypothesis” that the more wolves that are killed, the better for producers.
To reach their conclusions, Wielgus and Peebles analyzed 25 years of lethal control data from U.S. Fish and Wildlife Service's Interagency Annual Wolf Reports in Montana, Wyoming and Idaho. They found that killing one wolf increases the odds of depredations 4% for sheep and 5% to 6% for cattle. If 20 wolves are killed, livestock deaths actually double.
That seems counter-intuitive, but there is an explanation, say the WSU scientists.
The reason is that taking out an alpha male or female “disrupts the pack’s social cohesion,” they wrote. “While an intact breeding pair will keep young offspring from mating, disruption can set sexually mature wolves free to breed, leading to an increase in breeding pairs. As they have pups, they become bound to one place and can’t hunt deer and elk as freely, [and] they turn to livestock.”
However, the threat to livestock cannot be ignored, and along with the Range Riders, other non-lethal efforts are underway in Washington state, and elsewhere, to minimize the potential for wolf kills of livestock, including:
· Removing the carcasses of animals that die from other causes
· Providing facilities, such as one built by state Fish and Wildlife officials in Ferry County where producers can drop off dead animals for composting
· Persuading meat-cutting operators to stop dumping bones and scraps in remote areas visited by local wolves
According to the newspaper story, Washington rancher Sam Kayser, who owns 500 head of cattle, was among the first to sign up for the Range Rider programs. As a result, he said he hasn’t lost a single animal to wolves.
“The wolves are here, and there’s nothing we can do about it,” Kayser told the Seattle Times. “I want to believe there’s room for all of us.”
As the Washington State University researchers concluded, “Although lethal control is sometimes a necessary management tool in the near-term, we suggest that managers also consider testing non-lethal methods of wolf control, because these methods might not be associated with increased depredations in the long-term.”
As I noted, it’s an interesting story.
Dan Murphy is a food-industry journalist and commentator