In their analysis, Treves and his colleagues found that fladry and guard dogs proved the most effective at keeping predators away from livestock.
However, no tool works, said Bean, without one important addition: people.
"Human presence is the single most effective deterrent to wolf depredation," said Bean. "Some ranchers place two herders with each sheep band in wolf country, if they have the people available."
These days he still has to contend with coyotes, but loses just one to three sheep every two to three years to a wolf attack.
But not every rancher wants to invest the time, money or personnel into nonlethal methods. In 2012, Washington used $76,500 of state funds to eliminate the eight members of the Wedge Pack. It's unknown how much it will cost to kill all 11 members of the Profanity Peak pack. (Washington Department of Fish & Wildlife did not respond to requests for an interview.)
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"If lethal control was unsubsidized on public lands, meaning the rancher had to pay [for it], the phone would be ringing off the hook in terms of people wanting to understand nonlethal methods and how to reduce depredation," said Bean.
In large parts of America, getting ranchers to adopt nonlethal strategies is a struggle. Ranching is part of their livelihood, a tradition passed down through the generations. And in an industry where profit margins are tight, trying something different might pose too large of a risk.
"In the US, some of these things are new to the livestock community because we wiped the country clean of wolves and folks have been ranching on wolf-free landscapes for a hundred years," Amaroq Weiss, West Coast wolf organizer at the Center for Biological Diversity.
It may take a while to shift the culture to nonlethal interventions, but knowing which methods are most effective is critical information for state and federal wildlife agencies.
Treves recommends that future experiments keep investigators themselves unaware of the control method used on a test herd. In other words, studies that analyze predation control should surpass both silver and gold and go platinum.