By Dr. Becker
Wolves are routinely killed in the US to preserve livestock owned by farmers and ranchers. But recent research suggests that this controversial practice actually may increase the probability that wolves will prey on livestock in the future.
The Washington State University study results were published in December 2014 in the scientific journal PLoS One,1 and they challenge the commonly held notion that the fastest, most efficient method for dealing with wolves that threaten livestock is simply to shoot them.
Wolf packs are multiplying throughout the western states, leaving dead sheep, cattle, and other animals in their wake. Two states now have designated wolf-hunting seasons to address the issue.
It’s inevitable that the new research will add more fuel to the long-standing controversy about how to deal with wolves. "The livestock industry, they're not going to be happy with this," said Rob Wielgus, a Washington State University ecologist and the study's lead author.2
A Schizophrenic Approach to Gray Wolf Management
By the 1930s, open season on gray wolves in the western US had led to their eradication. The animals were reintroduced in the mid-1990s with 66 individuals relocated to Wyoming and Idaho.
Since then the wolves have thrived, to the point where both government wildlife officials and ranchers have resorted to once again shooting them to protect livestock. By 2013, the wolf body count was over 2,000.3
In 2011, in five western states (Idaho, Montana, and parts of Washington, Oregon, and Utah), wolves were removed from federal protection under the Endangered Species Act, making it easier to shoot them. Idaho and Montana even added a wolf season for recreational hunters.
In 2013, hunters killed 356 wolves in Idaho and 231 in Montana, which dropped the population to around 600 in each state. In addition, in 2014 the Idaho legislature created a “Wolf Depredation Control Board” that critics believe will work to take the number of wolves down to just above the cutoff (150) that could again give the animals federal protection under the Endangered Species Act.4
But the question no one was asking was, “Does killing wolves really help protect livestock?”
Study Suggests Killing Small Numbers of Wolves INCREASES Livestock Attacks
Wolves returned to Washington in 2008, and grew to 13 packs by 2013. WSU’s Wielgus, who studies issues of predator control and is the director of WSU’s Large Carnivore Conservation Lab, evaluated a 25-year history of wolf killings and wolf attacks on cattle and sheep in Idaho, Montana, and Wyoming, which were the first three states where wolves were reintroduced.
What he discovered was that when a wolf was killed in, say, Idaho, livestock killings in Idaho increased the following year by 5 to 6 percent for cattle and 4 percent for sheep. And the number of livestock killed increased with each additional wolf that was shot. If 20 wolves were killed, livestock deaths doubled. The situation didn’t improve until over a quarter of the wolves in the state were killed in a single year. Only then did attacks on livestock begin to decline.
Wielgus suspects the reason more livestock are attacked when smaller numbers of wolves are killed may lie in pack behavior. Wolf packs are headed up by a male and female breeding pair. If one or both are killed, the pack often disperses. Several new breeding pairs are created from that pack, and an increase in the wolf population is the result.
According to the WSU study, livestock attacks decrease only after so many wolves have been killed that they can’t possibly replenish their numbers through reproduction. This actually falls in line with observations made of Yellowstone wolf packs. Packs inside the park, where wolves can’t be shot, are large and complex, and include individuals of varying ages living together, whereas wolf packs living elsewhere consist of just a breeding pair and their pups.
Wielgus believes his study results show that shooting wolves as a routine practice is “counterproductive and unsustainable.”5 Killing small numbers of wolves increases livestock losses, but killing enough wolves to reduce livestock attacks could drive wolf numbers so low that they end up back on the Endangered Species List.
According to the study results, if less than 25 percent of the wolf population is shot per year, livestock losses increase the following year.
Humane Solutions Exist (and Cost Less Than Sharpshooters in Helicopters)
Predictably, wolf conservationists have welcomed the WSU study results, while the livestock industry persists in its belief that the only way to protect cows and sheep is to kill the wolves that prey on them.
Jamie Henneman of Washington Residents Against Wolves, who is also a spokesperson for the Stevens County Cattlemen’s Association, believes the study results were predetermined to arrive at a pro-wolf conclusion because the research was supported by the State Legislature, which has supported increases in wolf populations.6
But Wielgus feels the anti-wolf groups aren’t really interested in serious wolf management.
“They just want to get rid of wolves,” said Wielgus. ‘Livestock lobbyists are pretty much vehemently opposed to my research, but in terms of hard science, it stood the test.” 7
In searching for humane solutions to the problem, Suzanne Stone of Defenders of Wildlife has worked with ranchers in Idaho on different ways to preserve sheep without killing wolves. Some of the things they’ve tried include:
- Monitoring the location of wolf dens to avoid grazing sheep in those areas
- Using guard dogs
- Increasing the number of herders
- Flashing bright lights to frighten off the wolves
- Encircling flocks of sheep at night with wire hung with strips of fabric
The money Stone and the ranchers have spent trying different approaches is less than it costs to send a shooter up in a helicopter. Even better, fewer than 30 sheep have been attacked by wolves in the last 7 years, and no wolves have been killed.