Shocking control: wild gray wolves and shock collars

Female wolf in Wisconsin © Tim Wilder

The first time I heard someone discuss using shock collars as a control technique for wild wolves, I thought it must be a really bad joke. Only, it wasn’t. It fell squarely under the heading of “aversive conditioning” a school of thought aimed at devising ways to keep wolves where we humans want them to go — and, quite arguably, keeping wolves alive. But before I touch on the most recent paper to be published on assessing shock collars for controlling gray wolves, let me back up a few steps and explain a few different reasons why people are considering this seemingly extreme measure.

Conflict is typical, perhaps inevitable, at the interface of gray wolf territories and agricultural settings where domestic livestock are grown… and this conflict typically stems from wolves killing cattle, sheep, guard dogs, horses, mules or other livestock animals. (Or, you could say it stems from ranchers failing to prevent these attacks… though the end result is still death and a loss of money or property on the rancher’s part.) In an effort to increase tolerance for wolves on the landscape, many researchers and wolf advocates have tried to devise various measures to deter wolves from preying on livestock or getting near ranches or farms. Lethal measures, such as outright shooting wolves, don’t go over well with the environmental crowd. (And when the wolf populations are small, as with the Mexican gray wolf’s, lethal measures simply are not scientifically sound.) Though when I interviewed ranchers, many said that in a situation where a pack was continually hazing their cows, if they could just shoot one of the wolves, the rest in the pack would “learn not to go near” their ranch. Perhaps this is true, because wolves are incredibly smart animals. But it’s just not logical when there are only 45 to 55 of the wild animals in the entire U.S. at any given time (as is the case with Mexican grays, there are substantially more gray wolves in the northern Rocky Mountains and Great Lakes region). So, what else can be done to control wolves non-lethally, and yet also appease ranchers and concerned citizens in or near reintroduction sites?

Non-lethal control measures include hazing wolves with cracker shot, sirens, bright lights, and so on. But these measures are limited in time and space. Cracker shot requires a person to be present guarding the livestock at all times, not to mention a little skill in angling it so that it explodes above the wolf, not near it or on it. And some wolves grow accustomed to the fireworks show after repeated exposures. The same with bright lights and sirens, though these at least have the option of remote control which frees a person from having to be present all the time. Yet all of these are point-source measures, meaning they do not work well over wide areas and they result in the need to confine livestock to small areas for protection — which is not feasible in many areas, especially in the arid southwest where the forage per acre is much lower than in Idaho, Montana or Washington. Fladry works well over greater acreage, but may be time-limited in its effectiveness, once wolves learn to test he visual barrier. Adding an electric current to the fladry (called “turbo-fladry”) greatly extends the effectiveness. But there is still an up-front expense to the ranch operator with installing any of these systems. But what if we could condition wolves to avoid certain site-specific swaths of land or ranches? That would be best for both man, beast and livestock — right? Well, theoretically, perhaps.

Which is where Hawley et al. come in. They recently published a paper in the Journal of Wildlife Management assessing the value of shock collars on wolves as a deterrent for livestock depredations. {1} “Depredation” is just a fancy way of saying that a wild animal injured or killed a domestic livestock animal that holds monetary value to its owner. Theoretically, the value of shock collars is that they could conceivably be a diffuse-source, non-lethal control measure that covers wide areas, because they stay physically with the animal as it roams during the conditioning phase, and they ultimately change the animal’s everlasting behavior after the collar is removed (like I said, theoretically). But a major argument against shock collars is whether or not the time-limited conditioning provided by shocking events will actually carry over into a learned behavior once the collar is removed. (That is to say, this is the major argument if you can tolerate the idea of shocking wild animals at all.)

Hawley’s team found that the curbed behavior exhibited while wolves wore shock collars did not extend over time once the wolves were sans their lovely urban jewelry. They note early in the paper that Great Lakes residents support gray wolf recovery “but support could change if human–wildlife conflicts continue to increase.” Therefore, their goal was to determine whether or not shock collars offer a viable way to teach wolves to avoid livestock pastures, or site-specific areas, thereby eliminating the age-old wolf-livestock conflict and increasing tolerance for wolves on the landscape. Hawley’s team also took cues from previous experiments with captive coyotes that reported favorable results, and captive wolves that reported inconclusive results. Theirs is the first to test this non-lethal method with wild wolves though.

Their experiment was confined to a 9,000 square kilometer area in northcentral Wisconsin that they describe as 64 percent forested and a combination of private, public and timber lands criss-crossed with paved and dirt roads. In short, it doesn’t sound like pristine wilderness, but rather like a typical urban-wildlands interface with mild to moderate disturbance and human presence. The team relied on external estimates of about 40 wolf packs composed of 3.5 individuals each (which sounds an awful lot like a mated pair with young of the year), and they say that the agriculture in this area is mostly soybean, cranberry and potato production with livestock operations. Now that we have a feel for the context of the land and human activities, let’s take a look at what they did.

Their total sample size was 10 carefully selected wolves, each wolf selected from a different pack. They excluded young pups and wolves with health issues, and used mostly wolves that had previously been fitted with radio collars by the state natural resources department (if not previously outfitted, they received a radio collar). They divided the 10 into 5 control wolves and 5 experimental wolves. The experimental ones received a shocking device attached to a radio collar, or to a separate collar. They then identified suitable “bait” sites within the wolves’ territories, and placed road-killed deer within the site along with shock towers (devices that trigger the shock delivered via the collar) and data loggers that tracked each wolf within a 75 meter range. The shock towers were manipulated to pulse on 13-second cycles, so that a wolf entering the “shock zone” within 35 meters of the road-killed deer bait would receive a shock for 13 seconds, a rest spanning 13 seconds, and then another shock. This cycle was continuous as long as the wolf remained within the 35 meter zone near the deer carcass.

For both experimental and control wolves, they monitored the animals for 14 days (with bait) before activating the shocking devices, 14 days with the shocking device activated, and then 14 days with the shocking device de-activated. (They switched out the bait every two or three days.) Their results did not show a significant difference in the amount of time spent in the “shock zone” in the third time period after the shock collars were de-activated between the control and the experimental groups. In order to prove that the shock collars were indeed producing aversive conditioning, they would need to have demonstrated that the experimental wolves were spending significantly less time in the shock zone after their collars no longer delivered shocks when they crept near the deer carcass. There was however a difference in the amount of time spent in the shock zone during the time when the experimental animals were actively receiving shocks, which shows that the collars were an aversive control measure — albeit time limited, and wholly device-dependent.

One thing I found very interesting was that the author’s found that experimental wolves moved approximately 0.7 kilometers away from the shock zone center during and after the shock treatment. Hawley et al interpret this to mean that a buffer zone could be set up around shock-sensitive pastures to protect livestock during “sensitive calving season” — but again, this relies on a point-source protection and in the arid southwest, it is customary to not pen pregnant cows, and open-range calving occurs year round.

At the end of their paper, the researchers call for more research into the long-term effects of shock collars in aversive conditioning of wolves. But they assert that “Our results suggest that shock collars hold potential value for use as nonlethal control for free-ranging wild wolves in certain depredation management situations.” I think the phrase “certain situations” is very key here, because just as there is no singular approach to ranching, there is no singular approach to preventing depredation by gray wolves. Contextual factors such as the type of husbandry methods, distribution and abundance of livestock, ground-forest cover and degree of ruggedness all play a role in determining the best types of protection measures for livestock.

My entirely personal view is that shock collars are not a viable solution for practical reasons. I think it’s an interesting exercise to test, and I support the idea that they are seeking alternative non-lethal control measures, but this is not a practical solution on the ground for reasons of time and expense versus benefits. Plus, gray wolves are wild animals, not domestic yard dogs. And we as a society opted to reintroduce wild gray wolves. While I understand that the entire burden of wolf conservation should not be borne alone by ranchers, I do believe that investing resources in aiding ranchers to deal with wolves in other types of hazing, livestock husbandry methods such as range riders and — if it comes to it, compensation — are all vastly more effective uses of limited conservation dollars.

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NOTES and SOURCES:

I originally wrote this post in August 2009; but in switching over to using ResearchBlogging.org I needed to re-post it for their system to recognize it.  Thanks for your patience.

{1}
Hawley, J., Gehring, T., Schultz, R., Rossler, S., & Wydeven, A. (2009). Assessment of Shock Collars as Nonlethal Management for Wolves in Wisconsin Journal of Wildlife Management, 73 (4), 518-525 DOI: 10.2193/2007-066

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