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Scientific
Classification of Wolves
Gray Wolves
Red Wolves
Ethiopian
Wolves
Wolf Prey and
Predation
 Yellowstone After Wolves
Depredation
Wolf Depredation
Depredation
on Livestock and Pets
USDA
Wildlife Services 2002 Report
USDA
Wildlife Services 2001 Report
USDA
Wildlife Services Summary
Defenders
of Wildlife Compensation Trust
Wolf
Depredation Control in Minnesota
Non-Lethal
Depredation Control-Does it Work
Are
Wolves Endangered
IUCN
Manifesto on Wolf Conservation
Federal
Process of Reclassification and the Endangered Species Act
(4 items)
Frequently
Asked Questions About Wolf Management
Methods
Used for Estimating Wolf Abundance
Human Perspectives
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by Liz Harper
Wolf depredation is a concern wherever wolves co-exist with livestock.
Lethal methods are most often used in response to depredation,
but several alternative methods have also been tried. These methods
include the use of guard animals, electric fences, sirens and strobe
lights, improved animal husbandry practices, wolf translocation,
electronic training collars, sterilization, diversionary feeding,
taste aversion and flagging ("fladry").
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Bill Paul installs a lighting and siren device
in an attempt to scare away depredating wolves.
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Guard animals, such as dogs and llamas, can be useful predator deterrents,
because they bond with livestock and help protect them by either
chasing away predators, or by deterring predators with their presence.
For example, llamas have an inherent dislike of canids and will
attempt to chase them away. They can also provide passive protection
by being alert to predators. A predator that has been detected may
leave the area. Although this may work well for coyotes and foxes,
because of the size and pack nature of wolves, llamas (as well as
guard dogs) are at risk of being killed by wolves.
Guard dogs have long been used in Europe, but their success depends
on the shepherding techniques in those countries. Shepherds remain
with the flocks and work with the dogs to protect the stock. In
the United States, where livestock often move unattended, guard
dogs have not been shown to reduce depredation by wolves.
Electric fences can be used to exclude predators; however, 6-7-foot-tall
woven-wire fences with electrically charged wires along the top
and bottom are required to keep wolves out. This may work well for
small barnyards or chicken coops, but for larger pastures, these
are costly to build and maintain. They also interfere with movement
of other animals such as deer and pronghorn.
Sirens and strobe lights may be placed around a pasture and set
to act at regular or irregular intervals or when a radio-collared
wolf is in the area (Radio Activated Guard box). They may reduce
depredations temporarily by scaring the wolves from the area, but
wolves can become habituated to these deterrents and ignore them,
or avoid them to enter a pasture. Once habituation occurs, depredations
may recur.
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Llamas are guard animals that are sometimes
tried in non-lethal depredation control. However, wolves have
killed some llamas, so it is not clear whether llamas will be
effective.
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There has long been a belief that wolves prey on livestock because
of poor husbandry practices. However, a recent study in Minnesota
could find no changes in animal husbandry practices that were certain
to prevent wolf depredations.
Moving wolves from areas where they are depredating is a technique
that is often useful in areas of low wolf populations. When wolf
numbers are high in an area, however, the depredating wolf may be
moved into another pack's territory and be killed as a trespasser.
Even in areas of low wolf numbers, translocation is often unsuccessful,
as depredating wolves often find their way home, or begin depredating
in their new territory.
The use of electronic training collars to teach predators to avoid
livestock has shown some success during preliminary studies in Wisconsin
and Montana. Researchers have used these collars to deliver a shock
to captive wolves when they approach cattle, in hopes that when
the wolves are released again, they will no longer kill livestock.
There may be a limit to the length of time this training keeps wolves
from depredating. Furthermore, this method is logistically difficult.
Sterilizing wolves may reduce livestock depredation by retarding
local wolf population growth and eliminating pups. (Providing for
pups is believed to be an important motivation for livestock depredations.)
Because tested sterilization requires surgery, this technique is
not viable as a widespread method. If sterilization were to be used
as a technique in the future, nonsurgical sterilization methods
would need to be developed.
Diversionary feeding, or providing an alternate food source for
predators, has been tested as a method to reduce predation in wild
prey. Diversionary feeding has shown limited success in increasing
calf-to-cow ratios and is expensive and time-consuming. This method
has not been tested to see if it could decrease livestock depredations
by wolves, and in fact, is discouraged.
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Guard dogs may be useful predator deterrents,
because they bond with livestock and help protect them from
predators by either physically chasing away predators, or by
passively deterring predators with their presence. However their
success depends on the presence of shepherds too.
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Taste aversion conditioning, a technique involving baits laced with
lithium chloride, has been used on several species to limit consumption
of food. It has been tested on wolves, but shows no promise as a
depredation control technique. The reason for this is that wolves
are trained to avoid the baits, but they are not trained to avoid
attacking and killing live animals.
The use of "fladry" or flagging, is an old European hunting technique
of hanging long rows of closely spaced flags to direct wolf movements.
It may hold some promise in reducing wolf depredations as wolves
may be deterred by the flagging. To be successful, flags must be
less than 20 inches apart and must touch the ground. When it was
tried around cows in Minnesota, the cows ate the flags! This technique
may be difficult to maintain on a large scale, and habituation by
wolves is probable.
Many of these methods show promise in reducing livestock depredations
under some circumstances, but none has been shown to consistently
prevent wolf depredations. On the other hand, most have not been
extensively tested on wolves. Perhaps combinations of several types
of deterrents or new techniques may prove beneficial in the future.
Liz Harper is the information
specialist for the International Wolf Center, and is finishing her
master's degree on wolf depredations in Minnesota, U.S.A. For the
last decade, she has worked on a variety of projects, including
the black-footed ferret reintroduction in Wyoming, the Minnesota
wolf project, and various projects for Minnesota's County Biological
Survey, the Smithsonian, and Moorhead State University, U.S.A.
References
Alternative capture systems and aversive stimulus applications for
managing predation; U.S. Department of Agriculture's Animal and
Plant Health Inspection Service's, Wildlife Services, National
Wildlife Research Center Web page.
Cluff, H. D. and Murray, D. L. 1995. Review of wolf control methods
in North America. L. N. Carbyn, S. H. Fritts, and D. R. Seip, eds.
Ecology and Conservation of Wolves in a Changing World. Canadian
Circumpolar Institute, Edmonton, Alberta. 491-504.
Coppinger, R. and Coppinger, L. 1995. Interactions between livestock
guarding dogs and wolves. L. N. Carbyn, S. H. Fritts, and D. R.
Seip, eds. Ecology and Conservation of Wolves in a Changing World.
Canadian Circumpolar Institute, Edmonton, Alberta. 523-526.
Eles. H. 1986. Vargen. Arsbok fran Varmlands Museum, Argang 84.
Andra upplagan, AB Ystads Centraltryckeri 74013, Sweden.
Fritts, S. H. 1982. Wolf depredation on livestock in Minnesota.
U.S. Fish and Wildlife Service Research Report 145, 11 pp.
Fritts, S. H., Paul, W. J., Mech, L. D., and Scott, D. P. 1992.
Trends and Management of Wolf-Livestock Conflicts in Minnesota.
U.S. Fish and Wildlife Service Resource Publ. 181, 27 pp.
Gustavson, C. R. 1982. An evaluation of taste aversion control of
wolf predation in northern Minnesota. Applied Anim. Ethol. 9:63-71.
Mech, L. D., Fritts, S. H., and Nelson, M. E. 1996. Wolf management
in the 21st century: from public input to sterilization. J. Wildl.
Res., 1:195-198.
Mech, L. D. , Harper, E. K., Meier, T. J., and Paul, W. J. 2000.
Assessing factors that may predispose Minnesota farms to wolf depredations
on cattle. Wildl. Soc. Bull. 28(3):623-629.
Paul, W. J. 1999. Wolf depredation on livestock in Minnesota annual
update of statistics-1997. U.S. Department of Agriculture. Grand
Rapids, MN
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