Wolves and Livestock
Along with natural prey such as elk, deer, and moose, wolves have also been known to kill cattle, sheep, and other livestock.Many people first point to the wolf when livestock losses occur. Let’s face it…blaming something makes us feel better, but this is more often another example of the wolf being targeted as a scapegoat and people not focusing on the right quandary. This will not solve any issues, for wolves, livestock, nor ranchers.
For decades, if not centuries, public and government have been killing wolves and other predators to protect livestock. For example, the U.S. government was practicing lethal control on coyotes for 80 years in an effort to increase sheep production, only to realize that this had no effect on the sheep industry! (2) The real culprits were increasing production costs and decreasing product prices.
In 2002, the BC Wild Predator Loss Control and Compensation Program was initiated, with compensation funds coming from the Ministry of Agriculture and lands. Under this program, ranchers are compensated for 75% of the value of an animal lost. In the Northwestern USA, compensation programs have been in effect for 20 years. These mitigation efforts are to minimize the chances of ranchers taking things into their own hands by shooting predators on their property that they view as a possible threat.
Look at the facts
-2008/2009: Throughout all of British Columbia there were only 70 verified livestock losses due to wolves.(1)
-2005 research done in Idaho, Montana, and Wyoming indicated that LESS THAN 3% of all livestock mortality was due to wolves, grizzly bears, and black bears COMBINED! (2)
Total livestock losses due to non-predators was at least 89%, with respiratory and digestive problems contributing the most (between 8 – 32%), (2).
This study points out that total cattle losses due to wolf depredation in Idaho, Montana, and Wyoming (AKA ranchland) are minor when compared to other causes of death, (2).
Misperceptions
Misperception #1: Wolves cost the livestock industry too much.
Fact: there are only a few losses each year which has minimal effects on the industry. However, to an individual rancher losing even a few animals seem like a lot. This leaves an angry impression which is often exaggerated and this is the voice that gets heard.
If your ranch is within the territory of a wolf pack and there are no problems, ranchers are advised to LEAVE THE PACK ALONE; they may be protecting livestock from wolves that are more prone to go after livestock (1).
Misperception #2: Wolves kill for fun and in excess of what they can consume, often referred to as "surplus killing" .
Fact: Surplus killing is considered uncommon in the wild, however a few documented cases do exists (3).
Wolves may not return to a carcass once it is disturbed by humans, leading to the thought that excessive killing is occurring when it would not have (1,2). This could also lead to wolves killing another animal to replace the food source they have just lost (1).
The number of wolves feeding on an animal may not be able to consume the entire amount (1). In the wild, any leftovers would provide for scavengers and contribute to biodiversity.
Surplus killing does occasionally exist among sheep in the Northwestern US, but has not been documented in cattle. (2)
Livestock and domestics display poor anti-predator behaviour, which are reactions recognized in nature to deter predator advances (2). Sheep especially have prey traits that make them more vulnerable to predators (2). It is important for wolf conservationists to acknowledge that some livestock depredation is caused by wolves each year, although minimal. Livestock production and wolf habitat often overlaps, and where they do, there will occasionally be losses. It is valuable to recognize both sides of the story, and by investigating concerns we can discover the facts.
Issues of safety are most often unwarranted. The real dangers are poison on a landscape, more guns and traps. The REAL issue is tolerance.
Work to recognize wolves an important part of an ecosystem, not something to be liked or disliked, to improve tolerance. Note that a deep-rooted social identity often influences an individuals’ tolerances more than actual encounters with wolves and other predators. Regulations or guidelines can also be viewed as threat to private property rights and gov’t interference. Perceived risk can be as important as actual experience in shaping attitudes….therefore EDUCATE!
USA working to be proactive with partnership between Defenders of Wildlife, US Fish and wildlife service, Nat’l wildlife Research Centre, Native American tribes, community conservation groups, Livestock Producers Advisory Group.
METHODS OF PREVENTION –this is KEY! Don’t let predators acquire the habit or taste. Want to prevent wolves from being ATTRACTED to livestock operation.
Change devices and methods frequently as wolves adapt.
Most rational and effective approach (from Mech anf Boitani's "Wolves; Behaviour, Ecology, and Conservation 2003)
1. Prevention by providing incentives to improve protection of livestock (fences, guard dogs, shepherds, etc.)
2. Compensation of farmers for damage
3. Elimination of individual wolves causing damage
References:
1. MacKay, Andy. (2005). " Mitigating Cattle Losses Caused by Wild Predators in British Columbia, A Field Guide for Ranchers". Agriculture and Agri-Food Canada, [
2. Muhly, T.B., Musiani, M., (2009). Livestock depredation by wolves and the ranching economy in the Northwestern U.S., Ecological Economics, doi: 10.1016/j.ecolecon.2009.04.008.
3. www.wolftrust.org.uk/a-d7-depredation-surplus.html
Below is a summary of various methods of prevention and information about their weaknesses and strengths:
· SURVEILANCE and MONITORING shepherds, herders, range riders
-Shepherds (work with guard dogs for easier and more coverage, get alerted and respond)
-Range riders (hired especially during grazing season; summer-fall)
-patrol at dawn and dusk when wolves most active
-boost effectiveness by using dogs to alert and cover more land area
-count stock regularly when possible especially rugged terrain where dead stock can go unnoticed
-monitor for health of stock, ensure deterrents set, monitor stock agitation as well as presence of wolves
-keep good records to identify patterns (problem areas, time of year, etc)
- Italy poor surveillance is biggest factor associated with losses
· CARCASS REMOVAL (OR OTHER EDIBLE REFUSE)
-haul away, burn, burn
-carcass removal by gov’t or group (rendering facility or commercial landfill?)
-carcass pit –locate away from stock
- at least 8 feet deep
- regularly burn or bury carcasses in pit
- surround pit with fencing provides more barrier
-wolves conditioned to livestock killing often kill on neighbouring farms (work together)
· LIVESTOCK GUARDIAN DOGS (LGD) shown to reduce predation by 11 – 100 % ; documented mostly for coyote (Smith et al 2000)
-used in Eurasia for centuries, one of oldest methods, some places thousands of years
-sometimes even mere presence deters wolves
-support with human presence - > aid in alerting shepherds; respond quickly and bring other deterents (not practiced this was as much in N.A…often left alone)
-quite effective as long as used by trained shepherds; no shepherd increased killing of guard dogs
-do not use near wolf den sites in spring (April through June) when wolves aggressively
defend pups from other canines (could actually increase chance of conflict)
-Factors affecting success:
1. Number of dogs per head
2. Inadequate training of dogs
3. Proximity of bedding ground to forest
4. Absence of shepherds
Breeds- Great Pyrenese, Anatolian Shepherd, Akbash, Mastiff, Wolfhound and others (but
not all registered have instincts needed, -percentage of LGD’s as successful
guardians varies 66 – 90 %)
-(guard dogs NOT herding dogs)
- initial cost $240 - $3000
-must socialize and bond from young age (6-8 week pups put in with stock, older that 8-10
weeks passed primary socialization stage (Smith et al 2000); (must bond with livestock
and not people)
-introduce to fences and working areas
- don’t let dogs chase down wolves, keep with the livestock to protect
- most effective when use 2 dogs (or a few, but NOT a pack size where distract eachother);
*2 dogs may be viewed as pack, especially by lone wolves (avoid encounters)
-prevention dual, disrupt normal predation sequence of wolves (avoid territories or
distracted into social behaviour such as greeting, play, etc) as well as direct aggression
- recommend establish LGD and livestock in possible conflict areas BEFORE wolves
arrive so LGD establish territory
- 1989 report 82% livestock producers using LGD in Canada and USA thought economic
asset
- donkeys and llamas also used as guardian animals with variable effectiveness, as well as
certain cattle breeds (require enclosed pasture to work best)
- N. America llamas can help protect sheep from individual coyotes or dogs but may fall
prey to grizzlies, cougars
· CALVING and BRANDING
-afterbirth can be strong attractant…plan time and location
-seasonal timing: delaying release of newborns onto spring pastures can sometimes decrease losses
-schedule and manage for condensed calving season to monitor better
-perform pregnancy test (often assume pregnant when not) to determine calving and numbers
-monitor more closely at this time
-some ranchers repost success by keeping some bulls as part of calving herd as well as donkeys and other aggressive animals to mingle (defend, teach, and toughen up)
-unknown whether cow-calf pairs less vulnerable unknown (different results, some ranchers in US that converted to cow-calf pairs experienced attacks for first time)
· FENCING AND FLADRY
-closely placed and well maintained fladry seems successful many cases (red or orange cloth flags hung at 18 inch intervals); must maintain ie. keep bright and new (place 2 m outside conventional fence to prevent cattle from damaging or eating flags)
-most useful for temporary prevention when kept in small pastures (calving, lambing, overnight holding, rotational grazing)
> inexpensive, easily moved, quickly installed over large area
> used alone is most effective as short term deterrent
-Turbofladry more effective (estimated by 3 or more times), combines electric fence with fladry, powered by solar
-only for small pastures
-nightime enclosures – small night corrals; stock gets used to over time and will head there come evening
> with portable fencing move often to avoid plant damage
-some USA producers successfully using electric night pens
FLADRY
· Model Musiani and Visalberghi 2001: plastic flags measuring 50 X 10 cm sewn at 50 cm intervals on 0.2 cm diameter nylon rope, suspended 50 cm above ground tied to rebar posts at 30 m intervals (cost of commercial Fladry approximately US $0.19/m)
· Gaps of > 1 m between flags (= removal/loss of just one flag) enough o allow wolf crossing in captivity
· “Presence of available prey outside the Fladry boundary is critical for enhancing its effectiveness. …if wild prey is scarce, Fladry may be ineffective when applied on large properties and/or on several contiguous pastures”
-from Gillian Sanders workshop, Revelstoke November 2010: wolves and cougars are jumpers so need higher fence than bears. Combine Fladry to slow down and get zap.
-use chargers for predators, NOT for livestock; “Super Energizer 4” 1900 volts, 50 mile range (cost $250) [if off-grid $450], want 15,000 volts or more
-use voltmeters designed for predators too (if starting new)
-plug-in has more kick than solar, unit must be grounded (want wet earth, eg. directly under roof dripline can increase voltage by few thousand)
-grounding plates $17 or rods (rebar) [plate better for rocky areas], ground clamp
-SET-UP: rebar posts and insulators, need atleast 4-6 strands wire…if charge not enough will go through (nose shock is best learning experience)
-posts 10-12 feet apart, bottom wire (or fence) 5-6 inches above ground (or ground-out)
-less charge if earth dry and gravelly, so keep moist (eg. sprinkle water)
-galvanized wire better barrier than synthetic (stronger but more $), outside of rebar (harder to dislodge)
-SET UP 2: stucco wire hung around rebar posts and wire top (roll 100 feet $80, ¼ mile tensile steel $25)….better for coyotes b/c less gaps
-need to maintain fence (no sagging/fraying, less likely to part hairs), and check volt meter regularly to ensure working (set up somewhere easy to check often)
-suggests IF problems, then can bait fence to teach
-suggested model SE-4 from Parmak for plug-n, Parmak Solar Magnum 12 for solar units
· SEAONALITY AND PATTERNS
-from Musiani et al 2005 seasonal patterns reflect livestock calving, grazing practices, and seasonal variation in wolf pack energy requirements
-identified 3 season pattern in Canada((AB)
Depredation rates AB Grazing Calving
May-Sept=high May-Oct=most AB most late summer
Oct – Jan = med sometimes -Dec/Jan to early spring
Feb – April = lowest Feb- April = least grazing
Indicates annual reoccurrence for depredation and wolf culling (not solving)
-understanding these patterns can help improve planning and management, potentially alleviate conflicts
-can predict risk and plan for increased prevention (and investment of resources)
-snow accumulation in winter can add disadvantage to healthy stock, picked up on by predators
1. wolf pups born April-May increase energy requirements
2. late summer high energy requirements of wolf packs due to nurturing larger pups and packs before pop’n reduced by fall and winter mortality
3. depredation peak in May in Minnesota corresponds with newborn calves (Harper et al 2008)
4. decrease depredation in June in Minnesota may be related to availabiltity of deer fawns born in June (Harper et al. 2008)
5. AB late winter-early spring cold temperatures and deep snow often lead to supplementary feeding and this when most calving occurs
-note that in BC an increase in incidents also occurs in Feb/March when alpha’s are breeding and may leave youngsters and sub-adults unsupervised (Drew Carmichael, personal communication).
· BIOPHYSICAL LANDSCAPE -(Musiani research in Alberta)
-can determine high risk areas and where prevention measures should be focused
-relative importance of each factor in order to predicting depredation from highest to lowest
1. Elk density
2. Distance to building
3. Distance to raod
4. Slope
5. Distance to cover
-model showed depredation more likely in areas with higher elk density,
closer to
buildings, further from roads, on flatter slopes, and closer to forest cover.
- ranches more likely to be depredated were those which practiced wolf
culling, had yearling cattle herds, and monitored livestock more frequently
in fall (vs. winter & spring)
- dense vegetation and vegetated waterways may promote predation
· TYPE AND AGE OF STOCK
-may be behavioural characteristics of yearlings that make them more vulnerable
-some breeds more aggressive in defending and stronger maternal bonds
-some ranchers include a few longhorn steers, especially with yearlings
- Corriente, Brahman, (can cross with Herefords to get blend aggression to predators, mothering skills, heartiness, beef value, reproductive success
-cattle used to rugged terrain fair better than those unfamiliar with landscape
-some promising research bonding sheep to cattle to decrease sheep predation, also better for grazing use of land, minimizes stress weaning sheep, controls spatial distribution of sheep without fencing
· RAG BOXES
-can be very effective, mostly as temporary deterrent
-activated by radio-collared wolves close and shoots sounds and lights out
-most effective for small pastures (60 acres or less), especially when lambing or calving
-works to deter wolves and alert range rider/herder
-limited use to radio-collared wolves
-powered by 12-volt car battery (recharge few weeks) or solar panel
· RELOCATION
-diversionary feeding Defenders reimbursed ranchers N. Rockies for hay to lure cattle away wolf den (limited as wolves habituate)
-funding for alternative pastures
-design livestock watering system that draws cattle away from denning pack and forest
-relocation usually last resort, can be temporary or permanent
Ø Relocation of wolves: high mortality rate
· OTHER
-volunteer program: volunteers (wolf conservationists and cattlemen) serve as “wolf guardians” to help track wolf pack movements, install Fladry and fencing, watch over livestock
-work and plan as team to share costs and efforts (written agreement of expectations of roles and responsibilities recommended)
-cracker shells limited as wolves habituate to them
-bean-bag shells and rubber bullets, paintballs (learn how to use properly or serious injuries can occur)
-taste aversion – not effective
-Northern half of Sweden compensation for reindeer began 1996 paid on basis of verified reproduction or confirmed presence of predators in community grazing areas; compensation paid to local community rather than individual owners THUS gov’t pays to support predators
- stock other than reindeer paid by case, but county also helps fund prevention
· COMPENSATION Compensation programs often criticized for doing too little and being too much work. Compensation does not change attitudes towards wolves, but removing such a program program is potentially worse because it can create more hostility versus perceptions of being supported by public. Note that payments can reduce incentives to change husbandry practices which would lower risks.
-compensation for costs associated with prevention measures
-Defenders of Wildlife (USA) all types stock including guard dogs
-full market value even if killed in Spring
-sometimes general limits to animal value but no cap for individual citizen
-Canadian Wolf Coalition believes compensation only if practicing good husbandry and prevention (like northern Sweden)
-vet costs refunded
-“conservation performance payments” are monetary or in-kind payments made to individual or groups of landowners that contribute to specific conservation goals; outcomes of this program still uncertain
-must determine between predation and scavenging
Ø Haemorrhaging and bruising will not occur on dead animal that has been scavenged
Ø Soft membrane covering sole of lamb hoof indicates not walk, chances high that stillborn
Ø Lungs of stillborn lamb dark purplish-red and will sink in water
Ø Milk in stomach evidence of live birth
· CULLING – corrective, not preventative (Musiani et al. 2005)
-not shown to reduce depredation, immediately nor long-term (Musiani et al 2005)
-no evidence to show works as long-term solution, as depredations occur in areas that have been practicing lethal control for decades
-short-term response to depredation but not decrease wolf-depredation at a regional scale nor over long-tern (Musiani et al. 2005), thus REOCCURING seasonal-annual pattern for wolf depredation and wolf control in Western N.A. = cyclic and not address issue
-neighbouring packs or dispersers recolonize area
-may help reduce severe cases where individual or pack offend repeatedly, may help rid genetic or behavioural traits conducive to depredation (Musiani et al 2005), but not change occurrence if husbandry and environmental conditions not changed.
-“CONTROL ACTIONS WERE NOT AIMED, OR EFFECTIVE, AT DECREASING DEPREDATION AT A REGIONAL SCALE OR IN THE LONG TERM” (Musiani et al 2005)
-no evidence over 20 years to indicate removal by trapping decreased rate of depredation next year at state or local levels in Minnesota for cattle and sheep (Harper et al 2008).
-researching correlation between trapping and depredations in following years for all periods, areas, livestock at individual scale and at combined level showed either more depredations next year or non-significant changes when wolves killed by trapping (Harper et al 2008)
-unsuccesful trapping reduced rate of recurrence more than successful trapping or no trapping, indicating that human presence may have been the best deterrent (Harper et al 2008) with possible exception of removing adult male (alpha male)
-Harper et al.( 2008) showed that “as more wolves were killed one year, the depredations increased the following year”
> may be more wolves present in these areas or maybe wolves avoiding traps had learned to prey on livestock, and become more dependent as pack mates removes
-suggest that daily visits simulating trapping activities (human presence, foreign scents and objects) may be more cost-effective that trapping and killing wolves, especially where ranches are far from control personell.
-need better monitoring at many levels and careful design of hunting seasons to achieve politically acceptable hunting that offers conservation to ecologicaly important large carnivores.
-REMOVAL OF PROBLEM WOLVES
-Minnesota research indicated total number of wolves removed did not appear to affect the re-depredation rate (Harper et al 2008)
-People, carnivores, property, and wild resources all influence depredation, and this complexity makes it extremely difficult and unlikely that targeted individuals will be selectively removed even by experts.
-> age-sex class of carnivores causing property damage usually differed
significantly from those of hunted animals (Treves 2009).
-Treves (2009) states that “even if the culprits are targeted selectively, property damage may increase if hunting disrupts carnivore social organization and promotes new individuals or new denser populations of different species of carnivores that, in turn, may have greater impacts on property” (See wolf behaviour below).
· FUNDRAISING –share costs (ENGO’s, agricultural sector, government)
-eg .Wisconsin: Fund created for individual voluntary contributions on tax returns
-sell special wolf licence plates
-eg. Defenders of Wildlife
Livestock General
· Most killed during summer grazing season
· Highest losses in untended remote pastures
· “Higher levels of depredations are associated with certain husbandry practices”
WOLF BEHAVIOUR AND POPULATION DYNAMICS
-rarely attack adult cattle and horses
-prey more on sheep, goats and calves, some areas yearlings
-can tell if healthy prey (livestock or wild) becomes disadvantaged eg. deep snow (therefore patrol)
-quick learners and overcome fear of certain devices when used repeatedly over long period
-most problems occur certain times (Feb-March breeding season, when alpha’s away from pack sometimes; April-May when pups born and energy requirements increased; June-July when teaching pups to hunt). NOTE in Alberta, most depredations are in August.
Observable symptom of pack disintegration (loss of social stability regardless of population size) appears to be increase in attack rates on livestock, as indicated in Australia when using poison baits on Dingos (Wallache et al 2009).
-similar results with coyotes when review long-term data to show that control programs did not significantly reduce depredations (Saskatchewan and USA)
Wolves – in the past, government actions, bounties and hunting policies may have LEAD to splintering of stable packs, increased births and more wolves in more places…an exploited population.
-
loss of pack stability has created other problems as well, such as hybridization of wild canines (grey wolves, Eastern wolves, coyotes, dogs, dingoes) which are threatening survival of species and creating other concerns because of behavioural differences (eg. coyotes more adaptable to human areas, potentially greater threat to livestock, pets and humans)
-By maintaining wild ungulate population wolves can help manage transferable disease to domestics (eg. Bovine tuberculosis) as well as maintain wild ungulate population (overgrazing competition with domestic animals).
British Columbia 
News release about funding for ranchers in BC to prevent livestock losses and protect predators:
http://www2.news.gov.bc.ca/news_releases_2009-2013/2009AL0007-000191.htm
For more information on the Ranching Task Force visit: www.ranchingtaskforce.gov.bc.ca BC Cattlemen’s Association Wild Predator Loss & Compensation Program www.cattlemen.bc.ca/wplccp.htm
BC losses: 2008/09 total compensation paid out = $ 33,440.00 on 98 verified losses due to: grizzly 2%, coyote 14%, black bear 12%, cougar 1%, wolf 71% of the number of animals lost (BC Cattlemans Assoc, personal communication). This equates to 70 losses caused by wolves for the entire year.
Ontario
Payments are made to Ontario’s farmers under 3 Wildlife Damage Programs administered by the Farm Finance Branch of the Ontario Ministry of Agriculture, Food & Rural Affairs (OMAFRA)
Visit www.ontariosheep.org/PREDATOR.html for perspectives, prevention and compensation programs in Ontario. Note that coyotes, wolves, and dogs are all grouped into one category for losses, and there are no stats indicating changes in livestock numbers or values over the years.
Also see: www.omafra.gov.on.ca/english/livestock/sheep/predator.html
www.e-laws.gov.on.ca/html/statutes/english/elaws_statutes_90l24_e.htm for Ontario’s Livestock, Poultry and Honeybee protection act.
GREAT RESOURCE!!!! 
This publication is part of Defenders' of Wildlife comprehensive program and is their guide to non-lethal tools and methods to reduce conflicts: www.defende
rs.org/resources/publications/programs_and_policy/wildlife_conservation/solutions/livestock_and_wolves.pdf
Best guide to prevent livestock losses through addressing the root causes. The above PDF provides methods and examples of various predator-friendly approaches to guarding livestock, and discusses the limitations as well as benefits of different methods. Co-existence can be achieved; by protecting livestock as well as wolves and other predators from unnecessary deaths.
More information and links at www.defenders.org/programs_and_policy/wildlife_conservation/solutions/coexisting_with_carnivores/on_your_ranch/index.php
In the U.S.A. to date, with the help of members and sponsors, Defenders of Wildlife has invested more than US$2 million to compensate ranchers and reduce predation of livestock by wild predators.
Defenders has also helped reduce tension between Canadian ranchers and wolves. www.defenders.org/programs_and_policy/wildlife_conservation/imperiled_species/wolves/wolf_recovery_efforts/canada_wolves/in_the_field.php
Information from Defenders of Wildlife providing fast facts about the real causes of livestock losses, and how they compare to wolf predation…putting things into perspective! www.defenders.org/programs_and_policy/wildlife_conservation/solutions/wolf_compensation_trust/index.php To learn about specific projects by Defenders’ involving livestock and wolves and the Proactive Carnivore Conservation Fund they have set up: www.defenders.org/programs_and_policy/wildlife_conservation/solutions
/carnivore_conservation_fund/index.php 
Predator-friendly Ranching Blog: http://predator-friendly-ranching.blogspot.com/
UNGULATE HUNTING REGULATIONS HAVE CHANGED. Numbers have been high and in an effort to reduce primary prey for wolves (for caribou recovery) seasons have been lengthened and cows allowed to be hunted. A drop in the wild ungulate population too quickly will result in increased livestock losses, as observed with cougars in BC in recent past).
REFERENCES:
Musiani,M., C. Mamo, L. Boitani, C. Callaghan, C. Cormack Gates, L. Mattei, E. Visalberghi, S. Breck, G. Volpi (2003) Wolf Depredation Trends and the Use of Fladry Barriers to Protect Livestock in Western North America, Conservation Biology, pp 1538-1547, Vol. 17 No 6 Dec. 2003
Musiani M., T Muhly, C. Cormack Gates, C. Callaghan, M. Smith, E. Tosoni (2005). Seasonality and reoccurrence of depredation and wolf control in western North America. Wildlife Society Bulletin 2005, 33 (3): 876-887.
Harper E., P. J. William, L.D. Mech, S. Weisberg (2008). Effectiveness of Lethal, Directed Wolf-Depredationb Control in Minnesota. The Journal of Wildlife Management 72 (3): 778-783.
Wallach A.D., E.G. Ritchie, J. Read, A.J. O’Neill (2009). More than Mere Numbers: The Impact of Lethal Control on the Social Stability of a Top-Order Predator. PloS ONE 4 (9): 1-7, e6861.
Adrian Treves. (2009). Hunting for large carnivore conservation. Journal of Applied Ecology 46, 1350-1356. DOI: 10.1111/j.1365-2664.2009.01729.x
Robichaud, C. and M.S. Boyce (2010) Spatial and Temporal Patterns of Wolf Harvest on Registered Traplines in Alberta, Canada. Journal of Wildlife Management 74 (4): 635-643. DOI: 10.2193/2009-260
Rutledge, L., B. Patterson, K. Mills, K. Loveless, D. Murray, B. White (2010). Protection from harvesting restores the natural social structure of eastern wolf packs. Biological Conservation 143: 332-339. DOI: 10.1016/j.biocon.2009.10.017
