Información existente de la investigación

Although natural prey comprise most of their diet, wolves will kill and eat domestic livestock. The domestic prey of wolves includes cattle, sheep, turkeys, horses, geese, goats, chickens, ducks, and pigs. Most depredations occur in summer when livestock are released to graze in open and wooded pastures. Husbandry practices such as calving in forested or brushy pastures and disposal of livestock carcasses in or near pastures contribute to increased incidences of depredation.

To minimize economic loss to ranchers in Minnesota, a program is in place that compensates livestock owners for depredation losses. To initiate the claim process, the producer reports a livestock kill to a conservation officer or county extension agent. The conservation officer is charged with verifying the loss as wolf-caused. This is often done with the assistance of US Department of Agriculture (USDA), Wildlife Services Program. The county extension officer determines the value of the livestock and the Minnesota Department of Agriculture processes the payment. The number of complaints and verifications, as well as funds paid in compensation, has been recorded since the program's inception. The total compensation paid in Minnesota since 1977 has ranged from $14,444 to $42,739 annually.

As the wolf population and range expands, so do the number of livestock depredations (from 29 complaints and 15 verifications in 1979 to 201 complaints and 113 verifications in 1998). Although a small fraction of the farms (1% of 8,000 farms) within wolf range are affected by depredation, for some producers the monetary loss is substantial. The recent increase in livestock depredations caused alarm among livestock growers in Minnesota.32 Some go as far as implicating the increasing wolf population as the primary cause of the loss of many small family-farms in Minnesota. 32 S.R. Kellert, 'The public and the timber wolf in Minnesota. A Report of the International Wolf Center' (Ely, Minnesota, 1999).

Many livestock producers argue that the compensation program is not adequate. First, they assert that the actual number of depredations is much higher than the statistics show. The president of the Minnesota Cattleman's Association believes that more than 90% of the depredations go unreported because of missing carcasses. At present, farmers are reimbursed up to $750, minus the amount received from insurance, for lost livestock. According to a University of Minnesota study, $750 is adequate to fully compensate for loss of sheep and turkeys, but loss of cattle is only partially compensated. Some believe that 100% compensation as implemented in Wisconsin is warranted. (Wisconsin ranchers are required to implement various preventive measures before compensation is paid).

The second assertion is that, even if a carcass is available, the verification process is too exacting, as demonstrated by the few verifications relative to the number of complaints. Currently, verification requires a wounded animal or the remains of a dead animal (or, if a carcass is missing, evidence of a kill such as blood and rumen) and evidence of wolf involvement. According to the USDA's Wildlife Services program, the cause of the discrepancy between the number of complaints reported and the number of verified incidences is twofold. In addition to wolf depredation, other species (such as coyote, black bear and domestic dogs) prey on livestock. William Paul the District Supervisor for USDA's Wildlife Services,33 estimates that at least 20 to 25% of the complaints reported to Wildlife Services are coyote kills. As a result, the severity of the wolf depredation problem issue is often exaggerated. Also, wolves scavenge, and thus ranchers sometimes mistake natural mortality or non-wolf kills as wolf-caused. Of the depredation complaints received in 1998, 58% were verified as wolf kills. While acknowledging that the actual number of depredations is higher than what is verified, Wildlife Services believes that wolf depredation is problematic for less than 5% of Minnesota farms in wolf range.

In addition to the compensation mentioned above, farmers also receive assistance from Wildlife Services to remove 33 personal communication, 1998.

depredating animals. The primary method of control is trapping and removal of problem wolves. Since 1979, the number of wolves trapped has ranged from 15 to 227 annually, and the number of wolves lethally removed has ranged from 6 to 216 annually - up to 10% of the wolf population but far fewer than the farmers believe is necessary. Paul agrees that currently the Wildlife Services program is not adequately addressing wolf depredations in Minnesota but maintains that Wildlife Services could at least keep pace with the increasing trends if the program had more resources.

Some argue that livestock growers need to take some responsibility, such as exploring non-lethal methods for deterring depredation.34 There are numerous techniques proven effective under various scenarios, particularly when used in combination.35 However, Paul asserts that many of these techniques have been tried with limited success in Minnesota. For example, net wire and electric fences with anti-predator designs can be effective in smaller areas near the bam but in larger, forested pastures, the costs of acquiring and maintaining such structures are prohibitive. Similarly, flashing lights and sirens are most useful for reducing depredation in small pastures, but without a physical deterrent, their effectiveness wanes even in small areas. Lastly, guard dogs have been used for centuries in Europe and Asia and have proven successful in the western US. In addition to requiring time to bond with the livestock - and thus not providing an immediate solution - their effectiveness in Minnesota is questioned because of the difficulties in protecting livestock in forested pastures. Despite these shortcomings, Paul believes that guard dogs are the most viable option, especially for deterring coyote depredation.

Others have suggested using a trapping and firearms season as a potential control method. Although shooting alone is unlikely to be effective, hunting - in combination with 31 Kellert, 'The public and the timber wolf in Minnesota'.

35 D.H.Cluff & D.L. Murray, 'History of Wolf Control' in L.N. Carbyn, S.H. Fritts & D.R. Seip (eds), Ecology and Conservation of Wolves in a

Changing World (Canadian Circumpolar Institute, Edmonton, 1995),

trapping - could be a viable option. The success of trapping in controlling wolves is well documented but so too is the public's antipathy towards trapping. Anti-trapping campaigns in the 1930s and again in the 1970s were successful in effecting leg-hold trap restrictions in several states. Despite technological advancements in trap design (such as offset jaws, padded jaws, and tranquillizing tabs), public acceptance of trapping remains low. In two distinct studies of attitudes and behaviors toward the gray wolf in Minnesota, a substantial proportion of respondents stated they were ethically opposed to harvesting wolves for their fur or for sport.36 (Currently, toothed jaws are prohibited in the US but are used for research and removal of depredating wolves). Most feared a legal harvest would result in excessive and unsustainable mortality.