Non-lethal Alternatives for Predation Management

The ethical milieu in which wildlife biologists and livestock producers work continues to change as the concepts of environmentalism and animal rights and welfare have become introduced and normalized (Singer, 1975). The American public, including livestock producers, are mired within a typically human psychological quagmire of having a high demand for benefit, but a low tolerance for cost — that is, economic forces. Americans tend to demand a cheap, reliable food supply, while simultaneously demanding the existence of animals that, through predation activities, drive up production costs. Ironically, members of the urban public who may find fault with food and fiber production practices are also the customers on which livestock producers are dependent. In the United States, predation management has evolved from an attempt to eradicate or limit predator populations to the application of focused approaches for minimizing the damage done by predators. For coyotes, very large scale population suppression (using 1080), was restricted and sometimes apparently ineffective (Wagner, 1988). Other authors could find little correlation between the number of coyotes removed and the number of sheep kills at a California ranch (Conner et al., 1998). Further studies suggested that at least in some areas, dominant territorial coyotes are responsible for most sheep predation but typical lethal control methods tend to bias capture toward coyotes that are less likely to be livestock killers, thus, typical lethal methods such as trapping, snaring, and using M-44s are sometimes inefficient for solving depredation problems (Sacks et al. 1999, Blejwas et al. 2002). Lethal control methods are also often at odds with conservation needs (Shivik et al., 2003; Haber, 1996) and the general public favors the use of nonlethal methods of predation management in many situations (Reiter et al., 1999). Non-lethal methods provide a means of keeping predators established, while protecting livestock from predation and thus, a great amount of effort has been spent identifying and evaluating non-lethal predation-management options (Linnell et al., 1996). Effects of territoriality may improve efficiency of non-lethal methods relative to lethal control. Because predators, such as coyotes and wolves, are territorial and relatively long-lived, multi-year effects of management actions are possible, in contrast to lethal control which tends to be required annually (Bromely and Gese, 2001a,b). One goal of nonlethal methods with territorial species is to develop a bioexclusive effect such that resident predators do not kill livestock themselves, but further prevent losses by excluding other predators from the area. The field and body of knowledge on non-lethal techniques is growing, and a need exists to categorize and understand the plethora of methods that are being advertised by both scientists and charlatans. The objective of this paper is to provide a descriptive outline of nonlethal methods for predation management and to identify hindrances to their use and future development. I have performed a basic search of non-lethal methods that are available. These methods have been categorized and then discussed. Note that inclusion of a method in this paper is not an endorsement or guarantee of effectiveness of the technique; the effective application of any management method will depend upon the particulars of the management situation. Many methods that are applicable in small pasture situations, for instance, may have little or no applicability in large, open-range situations