Appetite, 1985, 6, 272-275

Coyote Control and Taste Aversion:A Predation Problem or a People Problem?

STUART R. ELLINSDepartment of Psychology, California State University, San Bernardino

Failures to suppress coyote predation on domestic livestock using the conditionedtaste aversion paradigm may be due to such factors as poor livestock managementprocedures and overestimated coyote predation data, in addition to theoretical andmethodological problems as indicated by Forthman Quick, Gustavson andRusiniak.

In their review of research on the application of taste aversion conditioning tocoyote management, Forthman Quick, Gustavson and Rusiniak (1985) explicatetheoretical and methodological factors that have contributed to a controversyregarding the effectiveness of this procedure in suppressing coyote predation ondomestic livestock. They have also alluded to the contribution of social factors to thiscontroversy. However, the experiences of the investigators involved in the AntelopeValley taste aversion project (Ellins & Catalano, 1980; Ellins, Catalano & Schechinger,1977) and of this investigator with many concerned parties since the termination of theproject suggest that a stronger case should be made. In other words, is this a problem ofambiguity in the effectiveness of the application of scientifically derived principles ofbehavior, or is it primarily a people problem?

It was evident at the outset of the Antelope Valley project that predatormanagement is an emotion-laden issue, the extreme camps consisting of the livestockgrowers who view predators as vermin that are a constant threat to their economicwell-being and conservationists who advocate the protection of all animals at any cost.In an attempt to provide equitable solutions to predator problems, scientists andadministrators ofgovernment-sponsored management programs often find themselvesin a crossfire between these groups. With this in mind, prior to initiating the project, aneffort was made by a band of enthusiastic but otherwise naive researchers to meet withfarmers, trappers, county administrators, local citizens, etc. to explain the project andpromote their interest and support. Cooperation was also solicited in obtaining baitfrom the livestock growers and in involving them in the determination of proceduresand locations for laying bait and collecting data. In general, although expressing somereservations as to the ultimate effectiveness of the procedure, most parties werecooperative and encouraging. Some livestock growers, however, did not believe thattaste aversion conditioning was worth trying and totally rejected the notion.

Once lithium chloride baiting began, the difficulties inherent in conducting thisresearch became clear. Data collection depended upon the herders' reports which oftenproved to be inaccurate. Herders, many of whom live in deplorable conditions, were

Address correspondence to: Stuart R. EItins, Department of Psychology, California State University, SanBernardino, CA 92407, U.S.A.

0195-6663/85/030272 + 04 $03·00/0 © 1985 Academic Press Inc. (London) Limited

COMMENTARY 273

often intoxicated and frequently did not know the size of their herds or the location oftheir sheep. Many sheep that were allegedly missing and presumed killed by coyotesremained unaccounted for. Some that were found were obviously killed by predatorsother than coyotes. These carcasses did not meet our criteria for coyote kills and werenot included in these data (see EIIins et al., 1977; Davenport, Browns, Workman &Nielsen, 1973). It was readily apparent that our data, which reflected only documentedcoyote kills, would be inconsistent with the claims of predation by the sheep growers.

Natural sheep and lamb deaths occurred continuously in the Antelope Valley as aresult ofdisease, injuries, birth complications, inadequate mothering, etc. The carcassesofmany of these animals either remained where they had fallen or were taken to "boneyards" adjacent to the grazing fields where they were left to decay, in either case settinga veritable table for roaming coyotes and ensuring that they acquire a taste for mutton.This practice is likely to result in increased predation. According to our calculations, inthe first year the herds under study lost approximately 4'5% of their stock to causesother than coyote predation, which is probably a conservative estimate based on ourobservations alone. In the second year, actual data on deaths due to other causes werenot collected; however, the number appeared to be substantial. Deaths due to otherpredators in the first year comprised 0'16% of their stock and 0'24% in the second year.Most of these deaths were attributable to dogs. There are two types of dogs in thevalley: domestic dogs belonging to neighboring farms and homes and feral dogs thatare often seen in packs. Both types are known to kill sheep, but only feral dogseat baits their prey; the domestic dogs typically go home to eat. Thus, some ofthese kills cannot be prevented because LiCl treatment offers no protection againstthose domestic dogs that do not eat the LiCI bait. The sheep herds in this project lostapproximately 1'3% of their stock to coyote predation in the first year and 0'5% in thesecond year. These losses appear to be within tolerable limits when one considers thenumber of losses due to other causes.

At the termination of the research phase of this project, the sheep growers wereasked to continue LiCI baiting themselves. They were provided with instructionswritten in English and Spanish concerning the placement of bait and the acquisitionand preparation of the LiCI solution to be injected into the carcass. Free injectionequipment was provided at this time and demonstrations of its use given. Packets ofLiCI were prepared and made available to the sheep growers at no cost by the LosAngeles County Department of Agriculture. The LiCI contained red dye which enabledus to determine the extent to which the herders were using the LiCI provided. It wassubsequently found that very few baits were laid by the herders; in most cases the sheepgrowers never used the equipment that they were given and never acquired LiClpackets at the agricultural stations. The reluctance of these people to continue baitingwas expressed in several ways. One sheep grower indicated that he felt that as ataxpayer it was the responsibility of the government to protect his herd. Another opinionwas expressed that, in spite of the encouraging results of our taste aversion conditioningexperiment, killing coyotes is the only effective way to solve the predation problem. Inthe Antelope Valley it is a common practice to shoot a coyote and hang its carcass on afence post while proclaiming that "this is one coyote that will never kill again". Ingeneral, it seemed that the sheep owners simply were not concerned enough aboutcoyote predation to take the minimal efforts to bait. In fact, one might wonder whetherthere is a predation problem at all.

There is no question that, given the opportunity, some coyotes will kill sheep andother livestock, and often do. Unattended lambs make especially easy prey and tasty

274 S. R. ELLINS

meals. In addition, there are many livestock growers who are responsible businessmen,who keep current and accurate records of the status of their herds, and who expresslegitimate concerns regarding problems of predation and the welfare of their stock. Atleast one such livestock grower participated in the Antelope Valley project. However, itis the contention of this investigator that problems of coyote management andpredation are mostly exaggerated by individuals who live and work in agriculturalsettings and continue to manifest a 19th century wild west mentality of "man againstnature". It is this prevailing anachronistic attitude, not the alleged devastation oflivestock herds that is commonly reported, that is responsible for the irrationalindictment of an entire species for acts probably committed by a few and facilitated byirresponsible management procedures by the very individuals who are making thecomplaints. In addition to being predators, coyotes are opportunistic scavengers thatwill eat anything that is chewable (Gier, 1975). In fact, there is ample data suggestingthat under most favorable foraging conditions coyotes prefer preying on small rodentsrather than on large mammals, the killing of which requires a considerable investmentin time and energy and represents some danger (Bekoff & Wells, 1980). If concernedlivestock growers would stop inviting predation by keeping better track of their stock,by properly disposing of carcasses, and by entreating their neighbors to keep their dogshome, etc., kills would undoubtedly be reduced. Given the availability of alternativefood, many potentially offending predators are likely to seek something else to eat.

Taste aversion conditioning is a robust and well-documented behavioralphenomenon (Riley & Baril, 1976) that superficially appears to be simple in itsapplication. However, conditioning effects in laboratory experiments have been foundto be highly sensitive to methodological variation (Best, Best & Henggeler, 1977). It istherefore not surprising that many investigators who are not familiar with the relevantscientific literature in the psychology of learning and conditioning, and who do nothave experience in producing taste aversion effects in laboratory animals, wouldachieve negative findings when applying taste aversion conditioning to coyotepredation. This is especially true of those investigators who hold the typical attitudes ofthe agricultural community, the bias of which is to maintain costly predator controlprocedures that have historically been ineffective while rejecting inexpensive proce­dures that do not produce dead coyotes. It is clear that livestock losses due to predationand other causes can be reduced significantly if proper livestock managementprocedures are employed and coyotes are appreciated as a beneficial component in thebalance of nature.

REFERENCES

Bekoff, M. & Wells, M. C. The social ecology of coyotes. Scientific American, 1980 (April)130-148.

Best, P. 1., Best, M. R. & Henggeler, S. The contribution of environmental noningestive cues inconditioning with aversive internal consequences, In L. M. Barker, M. R. Best & M. Domjan(Eds.), Learning mechanisms infood selection. Waco, Texas: Baylor University Press, 1977.

Davenport,1. W., Browns, J. E., Workman, 1. P. & Nielson, D. B. Assessment of sheep losses. InF. H. Wagner (Principal Investigator) "Predator control study", Final report, Four CornersRegional Commission, Utah State University, Logan, Utah, 1973.

Ellins, S. R. & Catalano, S. M. Field application of the conditioned taste aversion paradigm tothe control of coyote predation on sheep and turkeys. Behavioral and Neural Biology, 1980,29, 532-536.

Ellins, S. R., Catalano, S. M. & Schechinger, S. A. Conditioned taste aversion: A field applicationto coyote predation on sheep. Behavioral Biology, 1977, 28, 91-95.

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Forthman Quick, D. L., Gustavson, C. R. & Rusiniak, K. M. Coyote control and taste aversion.Appetite, 1985, 6, 253-264.

Gier, H. T. Ecology and behavior of the coyote (Canis latrans). In M. W. Fox (Ed.). The wildcanids: Their systematics, behavioral ecology and evolution. New York: Van NostrandReinhold, 1975.

Riley, A. L. & Baril, L. L. Conditioned taste aversion: A bibliography. Animal Learning Behavior,1976, 4, 15-135.

Received 26 November 1984