Microencapsulated Lithium Chloride Bait Aversion Did Not Stop Coyote Predation on Sheep

Experiments were conducted with microencapsulated lithium chloride to find a concentration that would produce optimum sheep-bait aversion and to test the transfer of the bait aversion to sheep-killing aversion in naive (no sheep-killing experience) and sheep-killing coyotes (Canis latrans). Lithium chloride at 1.08 g/500 g of sheep flesh, fed to coyotes at a rate of 500 g of treated flesh/10 kg of coyote body weight, produced the strongest bait aversion of the 4 concentrations tested. However, after showing strong aversion to baits fed at the above concentration, most coyotes (both naive and experienced) killed and fed on lambs, showing no transfer from bait aversion to predation aversion. J. WILDL. MANAGE. 47(4):1010-1017 Conditioned taste aversion has been promoted as a method to prevent coyotes from killing sheep. The method entails treating mutton baits with a strong emetic, lithium chloride (LiC1), and placing the baits on sheep range. Presumably, coyotes find and eat the baits, become ill, and subsequently avoid sheep because they have learned to associate mutton flavor and sheep with sickness. The application of LiCl-conditioned taste aversion to reduce coyote predation on sheep originated with Gustavson et al. (1974). Subsequently, Gustavson et al. (1976, 1982), Ellins et al. (1977), and Ellins and Catalano (1980) reported that LiCl baiting appeared to be effective. However, other investigators obtained negative results. Griffiths et al. (1978) reviewed prior work on the subject and concluded that no valid judgment could be made about the effectiveness of LiCl for controlling coyote predation on sheep. Recent field studies and experiments (Burns 1980, Burns and Connolly 1980, Bourne and Dorrance 1982) indicated that conditioning with LiCl baits did not stop coyotes from killing prey. Bourne and Dorrance (1982) reported that LiCl baits, and probably bait aversion, did not measurably reduce coyote predation of lambs on farms with LiCl baits compared to farms with placebo baits (no LiC1). Burns (1980) demonstrated that, with high LiCl doses, the salt flavor of LiCl interfered with the ability of coyotes to form aversi ns to baits and prey killing, a finding supported by Conover (1982). Later, Burns and Connolly (1980) produced a blacktailed jack rabbit (Lepus californicus) bait aversion with a lower dose of LiCl that reduced salt-taste interference. After showing bait aversion, however, coyotes continued to kill and eat jack rabbits. Coyotes easily discriminated between baits and live prey and after killing, fed, probably because they detected no LiCl flavor and odor Ellins and Martin (1981) reported that coyotes could use LiCl odor to discriminate between treated and untreated