Coyote Predation on Sheep, and Control by Aversive Conditioning in Saskatchewan

Abstract

A study was conducted in 1975 and 1976 to assess domestic sheep (Ovis aries) losses to coyotes (Canis latrans) and evaluate the effectiveness of lithium chloride (LiCl) for controlling depredation in Saskatchewan. Nineteen seventy-five was a control year during which no program of aversive conditioning was in place. In 1976, lithium chloride was introduced as a taste aversion producing agent in treated baits and carcasses at 16 sites. Results were collected through personal interviews with cooperators and by means of mail-in questionnaires. Total lamb and sheep mortality attributed to coyotes within the monitored flocks was 4.0% in 1975 and 1.5% in 1976. Coyotes preyed on lambs 90% of the time in 1975 and 78% in 1976. In 1975 coyotes killed 802 lambs and 80 adult sheep in the monitored flocks. Within the total flock population, lamb losses were 3.6% and adult sheep losses were 0.4%. In 1976 coyotes killed 223 lambs, (2.3% of lambs) and sheep losses remained relatively stable at 78 (0.7% of adults). Lamb losses comprised 1.1% of the total flock population, and adult sheep losses 0.4%. During a period of relatively stable pricing, monetary losses were estimated at $41,195.34 in 1975 and $11,531.00 in 1976. The concurrence of lethal and other nonlethal coyote control measures, together with absence of coyote demographic data, precludes the unequivocal statement that the 66% reduction in predation was caused by LiCl treatment, but we suggest that LiCl was a major influence.