p. 12

Our assessment of the research indicates that coyotes acquired bait aversions but generally did not develop an aversion to live prey after feeding on sickness-producing baits and carcasses. Various applications of aversive chemicals to the necks or bodies of sheep have been unsuccessful in establishing aversions to live prey in coyotes (Burns 1983b, Burns and Mason 1996).

p. 13

We provided coyotes water ad libitum and fed the 1 unskinned front or hind quarter of a lamb/day for 4 days after killing the lamb in the pretrial to enhance experience with sheep as a food source.

p. 14

We continued testing each coyote for a 1-hour period on each of 2 consecutive days during weeks 2, 4, 7, 11, 16, and 22 to determine the duration of the aversive conditioning. We attempted to avert all attacks on the lamb during the all trials by delivering a 1- to 3-second continuous or briefly interrupted shock to the coyote each time it actively pursued and was within 5 m (usually within 2 m) of the lamb or when the coyote closely approached the lamb from the rear and attempted to bite it.

Four of 5 coyotes attempted 7 attacks on individual lambs during the first trial on 13 or 14 May (Table 1). The 4 coyotes initially pursued lambs an average of 3.4 minutes (range=0.2-6.2 min) after being introduced into the test area.

p. 15

Coyote 5366 pursued the lamb, was averted with a shock, slowly approached the front of the lamb 21 minutes later, and again was averted by a shock. Coyote 5037 pursued the lamb, was averted with a shock, immediately pursued the lamb, and again was averted. This coyote pursued the lamb 2 and 86 minutes later and each time was averted.

We retested the 5 coyotes on 14 or 15 May, 1 day after the first trial (Table 1). Two coyotes (5162, 5037) did not pursue lambs. The coyote (5348) that did not attempt to attack a lamb on the previous day actively pursued a lamb 9.8 minutes after the trial began and was averted with a shock. Coyote 5157 slowly approached a lamb from the rear and nipped at the lamb’s flank. Coyote 5366 slowly approached a lamb from the rear and suddenly seized it by the hock before we were aware that it was going to attack. We averted both attempted attacks by an electric shock, and neither lamb was injured by the coyotes…. Only 3 attempted attacks by 3 different coyotes occurred during the remainder of the study, and each was averted by a shock from the training collar.

The last attempted attack by each coyote occurred an average of >4 months before the end of the study (Table 1).

During subsequent trials, coyotes slowly approached lambs and attempted to bite or nip the flank area on 3 occasions, quickly circled a lamb and attempted to bite the flank on one occasion, and ran at a stationary lamb on another occasion.

Before being shocked, coyotes did not tend to avoid lambs, but after being shocked, they often avoided lambs and retreated when a lamb approached; during 2 retreats, coyotes 5348 and 5037 displayed submissive behaviors.

Coyotes appeared to quickly associate the shocks from the electronic collar with their attempted attacks on lambs. Our training sequence with the collar stopped all attempted attacks, and altered coyote behavior towards lambs by decreasing the probability of an attempted attack, eliminating consecutive chases, causing switches from active pursuits to sneaking behind lambs and attempting to bite or nip the flank area, and causing avoidance of lambs.

We believe prey-killing aversion can be most readily established by applying response-contingent aversive stimuli during the chase and attack phase of the predatory sequence.

p. 16

Also, neck collars containing sublethal doses of sodium cyanide or capsicum oleoresin on sheep or lambs were not effective to control coyote predation because coyotes redirected attacks at the sides and rear of lambs after puncturing a collar.

Coyotes are territorial, such that a few individuals have relatively exclusive access to lambs and other prey in those territories. This suggests that research is needed to ascertain if only a few individuals need to be captured, collared, and aversively conditioned to protect lambs or endangered species such as black footed ferrets in those territories.