The effectiveness of frightening devices for reducing coyote predation on domestic sheep has not been adequately studied. Portable, battery-operated strobe light/siren devices protected pastured sheep from coyotes for a mean of 53 nights (10 trials) and 91 nights (5 trials). Results of ongoing tests of the devices for reducing predation on herded sheep on summer range in western Colorado have so far been encouraging. Future research needs are outlined.

Four individually penned coyotes (Canis latrans) that had learned to kill live domestic rabbits for food were presented with one black and one white rabbit during daily 1-hour sessions and punished by a brief, severe shock from a high-voltage collar each time they attacked the black rabbit. One coyote did not learn the color association; after three shocks, it refused to kill either rabbit for 10 days but killed both indiscriminately when retested 4 weeks later. The other three coyotes learned to avoid black rabbits after only three to five shocks and, when repeatedly retested without shock at several-week intervals, did not begin killing them again until 3 to 9 months later. These animals' rapid acquisition and long retention of an avoidance response to a certain class of prey suggests a potential for aversive stimuli to reduce coyote attacks on livestock.

A field study of unpadded and padded foothold coyote traps was undertaken in six western states in 1986-1987. Tests were designed to determine the capture efficiency and extent of foot injury caused by different trap modifications. Results were similar to an earlier study undertaken in 1984-85 that showed padded traps reduced foot injury but captured and held fewer animals than did unpadded traps. Both studies showed that unpadded long-spring traps used operationally by Federal Animal Damage Control specialists were the most effective (75-78% capture rate) but caused more foot injury. Padded long-spring traps were intermediate in efficacy (52-57%) and foot injury, while padded "Soft Catch''™ traps were the least effective (30-58%) but caused the least injury to captured coyotes.

A portable 12-v battery-operated coyote frightening device was developed for reducing coyote predation on sheep and evaluated on fenced pasture farm flock operations (1979-1982). In 1986, the final experimental model consisted of a PVC case, a timer, a blinking strobe light, and a warbling type siren that was activated for 7-10 seconds at about 6-7 minute intervals throughout the night. The devices were generally suspended about 2 m above the ground and were activated at dusk by a photocell and turned off about 2 hours after dawn by a timer. Here we report tests on high mountain summer sheep ranges (1982-1987), evaluation of the devices by ADC and external cooperators (1987-1990), and efforts to make the devices commercially available. On high mountain summer range, the devices reduced sheep losses on average about 60% with a mean dollar value savings of lambs of over $2,400 per sheep band. In the operational evaluations, 84% of our cooperators indicated that coyote predation on lambs was lowered when devices were used. Manufacture and sale of the device under the name ''Electronic Guard" was begun in 1991 by the ADC Program's Pocatello Supply Depot.