"substances that cause sensory irritation or pain usually are most effective. This is because sensory pain leads to immediate withdrawal, independent of learning."(176)

Unfortunately, when irritant chemicals dissipate (e.g, by evaporation or photolysis), there is usually an immediate resumption of the unwanted behavior."(176)

"A disadvantage of fear-inducing chemicals is that animals readily habituate to their presence."(176)

"When the ingestion of novel tastes by mammals… is followed by sickness, a learned avoidance usually results…. Conditioned Avoidance (CA) can occur after a single aversive experience, particularly when the intensity of sickness is great and the taste, food, or flavor is new. "(177)

"While evidence suggests that CA can be used to successfully manage nuisance complaints, … no lithium chloride or estrogen based method has been registered by the U.S. Environmental Protection Agency."(177)

"Gustavson (pioneer of CA methods) acknowledged that coyotes often resumed killing sheep shortly after conditioning, and ‘… once a coyote becomes a sheep-killer, perhaps it will be necessary to remove it from the population.’… the generalization of learning from consumption to killing is weak."(177)

"combinations of battery-operated strobe lights, sirens, and high frequency horns, placed on the edges of sheep pastures or bedgrounds and activated for short irregular intervals during the night and early morning, stopped predation for 27 to 136 nights."(177)

"coyotes fitted with collars that provided a contingent electric shock stopped attacks on rabbits for several months."(178)

Coyotes fitted with dog training collars that deliver, upon manual activation, "a mild static electrical discharge… after one to three training bouts, coyotes avoided or retreated from sheep in tests four months after initial sessions."(178)

"fences placed to exclude a predatory species may interrupt movement patterns or block migration routes of another."(178)

A Combination of multiple stimuli (e.g. fear inducing, irritants, and sickness inducing) is deemed more effective than any one method employed singly.(179)

"Development and implementation of ecologically sound and effective repellents is dependent upon a knowledge of the sensory Umwelt of the species in question."(179)