"bitter chemicals are more likely to be effective repellents for use against carnivores and omnivores rather than herbivores (Beauchamp 1997)."(251)

"When capsaicin is consumed, it stimulates the trigeminal nerve, causing irritation in mammals but apparently not bothering birds due to neurological differences between these two groups of animals (Mason and Maurinak 1983). As a result, capsaicin can be used to repel mammals but not birds. Such a repellent could be used, for instance, to keep squirrels (or bears) from eating birdseed from feeders (Fitzgerald et al. 1997)."(252)

"When nausea follows the consumption of many items, animals develop an aversion to the food that had an unusual taste or odor. When animals become ill after eating a mix of familiar and novel food, they develop an aversion to the novel food (Kalat 1974)."(252)

"An animal’s experience in early life can have a dramatic and long-lasting effect on its food preferences."(253)

"Many species use chemicals (pheromones) to mark their territories. These chemicals may serve as area repellents if animals, especially juveniles and subadults, avoid treated areas because they think they are entering an adults defended territory (Lindgren et al. 1997)."(254)

"Gustavson et al. (1974) tried to use DBFA (deception based food aversion) to teach coyotes not to kill sheep. They hypothesized that, by distributing sheep carcasses and bait packages laced with lithium chloride, coyotes would consume them, become ill, develop an aversion to the taste of mutton, and stop killing sheep and lambs. While some initial tests yielded positive results (Gustavson et al. 1974, 1976; Ellins et al. 1977), other tests did not (Burns 1980, 1983a; Burns and Connolly 1980). Large-scale field tests involving replicated samples also produced mixed results (Bourne and Dorrance 1982; Gustavson et al. 1982; Jelinski et al. 1983; Conover and Kessler 1994)."(259)

"Attempts to use DBFA to teach coyotes not to kill sheep failed because chemically treated mimics are not similar to live sheep…. many coyotes developed an aversion to mutton baits but continued killing sheep."(260)

"Bears can destroy beehives, and it is easy to create a chemically treated beehive which mimics untreated beehives (Colvin 1975; Gilbert and Roy 1977; Polson 1983). It is also possible to mimic closely food handouts from humans (Figure 11.5; Cornell and Cornley 1979; Conover 1999) or nests, and attempts to use DBFA to address these problems have been more successful."(260)

"consumption of lithium chloride is rarely fatal and its effects last only for a few hours; not surprisingly, most attempts to avert predators from consuming eggs using this chemical have failed."(261)

"Unfortunately, the cost to register a repellent is so prohibitive that chemical companies are not willing to spend the necessary funds because the market for vertebrate repellents is relatively small compared to the use of insecticides on major crops."(263)