Bait-shyness

Rats are initially reluctant to take new bait. This bait shyness can be overcome by applying urine of estrous females to attract males, and male urine to attract females, unless pregnant. Males consume more of a feed if female urine odor is present (Gao, 1991). Bank voles are attracted to traps scented with 16-5a-androsten-Sa-ol (Baumler and Haag, 1989). 

A novel odor for attracting rats or mice to bait is carbon disulfide. It is found in the breath of rats, serves in communication about food, attracts rodents to bait, and increases bait consumption (Bean etal, 1988). Use of carbon disulfide and carbonyl sulfide in baits attracts mice and rats and prevents bait shyness from... 

Field results indicate that bromethalin bait was exceptionally effective against both Norway rats and house mouse populations. Bait acceptance was excellent with no signs of bait-shyness observed. 

The concentration of bromethalin in rodent baits is 0.005% or 0.01%. It is effective against rodents that are resistant to anticoagulant rodenticides and does not induce bait shyness. Anorexia and neurological effects occur after an effective dose has been consumed. 

An even more important derivative is 3-[3-(4 -bromobiphenyl-4-yl)-1,2,3,4-tetrahydronaphth-l-yl]-4-hydroxycoumarin (brodifacoum, 35). This anticoagulant of exceptional potency is capable of control resistant rodents as well as several noncommensal species. Contrary to first generation anticoagulants, a bait concentration of only SO mg/kg brodifacoum is adequate to give control even in a single feeding for most species. As with other anticoagulants, vitamin K, is an effective antidote. In contrast with other acute rodenticides, symptoms are delayed and no bait shyness is observed (Dubock and Kaukeinen, 1978). Its effectiveness... 

In the three examples presented, the conditioned aversion response played the leading role. In the first, It was recognized that the response is probably the most effective at manipulating the food habits of a wild carnivore. In the second, the problem associated with this response ("bait shyness") In getting adequate acceptance of a treated bait when using a reproductive Inhibitor led to Its use as a repellent. In the third, extensive screening efforts for a bird repellent Identified one material, methlocarb,... 

---