Jan 30, 2012 – Used To Like It, Now I Don’t
QUESTION:
In the past it seemed as though there was one rodent bait that stood above the rest. Now it is avoided despite any other food source around. Do mice build up a dislike for or a taste avoidance to these baits?
ANSWER:
Hopefully those things I have learned in the past are not now all outdated and incorrect, and one concept that was taught to us is that rodents can develop bait "shyness". There can be other factors involved instead, and we'll mention those too, but bait shyness could be possible where a rodent associates some negative feeling or reaction with the food (the bait) it has been eating, and begins to avoid that bait in the future. Or, perhaps even might avoid eating baits placed in stations if it somehow associates the station with the problem. This could be a rodent that has eaten less than a lethal dose of the bait but begins to feel ill, and decides that the bait and the ill feeling are connected. Mice, in particular, are nibblers and may not quickly consume enough of the bait to kill them.
View past Ask Mr. Pest Control questions.
In the past it seemed as though there was one rodent bait that stood above the rest. Now it is avoided despite any other food source around. Do mice build up a dislike for or a taste avoidance to these baits?
ANSWER:
Hopefully those things I have learned in the past are not now all outdated and incorrect, and one concept that was taught to us is that rodents can develop bait "shyness". There can be other factors involved instead, and we'll mention those too, but bait shyness could be possible where a rodent associates some negative feeling or reaction with the food (the bait) it has been eating, and begins to avoid that bait in the future. Or, perhaps even might avoid eating baits placed in stations if it somehow associates the station with the problem. This could be a rodent that has eaten less than a lethal dose of the bait but begins to feel ill, and decides that the bait and the ill feeling are connected. Mice, in particular, are nibblers and may not quickly consume enough of the bait to kill them.
Possible ways to overcome this are to make some changes in the baiting protocol. Use a different bait entirely, such as place packs instead of paraffin blocks, pellets instead of blocks, a non-anticoagulant instead of an anticoagulant, a different manufacturer's product just to change the food ingredients and the look or taste or feel of the bait. Put the bait stations in different locations. It's also worthwhile to make another inspection to be certain no alternative foods are available. After all, if the mice or rats are still present they must be eating something, and for rats finding water as well. If you are baiting on the exterior then there really could be plenty of alternative foods in neighboring properties. If you are baiting on the interior hopefully you are taking measures to rodent-proof the structure so that you can eventually deal with these rodents only on the outside. Continuous baiting on the interior leads to those problems we already recognize - dead rodents, flies, odors, etc. Of course, if this is some large commercial structure such as a warehouse the exclusion becomes a lot more difficult.
Dr. Corrigan, in his Rodent Control book, lists some possible reasons for poor bait acceptance, and I will just quote these:
- the choice of bait is just not attractive anymore (change baits)
- bait stations are no longer placed in high rodent activity areas, or where too much human activity is occurring.
- other food resources are available and more attractive.
- the bait has become unpalatable - rancid, moldy, bug infested, or contaminated with other unsavory odors and tastes from contamination.
So, sure, it is possible for various reasons that these rodents no longer want to eat the bait, and making changes in the bait and the placement might be helpful.
View past Ask Mr. Pest Control questions.
