Re: Do deer whistles and electronic pest repellers really work?

When I want to find out about research on deer, I generally start with the Journal of Wildlife Management". It turns out that there has been a great deal of research on deer repellents, but not the type you're interested in. Researchers have instead looked at the response of deer to things like bone meal, capsaicin (the nasty ingredient in hot pepper sauce), human hair, mothballs and various commercial products designed to deter deer from eating your garden. Well, that makes sense--these folks want to manage deer--i.e., keep them away from valuable crops. So where to turn for information about preventing automobile-deer collisions? To a journal devoted to managing cars, of course (more specifically, the Road Management and Engineering Journal).

Various groups have tested the deer whistles you're interested in, as well as reflectors and various other devices designed to keep deer away from roads. Results are mixed, but deer whistles generally do poorly. Some researchers say that they do not make the noise they're supposed to and some say they only produce the noise under such limited conditions that they are practically useless. And even if they initially worked as well as the manufacturers claimed, the deer might become habituated to them over time, as has been shown in tests with reflectors. Check out the road management journal for a good summary of this research:

http:// www.usroads.com/journals/rmj/9705/rm970503.htm

As for electronic pest repellants, the story is probably the same (although I could not find any research on them). Anything that emits the same odor or sound or vibrations or whatever, but does not kill the pest, will not work for long. The animal becomes habituated to it, just like you become habituated to the sound of your car engine or the odor of the air freshener used in your office building. Obviously, if you are catching a mouse every night, at least that one animal is not the least bit bothered by the repellant.

To tell if it is the same animal every night (which is certainly possible; 600 feet seems like an incredibly long distance for something with such short legs, but warmth and chocolate chips, and perhaps a mate under the baseboards or a cat on the other side of the wall, are incredibly strong motivators), you would have to mark it. Researchers usually use something relatively permanent like Lady Clairol hair dye (yes, I'm serious), but given that your mouse is wild and probably not very cooperative, you could try a drop of nail polish (which would set quite fast and be very difficult to remove, although it's possible that the mouse might pull out a little fur to get rid of the smelly stuff). It's up to you to figure out how to drip nail polish or dye on the mouse without it having the opportunity to bite you--could you put it in a big, straight-sided bucket? Do NOT risk letting it bite you. Wear gloves and be careful. Good luck with this little "experiment"--I'd be curious to know the results.