Deer Warning Horns - Do They Work?

I don’t get it, acoustically. These little gadgets are supposed to produce an ultrasonic sound to scare deer. They come packs of two.
Some have no openings through which air can pass to establish a sound - as far as I know. It could be the air rushing by the sides producing a tone - not sure.

The package has no directions, and there is no specific distance the two “horns” should be placed. If the two horns work together, then the distance between them should not be arbitrary. OTOH, the two might work independently of each other. Any thoughts on this?

My dad has a couple of these mounted on the bumper of his pick’em’up truck. He hasn’t hit a deer yet. What more proof do you need?

Of course, come to think of it, he never hit a dear before he had the deer sirens mounted either.

All of the ones I’ve seen have a small hole and they supposedly work on the same principle as a dog whistle - high frequency squeal that only deer can hear.

Must be deer music…I wouldn’t understand!

Just don’t install them backwards or you’ll have every deer in the county chasing your car!

The Dave-Guy
“since my daughter’s only half-Jewish, can she go in up to her knees?” J.H. Marx

I hate saying something like this without having a cite or source, but. . .

“Some organization” tested them out a few years ago, and found that they didn’t do anything.


I’m really enjoying that mental image. Thank you.

I had one on a car when I lived in South Dakota. I hit and killed a deer so I concluded that it didn’t work.

I can state the following with absolute certainty:


  1. They don’t work.

  2. The deer I hit with my new car just before Thanksgiving was deaf.

  3. They do work and above/mentioned deer committed suicide.

Evidence available upon request (photographic)

Often wrong… NEVER in doubt

I can only add to this that Iowa State Patrol cars are equiped with “deer whistles”. I use them only because if they DO work, I’ll be glad I had them. Sort of like if Y2K disasters DID occur, I would’ve been glad I had that bottled water. If they DON’T work, at least they’re cheap and don’t stick out much.

Sweet Basil

A good friend’s sister mounted them on her car about a week before she hit a deer and virtually demolished the front end of the car - deer whistles and all. When she got out of the hospital, she decided not to repeat the experiment.

Computers in the future may weigh no more than 15 tons.
-Popular Mechanics, 1949

They work about as well as all the other ultrasonic repellers on the market. When did it become the rule that you can sell virtually anything as long as it doesn’t do harm and you offer a money back guarantee? Seems like it was a court case involving a baldness cure that set the precedent. Anybody know?

It seems like I read this somewhere, then again, I may have just made it up. To be honest, I’m not really sure. Anyway, it seems I heard that the horns can frighten nearby deer, causing them to panic. In other words, whereas the deer may simply pause and watch a horn-less car go by, a horned car may cause the deer to panic, try to flee, cross the road, and hit your car.

The claim of the whistle makers is that the gadget does not scare the deer away, but makes them stand still while they try to figure out what the noise was. If they happen to be standing on the road at the time, you might well hit them. On the other hand, the devices might not work at all. Deer are not especially bright or predictable, so it’s impossible to say if we’re hitting only the dumbest ones.



I’ve been pondering this since my previous post. I guess it’s akin to the eyes and snarling teeth on traditional fishing boats. Do they ward off misfortune? Who knows? Many old-time fisherman paint the amulets on their boats anyway. Maybe we should double up, and cover all bases. Paint wolf teeth on the deer whistles, glue a St. Chris between them, stick a mezuzzah (sp) next to the car door. By the way, I called the folks who make the deer whistles to ask if just one whistle would work. The chap said the two whistles make two different frequencies, so you need both. As amulets go, they’re pretty cheap. Have you priced a mojo hand lately? :wink: