Deer Whistles: Do They Really Work?

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This is a pretty in-depth study from a couple years ago. My company insists on putting these things on all of our vehicles. I think all of the evidence suggests that it's a complete waste of money!
While the Fall Riding Season has arrived, this is also the time of the year when Deer activity and incidents involving motorcycles seems to be at its highest level. While some riders have installed Deer Whistles, many of us wonder, Do They Really Work?

To answer that question, I consulted Fred Rau who not only is one of the most knowledgeable Motorcycle Journalists on the planet; he has put various models to the test and granted TheVOG.net the proper permissions to reprint his findings online.

The following is Fred's In Depth Review and Commentary of his experience testing various Deer Whistles designed for usage on motorcycles:

Animal Alerts…Proven Protection, or Myth?

By: Fred Rau 

Like so many motorcyclists, I’m a gadget freak. Heck, I’m even writing much of this story from my integrated-wireless laptop that packs up in the saddlebag of my bike.

People like us keep the lucrative motorcycle aftermarket industry booming, because we can’t just resist the latest gizmo that might make our riding more comfortable or enjoyable, or most of all, safer. This is why “Deer Whistles” have been so popular. I think I saw my first set way back in the early Eighties, and I freely admit I’ve owned several different types since then – some even chrome-plated!

I even tried to BS my wife into believing they were worth the extra $10 because the sun reflecting off the shiny chrome might serve as any extra warning to errant deer. What I didn’t bother to tell her is that Deer are essentially nocturnal, meaning you are most likely to encounter them when the sun is down. I still feel guilty about that!.

But over the years, as I got seriously involved in testing motorcycling products, and giving informational seminars at rallies around the country, the question came up more and more often:

“Do they really work?”

Once and for all, I hope to settle that question. A lot has been written on the subject, but basically, only in scattered and limited bits and pieces, or in scientific journals. So far as I can tell, no one has tried to put all the pieces together – until now. You will have to judge for yourself whether I succeed in my mission.

The Players and Their Claims

Though there are literally dozens of different kinds of “deer warning” or “deer alert” devices on the market, they can be broken out into two very basic categories:

1) Those powered by the passage of air, and

2) Those utilizing electronically-generated signals.

There are several sub-categories within these to generalities, but we will discuss them later, within the evaluation procedure.

For both types, the volume of anecdotal evidence supporting their use and effectiveness is impressive. Several different States’ Highway Patrol Departments use them on their cruisers. The U. S. Forest Service pays to put them on Forest Rangers’ vehicles in several national parks. More then one large interstate trucking company installs them on all their long-haul rigs, and the Internet is full of first-hand testimonials from both professional and amateur drivers, swearing to their effectiveness.

So persuasive is all this, that some insurance companies will even give you a discount on your car insurance for having them installed.

The manufacturers, for the most part, claim their devices produce “ultrasonic sound waves” that cannot be heard by humans, but which will startle Deer into either freezing in their tracks or darting away. Some claim to have scientific tests to prove this, but most rely on the anecdotal evidence mentioned before. A wise range of different frequencies is claimed by different manufacturers, as well as an equally wide range of distances at which they are supposed to work.

For starters though, let’s note that many of these claims list an “audible range” in large print on their packaging and advertising, but a much shorter “effective range” in the fine print or mounting instructions. Evidently, this means that though the Deer might “hear” your device from say, 2,000 feet away, as one manufacturer claims, this same Deer would not be prompted to react to that sound until your device was only 700 feet away (the “effective” range). And as you will read later in this report, even that is highly questionable.

Testing

At the beginning of this project, I decided to setup and perform my own tests on a dozen different animal-alert devices, which I purchased from motorcycle shops and over the Internet. Eight of these were the air-powered type, and the other four were electronic.

To help me with the testing and evaluation, I enlisted the aid of a professional animal behavior expert, employed by one of the largest and most prestigious zoological societies in the country. The actual testing was performed after-hours and/or somewhat scrumptiously in the back lots at a nationally-recognized wild Animal Park, but I can’t reveal the identity of the expert or the park. I’m sure that if the zoological society or the ASPCA found out we were intentionally frightening their animals, even in the name of scientific research, my co-conspirator would be fired, and I would probably be sued. I used two of the quietest and most common touring bikes I could think of, a Honda GL1800 Gold Wing and a BMW K1200LT as test bikes – carefully mounting the various devices as per their instructions (or as nearly as possible as you will see later), and then riding at or alongside various enclosures in which the animals resided. Tests were performed with varying groups of different species of Deer.

I am told there are more than 40 different species, but our tests only included the size most commonly found on the North American continent. My animal behavior expert observed the Deer from a nearby blind, using binoculars and a 500X video camera.

There were many more parameters to this testing, but I am not going to go into them here, frankly because I recognize that this wasn’t a very scientific methodology, and I don’t want to sound like I’m passing it off as a definitive test. It was not. There have been many other tests performed by people much more qualified and better-funded than I, and with much better equipment, as you will see. I could have simply relied on their extensive research to write this article, but I’m a skeptic from the “show me” state of Missouri, no less, and I wanted to “see it for myself.”

In the end, I was pleased to note that my own findings did not seem to contradict the truly scientific studies in any significant way. The professional, scientific studies upon which most of the article is based, collectively run more than 1,500 pages long and are admittedly, fairly dry reading.

Ultrasonic Air Whistles

By far the most common Deer Whistles in use are the original air-powered type which relies on the passage of ambient air through the “whistle” to turn a tiny turbine or pass over a baffle arrangement to produce a high-pitched whistling sound. These kind of sell for anywhere from $29.99 to $1.99 and quite frankly, I couldn’t find any significant difference from the higher-priced to the lower-priced units, except in the outward appearance. Air-powered whistles come in both ultrasonic (beyond the range of human hearing) and sonic versions, and single or dual (harmonic) tones.

The first I had ever heard of, and purchased, was called the Sav-A-Life. This company claims to be both “the original” and, “the only animal warning device field-tested with animals.” While they very well might have legitimate claim to bring the first with Deer Alerts in the U.S. (the devices were actually invented in Austria in 1979, and the Sav-A-Life was first marketed in North America in 1981), but they are far from being the only system field-tested with animals. In doing my standard background checks for this article, I came upon no less than six separate studies of such devices, performed by various professional scientists working for Universities, State Game and Fish Departments, national magazines and State Highway Patrol Departments.

Strike One for Sav-A-Life

Next, I looked into the two field tests touted by Sav-A-Life in their advertising (and often repeated by makers of knock-off Sav-A-Life clones). The first was conducted by the Institute of Applied Physics at the Technical University of Vienna, Austria in 1981. Far from validating the devices as useful animal warning devices, this study only confirmed that they actually operated at the frequencies advertised.

The second study was by the Finnish Experimental Institute for Forestry and Agriculture in Rhvehhari, Finland. This study’s final conclusion was that, “the duration of the tests was found to be too short to reach any definitive conclusions.”  The section of the study that Sav-A-Life likes to point to, which noted a “favorable reaction” involved domestic dogs – not wild animals. And even then, the study from Finland states that from all the experiments conducted, “It was unsure that the animals were not disturbed by the approach itself, so that the whistle sound was the only disturbing factor.”

After reviewing the findings of both the Austrian and Finnish studies, along with yet another conducted later in Switzerland, a scientific advisory panel from the World Society for the Protection of Animals states that there is no known data “that shows that such devices can actually stop and animal crossing the road, which is the main purpose of the device.”

Strike Two

And finally, I looked into the very basis for all of Sav-A-Life’s claims, namely that the devices produce “ultrasonic sound waves from 16,000 to 20,000 Hertz that safely warns most types of animals, yet you don’t hear a thing.” Well at least the Austrian study confirmed that the devices did, indeed, produced sound waves at the advertised frequencies, and it should probably be noted that some animals, such as dogs, would hear these sounds and probably react to them, as seems to be confirmed by the Finnish study.

But what do Deer hear?

In researching that, I found a lot of expert opinions that a Deer’s hearing range is “basically the same as a human being.” In a nutshell, it was found conclusively that common Whitetail Deer hear sounds from 500 to 12,000 Hertz, and, at elevated volumes, sometimes as high as 16,000 Hertz, but never beyond that. Since the absolute top end of a Deer’s hearing range is the same as the advertised absolute low end of the frequencies generated by a Save-A-Life Deer Whistle, the chances of a Deer actually hearing and reacting to one of these devices is virtually non-existent.

Strike Three

As far as the reams of anecdotal evidence go that is used by the promoters of some of these devices, the experts believe that most of it is a result of misinformation and lack of controlled conditions.

For example, many of those claiming they saw Deer react to their animal warning devices may have actual been seeing a reaction to the Deer sighting their vehicle, their lights, or even their lights reflecting off another surface, or perhaps the engine, exhausts or even wind noise of the approaching vehicle. They also note that anyone concerned enough about a possible Deer strike to have installed such devices would most likely, also be someone more likely to be alert and watching for Deer.

In response to the anecdotal evidence, I offer that the following entries have been unanimously concluded the total ineffectiveness of air-powered ultrasonic Deer alerts:

The Georgia Game and Fish Department

The University of Wisconsin at Madison

The University of Michigan

The University of Georgia

The Ohio State Police

The Utah State Police

Washington State University

The University of Connecticut

The Acoustical Society of America

The Insurance Institute for Highway Safety

The California Department of Transportation

Texas A &M University

Moving On

Now that we’ve (hopefully) successfully debunked the ultrasonic, air-powered whistles, let us have a look at sonic (audible) air-powered whistles, as well as some of the newer, electronic animal alerts. Sonic (Audible) Air Whistles I used the Sav-A-Life as an example of the air-powered Deer alerts because they are “the original,” and the most common type in use.

However, I also purchased seven other sets of air-powered Deer whistles for testing, and though most were nothing more than knock-off copies of the Sav-A-Life design, there were a couple that advertised a very different functionality, in that they produced sonic sound waves, of a type which can be heard by human beings.

Since, as noted earlier, it has been proven that Deer hear at the same basic levels as humans, these seemed to offer some promise. Once again, there are reams and reams of report pages on this subject, which you can look up for yourself, but let’s cut to the chase:

In both my own testing and that of several experts, it was found that the sonic air whistles could, sometime, and under ideal conditions, elicit a response from the Deer. However, there are many caveats and exclusions to that statement to wit:

1) The devices are airspeed dependent on operation. The slower your vehicle is traveling, the less audible the sound, and the shorter the effective range. No one could ever get a response from the Deer at more than about 60% of the advertised range, and even for that, the vehicle had to be traveling at over 70 mph. Yet the manufacturers, as well as every single expert in the field, advices that you slow down when in a known Deer grazing area. Also, at higher speeds, your available reaction time, should a Deer decide to stop out in front of you, is obviously decreased. And one more thing: Since none of the devices seem to operate at speeds below 35 mph, if you are riding at say, 45 mph, but with a 15 mph tailwind, your Deer alerts are not functioning at all.

2) If it is raining, the Deer alerts will either be operating at decreased efficiency, or not at all, depending on the intensity of the rainfall.

3) If you do not have a direct line-of-sight between your Deer alerts and the Deer – if there is a curve, hill, tree or any other obstruction in the way – the efficiency of the whistle will be severely degraded. And, when you think about it, if you can already see the deer, do you really need the alert?

4) Most of these devices produce a different sound from each of the two units, which must operate in tandem to produce a harmonic effect. To achieve that harmonic, they must be placed a specific distance apart – a distance which is not achievable on most motorcycles. However, even on bikes such as the GL, where there is sufficient distance available if the units are mounted on opposite sides of the fairing, they still aren’t going to work, because the manufacturer warns that there must not be any bodywork or other obstruction in-between the two whistles.

5) If any particle of road debris, dirt or even an insect becomes lodged in the opening of either one of the whistles, they cease to function. Most of the newer units can be removed, opened up and cleaned, but we all know how many bugs we get on our fairings and windshields in a few short miles of riding, so how long after cleaning do you think the whistles are going to continue to function? It’s a crap-shoot, at best.

6) Any ambient noise in the vicinity degrades the efficiency of the whistles. That can include wind in trees, or your own engine and/or exhaust noise. In my own testing, I found, through he use of a frequency-selective decibel meter (a recently calibrated unit of the exact same model used by the Federal Bureau of Standards and OSHA), that even the ultra-quiet Honda Gold Wing engine and exhaust “masked” nearly 50% of the deer whistles’ signals.

7) Even if all the conditions above are perfect (which I guess would mean coasting downhill with your engine off, with the deer directly in front of you and the whistles mounted on top of your windshield), in both my own testing and others, it was found that the deer would react differently almost every time. The best animal behavior experts say this is dependent on the time of day, the season of the year, the ambient temperature and the age, sex and physical condition of the deer in question. For example, a female that is either pregnant or recently gave birth is much more skittish than others, and more proneto fight. Or my personal favorite, which was verified by my own testing and several others: A young buck, during the rutting (mating) season, will aggressively attack in the direction of any offending noise. Several professional researchers barely escaped injury during their deer whistle tests when a large buck rammed the fencepost they were using to support the whistle.

Given all the above, it should be fairly obvious that even though the sonic whistles can, under certain, very limited conditions, be heard and get a reaction from deer, the chances of them actually doing you any good are extremely slim.

Electronic Alerts

It probably shouldn’t have come as any surprise to me that scientific research into the newer, electronic animal warning devices is practically non-existent. The few references to such devices I could find merely stated that, given that such devices did not rely on airflow to generate sound waves, and that most produced audible rather than ultrasonic sounds, that they “might’ have useful application.

Given that, from here on out you are going to have to rely on my own, admittedly unscientific test results, plus some research and interviews with animal and acoustical experts. I was able to locate five electronic animal warning devices meant for vehicle use, but I purchased only four, as one was obviously too bulky for use on a motorcycle, seemingly built for use on commercial trucks. Three of the four units were distributed by the same company, AA Communications, but after I received them, I found that only one of these was really weatherproof and appropriate for motorcycle use, their “AA Motorcycle Model Deer Alert,” which sells for $44.95.

The other I found was from an outfit called American Hornet called “The Hornet” (model V-120C), selling for $69.95. These two, then were the only ones I tested. As noted above, electronic alerts have a couple of obvious advantages over the air-powered types, in that they do not have to be moving through the air to operate, and they produce audible sound waves.

Another advantage I found, when going through the technical specs, was the sound pressure level (volume)  they developed. On the air-powered units, the maximum rating for most is 95dB, and we were never able to actually achieve that sound level in testing.

On the AA unit, the output was a true measured 95 dB, and the Hornet produced a whopping 120dB. In addition, there is a larger Hornet model, with dual horns, that produces a rated 135dB. The larger Hornet is rather bulky, and not recommended for motorcycle use, so I didn’t bother to order one. The average Whitetail Deer has a hearing range between 0.5 KHz and 12 KHz with a noticeable peak at almost exactly 4.0 KHz. On testing with our scientific sound meter, the operating frequency of the AA unit was 4.8KHz, and the Hornet was measured at 4.4KHz.

Obviously, both of these manufacturers have done their homework, and zeroed in fairly precisely on the best possibly frequency for alerting deer. Another big plus for these two units. In actual testing, the AA Motorcycle Model evoked a response from 70% of the deer approached. Some just lifted their heads or pricked up their ears, some moved away slowly, and some ran. None would have posed any thread to an oncoming motorcyclist.

The average range at which a response was detected was approximately 300 feet. The Hornet fared considerably better, probably due to its louder signal. A response was noted from 82% of the deer, and at an average range of nearly 500 feet. Again, the responses were varied, but non-threatening. On both units, since the output is in the human audible range, you can hear them when they are operating.

With the AA unit, I would have to get off the bike and walk in front of it to hear the tone, but with the louder Hornet, I could actually hear it while sitting on the bike, if stopped. Once I got moving, I didn’t notice it. However, both units come with on/off switches, and strong advice to only turn them on when in a rural “deer threat” area. That’s’ not just because you might find the sound annoying, but these units also produce ultrasonic sound waves of the type that can drive some domestic animals, like dogs, absolutely crazy.

The Bottom Line

Okay, so we now know that air-powered deer whistles are, for all intents and purposes, completely useless. And we also know that at least to of the electronic-type animal alerts work, at least after a fashion.

However, I must point out that that though these units elicited a response from the deer tested; remember what our animal behavior experts warned us about the varying responses we might expect due to the animal’s age, sex, time of year, etc.

We can’t rule out the possibility that one of these units, if used in the presence of a buck during the mating season, might elicit the same kind of “flight,” rather than the desired “flight,” response. And I think we can all agree, as motorcyclists, which could be a very bad thing.

In the end, the best advice is that which we’ve heard for years: When in an area known to be frequented by deer, slow down, and be alert. Scan the roadsides carefully, and if possible, avoid riding through such areas and dawn or dusk, when the deer are much more likely to be out grazing. And if you do see a deer or even just a flicker of movement somewhere in your peripheral vision, flash your lights and honk your horn. Even the people who make and sell the electronic alert systems admit that your vehicle horn is likely to be more effective than their deer alerts.

Of all the units tested, the Hornet was the most effective, but even that isn’t saying much.

Fred is currently on the road performing a 5,000 mile road test on the 2010 Can-Am Spyder RT-S. His ongoing reports can be found on this site by Clicking Here.

http://www.thevog.net/forum/thread/3439/deer-whistles-do-they-really-work-an-in-depth-report-by-fred-rau/

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