Deer whistles

[Mark Stadnicki]

Do the stick-on deer whistles realy work? I can't seem to find any facts on them. We have a lot of deer (bambies) in Maryland + it's hunting season. I always drive slow on the back wooded roads and scan the best I can for them but they pop up outta nowhere sometimes. I see alot of cars with them on..?



Is there anything that realy works and not just gimmicks?

 

[Dingo]

Deer whistles don't work. I can get into the physics of it, but just trust me, they don't work. There are active electric versions, but even they are miserable at best. It's like honking your horn on the interstate. The people behind you can hear it great, but in front of you, it's damn near impossible.

 

[Michael Cacioppo]

Dingo, I don't quite understand your highway horn analogy. Since sound travels at about 1000 ft/sec and a car travels 88 ft/sec @ 60 mph. The front car certainly does not out run he sound waves. What am I missing here?



As for deer whistles I can only give you some anecdotal information. A small police force were hitting deer at a rate of about two a week. After installing the whistles the rate dropped to less than one per week. That doesn't mean much because the sample period and amount of vehicle miles may have varied.

 

[Dingo]

Sound radiates uniformly. It's not unidirectional like a laser. Because of your forward movement, most of it ends up behind you. A deer whistle is even worse, as the very nature of the deer whistle causes most of the sound to be made to the rear of the unit anyway.

 

[Thomas Rogers]

Dingo,



Mikes point and yours is that sound radiates in all directions uniformly as a concentric wave unless blocked by something, and it travels at some ridiculous speed (mach 1, or 770 mph). So if you have deer whistles mounted on a front bumper (for example) there isn't really any reason why there should be more 'sound' behind the vehicle...unless the vehicle is moving at >770mph. If anything, sound will be blocked by the vehicle if the whistles are mounted on the front bumper and there will be LESS sound behind the vehicle, not more.



Put bluntly the fact that the vehicle is moving has no baring on the sound travel.



TJR

 

[shawn stonbraker 2]

You know, both are good points. Wonder if Myth Busters would do a show on this.

 

[Thomas Rogers]

Stone, there may be other reasons why deer whistles are bunk (I think they are), but the notion that somehow you seem to outrun the sound and the sound end ups mostly behind the car is pretty ludicrous, IMHO. (no offense Dingo, and I apologize if that's not what you are saying).



TJR

 

[Dingo]

I'm not saying the vehicle outruns the sound at all.

I did a physics project on this very principle in college. It ended up at 24 pages.



Just humor me. Have a friend sit 6 car-lengths behind you at a stoplight, with both vehicles running. Have them honk the horn.



Then, have the same friend follow you on the highway at 70 mph. When they're 6 car-lengths behind you, have them honk again and compare the results.



Even assuming you remove wind noise and drivetrain/engine noise, you'll see the difference.

 

[Thomas Rogers]

Dingo,



I'll humor you.



I don't see how one can do such a experiment as you say and "assume" to remove the wind noise, road noise, engine noise, etc. Since one can't just assume those things away, I submit that they actually do provide the increased noise that washes out horn in the latter case.



But if you can give me a physics reason as to why movement alone of a sound emitting object can affect the observed sound level detected by another observer moving at the same speed, and same direction, then I'm ALL EARS (pun).



TJR

 

[Dingo]

Even though sound is a wave, it still degenerates over distance. Although the vehicle will not outrun the wave, the effective distance of the wave (half-life, if you will) is significantly reduced. Furthermore, these whistles are operated by air passing through them. They're not active amplified devices. Thus, the wave's effective distance is further reduced. In addition, the principle of the deer whistle assumes that deer care when they hear the sound. They don't. Furthermore, add the noise of the vehicle back to the equation, and they're just plain worthless.



Let me know if you need more:

http://cru.cahe.wsu.edu/CEPublications/eb1677/eb1677.html

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

http://advance.uconn.edu/2002/021118/02111812.htm

http://www.thecherrycreeknews.com/content/view/1678/104/

http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=ARLOFJ000004000003000071000001&idtype=cvips&gifs=yes

http://lutra.tamu.edu/klr/hearing.htm

http://www.startribune.com/lifestyle/homegarden/11310611.html

http://www.fayobserver.com/article?id=279964

http://workandfamilylife.com/sample_december2006/research1.html

 

[Thomas Rogers]

Dingo, I will look at your links, but I think moreso than any other reasons deer whistles are suspect by your last two points:

the principle of the deer whistle assumes that deer care when they hear the sound. They don't. Furthermore, add the noise of the vehicle back to the equation, and they're just plain worthless.

I've personally driven vehicles with and without deer whistles and several times with the whistles I have observed deer stop, mid-stride, cock their heads and perk their ears seemingly trying to figure out what the sound is they hear.



That is a far different behavior (observed, in limited sample, I admit) than the advertised action of the deer running in the opposite direction.



TJR

 

[Craig Childs]

I don't disagree with what you said, but wouldn't the noise of the car be affected by the degeneration of sound too? Therefore, it seems to me that the noise of the vehicle wouldn't really be a factor in the determination of the effectiveness of these deer whistles.



If the whistles were amplified, then they should be more effective than the air powered ones, theoretically, correct?

 

[Dingo]

Correct, Craig. On your first point, yes. That's why cars hit deer in the first place. The deer don't know they're coming. On your second point, yes.

 

[Thomas Rogers]

Dingo,



I reviewed all the sources I could load.



Here is what I found...see my commentary for each:





http://cru.cahe.wsu.edu/CEPublications/eb1677/eb1677.html



TJR: Indicates whistles are suspect because they probably can't be heard and probably don't disturb to the point of repelling. No mention of the sound not traveling as effectively in the front of the moving vehicle.







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



TJR: This article conjectured that at car speeds the whistles don't actually create ultrasonic level sound as advertised, and that it is unclear if deer can even hear ultrasonic sounds if they could. Again, no mention of sound not traveling as effectively in the front of the moving vehicle as behind.







http://advance.uconn.edu/2002/021118/02111812.htm



TJR: This article also discusses decible levels and whether or not deer can hear ultrasonic frequencies and if the whistles can produce said frequencies. Nothing about the movement of the vehicle detracting from the frontal sound wave emission.







http://www.thecherrycreeknews.com/content/view/1678/104/



TJR: Again, same as the last two...this article attacks the ultrasonic frequency generation claim of the whistles and not what you were describing, persay.







http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=ARLOFJ000004000003000071000001&idtype=cvips&gifs=yes



TJR: Again, this article simply disputes the ability of the whistles to generate ultrasonic sound.







http://lutra.tamu.edu/klr/hearing.htm



TJR: This discussed scientific experiments in which deer's ultrasonic hearing abilities were tested. Again, no indication of sound movement from a moving vehicle.







http://www.startribune.com/lifestyle/homegarden/11310611.html



TJR: No real meat at all in this one...just claims that there is no scientific evidence that the whistles work.







http://www.fayobserver.com/article?id=279964



TJR: Could not load this website.







http://workandfamilylife.com/sample_december2006/research1.html



TJR: Again, a general report that whistles are not effective.





So, to review:



The articles and sources above all agree (and many quote the same study) that no scientific evidence exists that deer whistles work; that the ultrasonic frequency level sound that these whistles are supposed to generate they don't; that deer don't hear ultrasonic level sounds; and that the decible level of the sound generated by the whistles is much lower than that of the car they attempt to protect.



I found nothing in the resources listed that a moving vehicle that generates sound somehow has more sound traveling behind it than in front of it.



It does say that car speeds and the whistles don't create ultrasonic frequency sound, but that didn't seem to be what you were describing.



TJR

 

[Thomas Rogers]

Dingo said:

Correct, Craig. On your first point, yes. That's why cars hit deer in the first place. The deer don't know they're coming.

I don't want to continue to sound argumentative, but I'm not so sure about that theory.



It seems to me that it might very well be that it is BECAUSE a deer hears a car coming that they dart out into the road to try to flee the oncoming sound and threat.



How many times have you seen a deer seemingly DART out into the road as you approach them? They are not unlike a squirrel...they hear you coming and they either run away from the road, or they run across the road....it's all a matter of which side of the road they think they want to be on when they take off.



Deer don't typically run unless threatened or playing. Deer typically walk during normal, daily routes that they take. They are effectively creatures of habit. The road they cross late at night is typically the same one they crossed, in the opposite direction earlier that day.



TJR

 

[Kevin Lang]

I am here in Maryland also, and the only time a deer collision has occured with me was when a deer lept out of the median once I was mostly passed it, and head-butted the rear right door on my 1992 LeSabre. No damage to either the deer or myself.



That was 05, and I haven't had many deer incidents since then, except now huge deer have started showing up on my almost-suburban streets in large amounts. My partner in crime (lol) was driving me back in his 1999 malibu, and we felt like we were only half the height of the deer.



Deer are a complete nuisance. They're not hunters, people--they're Wildlife Population Control Specialists. Let's allow them to do their job unobstructed.

 

[Dingo]

I don't disagree on any of your points. The articles don't reference my point about the degradation of sound, however, they do answer the initial question of the thread. Also please realize that the bulk of those articles are written by journalists, and not scientists. The fact that they don't include a point doesn't mean it's not there.



I think most of the reason that very little works on deer is that they don't know to be scared. They see/hear things that are unfamiliar. They can be scared, curious, etc. They don't get the memo that says they're supposed to be terrified and run away.

 

[Michael Martin]

Buddy of mine told me that they work real good! Yeah, when the deer hears it coming, they jump out in front of his car, car hits the deer, deer gets dead, and is held in place on the car by the stick on deer noise makers!



Somewhere out there is the tape of the guy calling 911 because the deer bit him on the back of the neck!

 

[Michael Martin]

Ahhhh! Here it is!

 

[Gypsy me]

I've always used them and they do work..IF you put them on correctly.