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Posted by Rich Higgins (Member # 3) on December 11, 2004, 09:41 AM:
to pinpoint source of sound.
Bill Martz and Steve Craig stated that coyotes cannot distinguish between volume and proximity. That is to say that they perceive loud sounds as being close and muted as being distant. I believe that a coyote can pinpoint the source regardless of volume. Agree? Disagree?
Robb Krause stated recently that coyotes hear on a horizontal plane. They cannot differentiate between sounds on a vertical plane. That is they cannot tell if a sound originates from the base of a tree or ladder or from the top. Agree? Disagree?
[ June 08, 2006, 11:22 PM: Message edited by: Leonard ]
Posted by albert (Member # 98) on December 11, 2004, 10:29 AM:
I believe that Bill and Steve are right. I believe this because I feel that louder volumes call more coyotes. Why because it thinks what ever is making the noise is close. I don't think that a coyote is smart enough to whether it has covered 1/2 mile or a mile. it just thinks that because of the volume that it is just over the next"hill". I have seen many coyotes walking past looking for the source of the sound. I feel that this happens quite often when howling.
I also feel that a coyote can reconize sound on it's vertical scale. I am quite certain that i have seen coyotes loking up in the sky looking for the source of the sound. geese fly crows cawing etc. The reason it may appear that it doesn't is that expierence tells a coyote that a rabbit making a distress sound is on the ground not up in the sky. So the coyotes limited logic tells it to look on the ground for a critter in distresss not in the sky.
Posted by varmit hunter (Member # 37) on December 11, 2004, 10:40 AM:
This is going to be like stepping into a Bear trap.
Rich, As you well know I open 98% of my stands with a wide open blast. Many times I have had one coming in wide open before I finished the first series. I am of the believe that you don't blow them out of the country.
I totally agree that they can" pinpoint" the location of the sound.
As far as the vertical goes. I have had many of them look up at me when calling from a tripod are tree stand.
Ronnie
Posted by Leonard (Member # 2) on December 11, 2004, 10:41 AM:
Hmmm? I disagree with the theory that coyotes rely on volume to judge distance. Seen that so many times, I don't know where to start? I believe they have a good fix on distance, when within reasonable proximity, regardless of sound volume. I don't think it applies from distances between ½ to a mile distant, but inside that, roughly, they know how far away is the sound, regardless of how loud it is.
Also disagree with Krause; no surprise there, right? In fact, I prove it to my own satisfaction when calling at night. If the sound is coming from a speaker mounted under my rear bumper, and I switch it to a speaker mounted above the cab, I can see the eye reflection much better, the closer I am to the light source and the sound source. In other words, they look down, eighteen inches off the ground, in one case, and the eye shine is indistinct. But, they look up, to the source of the sound, above the cab, and light up very brightly. They are looking up, and they are looking down, and don't have a bit of trouble telling the difference.
WHAT DO YOU THINK?
Good hunting. LB
[ December 11, 2004, 10:44 AM: Message edited by: Leonard ]
Posted by Tim Behle (Member # 209) on December 11, 2004, 01:06 PM:
A few years ago, I set up in a small valley. I put the caller at the base of a tree and the speaker about 8' up in the branches, then sat on the side of the hill watching.
A couple of minutes after the coyote puppy tape started, I had a wet bitch sitting on her butt at the base of the tree looking up.
She had to have known there was no way a puppy could get up a tree, but she ran right in and sat down to look for it.
I don't think most animals make it a habit to look up. But if that is where the sound is, they don't have any problem looking right at the source.
Posted by Greenside (Member # 10) on December 11, 2004, 01:25 PM:
Here's my theory:
Unlike humans coyotes can cock their ears independent of their head. This gives them the ability the pinpoint the exact direction of the sound in the snap of a finger. I would make a guess that it would be closer than a degree from a mile away. If you take a partner out howling to locate coyotes and after one responds, if on the count of three you both pointed to where you heard the howl, I think you would be lucky to be within 5 degrees of each other.
For the volume of the sound to determine location, I'm not quite sure.
I'm not a sound engineer but to a certain extent this is what I think happens. Sound attenuates(I think that's the word) or fads the farther it gets from the source. I'm not sure if you could straight line graph it, but this might be close if I give an example.
You start out on a stand calling loud, say 100 decibels and a coyote hears you from a mile away. At the mile distance he might be hearing only 10 decibels of sound as he starts coming to the call. You continue calling but gradually decrease the volume. When the coyote gets to the one half mile mark you are calling at 50 decibels and the coyote is still hearing the same volume in decibels as he started out with at the one mile mark. When he's at 250 yds you are only calling at 25 decibels and he's still hearing the same as when he started out.
I think that's one of the reasons we get hard chargers. The coyote thinks that because he's not hearing the sound volume increasing that he's not getting closer so he keeps charging till he runs right over the top of you.
The opposite of that would be if you kept calling at the same volume as what you started with the volume would be incresing as the coyote got closer to your your location. I think this is one of the reason coyotes start coming slower to the call. They know their getting closer and they start using their eyes and nose to locate your position.
If you are in a tree stand, the first kiss will get a coyote to look your direction, on the second kiss he'll look right up at you.
Dennis
Posted by Leonard (Member # 2) on December 11, 2004, 07:02 PM:
To offer another point to ponder. I can drive while playing distress sounds, and a coyote coming from either side will change direction, and wind up coming in behind the vehicle.
In other words, I am quite sure that a coyote can hear a sound, at a certain fixed volume, while at a fast trot. I believe it is quite reasonable that the coyote can be assuming that the distressed rabbit is running away from him, or something is dragging it away. Of course, they cannot reason, but I don't think they scratch their little head and say: "hey, that sound should be getting louder" or "that sound is way too loud." With the variation of wind currents, I believe that they aren't necessarily spooked by loud sound.
Good hunting. LB
Posted by Byron South (Member # 213) on December 12, 2004, 03:30 PM:
I absolutely believe that a coyote can pinpoint with pretty good accuracy where the call is originating from, even from a great distance. I have many times witnessed coyotes called from way out yonder with just one series blown from a call. Most of the time they come in a pretty direct route, unless there are terrain features that inhibit his forward progress. I don't think the volume has much to do with it other than it has to be loud enough for them to hear it. I don't vary the volume of my calling very much from beginning to end of my stands, with the exception of toning it down sometimes when I have one checking up fairly close. When I'm calling with a hand call I believe that emotion and desperation gets their goat more, than too much or too little volume. I'm not one of those that believes coyotes are spooked with to much volume, but I have seen coyotes spooked when they get very close to a speaker that is playing very loud. It's usually to late for him at that point though. I have gotten in the habit of muteing the call when I get one close. This sometimes makes them stop or at least slow down. Coyotes hearing is considerably more acute than humans. The coyotes ability to rotate their ears and the larger size enables them to detect and pinpoint sounds of reasonable volume from great distances whether the sound is up in a tree or on the ground. I don't use extra loud distress sounds unless it is windy, and I try not to hunt unless I have a client on windy days.
Answer:
1.I agree that a coyote can pinpoint the source regardless of volume.
2. I disagree that a coyote is limited by horizontal hearing.
Coyote are in FACT spooked by unpracticed shooters making loud BANG, BANG, BANG, noises at them.
Byron ![[Big Grin]](biggrin.gif)
[ December 12, 2004, 03:35 PM: Message edited by: Byron South ]
Posted by Leonard (Member # 2) on December 12, 2004, 04:23 PM:
Talk about looking up. I was making a tape, one time, in a local quarry, no hunting allowed.
For me, it was close and private, I didn't think about the possibility of calling a coyote in the middle of the day.
Well, I did, which was okay, just to work him and see his reaction, and vary the presentation, etc.
All was going nicely, until an airplane went overhead, and my only thought was that it messed up my recording. A quick look over at the coyote, and he was following that Cessna as intently as I was.
Good hunting. LB
Posted by Greenside (Member # 10) on December 13, 2004, 08:12 AM:
How many of you have had a turkey in a pasture or one that's hung up in a timber 40 yards in front of you? He's facing you, in full strut, and he throws his head straight out at you and gobbles. He sounds very loud and close. The next thing he does is spin 180 degress and gobbles again. His location and the volume of the gobble is the same as the first time, but this time he sounds like he's 100 yds away. If you couldn't see him you would probably assume he had moved away from you.
That's from a human perpective, but I think it might be very similiar to a coyotes.
IMHO, coyotes can be fooled if you keep that in mind. Howl directly at them with a megaphoned howler, then remove the megaphone and howl away from them. I think coyotes will hear that as two coyotes in two different locations even though the sound originated from the exact same place. Ones close and the other one is far off based solely on volume.
Shoot me down!
Dennis
Posted by Leonard (Member # 2) on December 13, 2004, 09:07 AM:
Not me. As a matter of fact, I use that method in my bag of tricks, when I have an animal hang up, mostly at night. I will turn and call normally, but 180º from the coyote's direction. I don't know the exact theory, but sometimes they decide to come closer. For some reason, I think it works slightly different than muting the volume. Just don't expect me to prove that it works. I have had that demanded of me before; it makes me cranky. ![[Smile]](smile.gif)
Good hunting. LB
Posted by R.Shaw (Member # 73) on December 13, 2004, 09:29 AM:
I agree with Dennis.
I believe from a long distance, the coyote gets a line to the sound. He travels that line until arriving at the source. The exact location is obtained when the coyote is much closer. Say 100 yards or less.
Gun fire scaring coyotes. If you have ever been shot at, there is a lot more associated with it than just a loud bang.
Randy
Posted by Steve Craig (Member # 12) on December 13, 2004, 09:55 AM:
"coyotes can not distingusih between volume and proximity".
Not what I said. I stated that Volume, EQUALS proximity! And this goes for lions as much or more than the other predators. You want to call more lions, increase your volume. Bears too! I have been from the old school that has always taught to start out quiet and then build and then back down again. I have since changed my thoughts on this reasoning, and have proven(to myself) beyond a shadow of a doubt that the louder I play my caller, the closer my target animals come in, and the higher success rates I have. A very good example is I have played the mouse vocalizations on my WT at full volume and the coyotes and fox still pour in on top of the caller. Yet I do not know of any 100 pound mice, but it sure sounds like one. Played at that level, it sure doesnt sound like any mouse I have ever heard. But it works and works well. Randy Shaw was just here for a hunt, and you can ask him what he thinks of this volume thing. I put 20 coyotes,6 fox and 2 bobcats in front of him and the only volume level I used was #5 and 6 on the WT. The two highest volume settings. I had both bobcats less than 30 yards from the speakers. Coyotes and fox ran up to the speakers and one jumped on it. I dont care what you use. If it works for you,Great! Keep doing it your way. This is what works for me and my success rates have gone up because of it.
As far as Mr.Krause's statement about them hearing or not hearing on a vertical plane.
His ignorance or inexperience is showing. Nothing wrong with being ignorant, it just means one doesnt know enough about a particular subject AT THIS TIME! I feel he needs a few more miles and critters under his belt before making such a blanket statement. What in the wide,wide, world of sports am I supposed to do with all those coyotes,bobcats, lions and foxes that come in and put their noses(or at least try too) in that speaker that I have hung 3 to 6 feet HIGH off the ground? (at full volume too! hehe) I guess Randy Shaw was not supposed to shoot that coyote that came in to my caller and stood on a shear cliff 75 feet high and looked DOWN at the speaker! You want to have some fun in the hills, and cliffs, use 2 WT callers and put one high and the other low and watch what a coyote will do. He will spot both speakers. Or maybe I was not supposed to shoot all those Indiana coyotes that came to my deer stands and looked UP at me in that tree 12 to 20 feet OFF the ground while blowing that hand call. Hundreds of them over the last 40 years. Or what about the hundred or so coyotes that died from looking DOWN at me over the river or creek bank there too! Coyotes,bobcats,fox and lions all will look up and will look down to locate the sound. This fact does come from years of experience and has the numbers and miles behind it to prove it. You guys are sure learning a few more tidbits about how to call more lions!
FWIW
Steve
[ December 13, 2004, 10:05 AM: Message edited by: Steve Craig ]
Posted by Bryan J (Member # 106) on December 13, 2004, 09:57 AM:
Great topic Rich, I love these topics that make me think about what I do and why. They raise questions in my mind as to how the coyote interprets my presentation.
Higher pitched sounds seem to work better for me. I believe this is the case because my set up almost requires a coyote to run me over. Higher pitched sounds are more directional than lower pitched sounds and I believe that the higher pitched sounds make it easier for the coyote to pinpoint exactly where the sound is coming from. I like to throw my distress sounds around like Greenside mentioned with the howls. I always thought that I was mimicking a flopping animal in distress. The changes that I make in volume I have always considered to be changing the level of strength and distress in the animal that I am mimicking. All in all, the only thing I know for sure is if a coyote doesn’t hear it they will not respond.
Posted by albert (Member # 98) on December 13, 2004, 12:06 PM:
I agree great topic, good answers.
Posted by Jay Nistetter (Member # 140) on December 13, 2004, 02:35 PM:
How do you explain why a good retriever looks up to scan the sky when he hears ducks or geese? Hmmm. More than once I've seen coyotes look up at ravens and crows when I'm sure they couldn't have glimpsed any movement. Where does the "vertical plane" begin and end? Is is one inch below the ground to 18 inches above? Three feet? 50 yards? And yes, I have had coyotes with their nose to the ground never once looking up at me, but have been busted by those that did.
I just cannot fathom that a coyote doesn't perceive loudness of source to proximity. Makes me wonder about what I see when a coyote is mousing. He hears a noise and abrupty turns and pounces on the precise spot where the mouse is (or darn close). If the sound were exaggerated, I'd bet money that the coyote would overshoot the potential meal.
Posted by keekee (Member # 465) on December 13, 2004, 03:15 PM:
Great topic!
I think predators do judge distance by sound. If the louder the sound the closer they are to the sound. I always tone my volumme down to work a predator, even grey foxes do the same thing. Good example....I can have a predator hung up say 60 yards away, I can tone down my calling and bring them on in sometimes, LB said this as well, I will turn around and call away from the predator, this to me, makes them think they prey is further away or another predator is leaving with its dinner. Same with howling. I have done this turkey hunting for a long time.
I also think predators can tell pretty close as to were the sound is coming from. I have been calling from tree stands, rocks, that give me good view points and had coyotes come in and look right up were I was right at me. So I also think they can point out the sound very well. I was seting in a deer stand a few years ago and seen a coyote cross a old growed up field, I always carry a call so I got the call out and started calling. The next thing I new I had another coyote seting 20 yards behind me looking right up the tree I was seting in. Im sure he was trying to figure how that rabit got hung in that tree! Till he seen me move and left, the first coyote came out of the brush on a run and when I lip sqeaked to stop him for the shot he looked right at me as I released the shot.
Brent
Posted by Byron South (Member # 213) on December 13, 2004, 04:42 PM:
R.Shaw,
I'm very familiar with what gunfire sounds like on the recieving end. I'm also aware that it will make a coyote turn wrong side out trying to make an escape. That line about the BANG, BANG, BANG, was an attempt at humor on my part .
I also agree somewhat with what has been said about a coyote getting a line on where the sound is eminating from, from a great distance. The closer they get to the sound the closer they are able to determine the excact position of the source, regardless of volume. Common sence is all that is needed to know that louder distress cries will reach more animals. You simply call a larger area with louder sounds. I don't however always find it nesasary to call a coyote from 2-3 miles a way. Don't like sitting there that long, and I absolutely hate late comers . If I was calling Lions as Steve, in big country, I would most certainly want to call loud because of the area needed to cover to get the attention of the more widely spaced Lions. For coyotes though, I believe any resonably loud call will be detected by coyotes as far away as I intend to call them from. In most of the area that I call. Coyotes in most of the areas I hunt have natural barriers that inhibit, and to a certain extent, prevent them from approaching from further than 3/4 to 1 mile away. In many of my spots the coyotes are inhibited from responding to my attempts from less than 1/2 mile. This is typical in the East (I live in East Texas). In most of the places that I call I'm within pretty close proximity to the target animal. If I were to play the distress call loud enough for them to hear it in the next county, they would hear it but not respond because they would have to be exposed to too many obsticles such as houses, county roads, open pasture. These coyotes are wired tight and are very hesitant about moving away from cover in the daylight. So in short it serves no useful purpose to try and call them from the next zip code. They won't come. Example: I recently obtained a new place to hunt here in East Texas. Its approximately 500 acres. I could easily get on one end and call my head off where every animal on the 500 acres and the surrounding properties would here me. Will this work to my advantage? Probably not. This place is mostly open hay meadow with brushy swampy patches of brush and trees interspursed all through it. Experince has taught me that I'm better off slipping into close proximity to these brushy portions and calling into them. Not real loud so as not to alert the coyotes at my next set 1/2 mile away and make my approach to it difficult. Did I mention they are very reluctant to cross the open hay meadow during broad daylight?
Summary: While I don't believe that loud calling will spook coyotes, I also don't believe that it is a great idea to crank the call to its loudest setting at every stand. Common sence, experience, and woodmanship skills have to play a role in detemining many of the things that seperate the "so so" callers from the consistantly successful callers.
Byron
Posted by Steve Craig (Member # 12) on December 13, 2004, 05:08 PM:
Byron,
I used to think just like you do! hehehe
I now believe that the 15 coyotes I used to call using my old methods have increased to 20 using the new! The lion has been one of the best teachers for me in this regard. Bill had been telling me this for quite a while, but old habits are hard to break, and sometimes we simply do not want to change, even when a change is for the better. Quite frankly, this principle applies to all aspects of our lives. Funny how we get into a rut and dont even know it untill someone or something or some situation wakes us up. I am enlightened! New situations and new techniques has opened a whole nuther realm for me to explore. Truely liberating! HeHe
FWIW
Steve
Posted by Leonard (Member # 2) on December 13, 2004, 05:22 PM:
Well, to answer the question of the moment, I fall on the side that high volume almost never is a negative. Where I hunt, I tend to crank it up whenever it pleases me. Lowering the volume, once your animal is relatively close can be a problem, especially if it is abrupt.
I just do not believe that a coyote is usually detered by too loud a volume. If they are, they usually let you know it, and I oblige. But, I have seen a lot of coyotes check up, for no other reason than I lowered the volume. Of course, at a certain point, they might check up anyway, but I try to be ready for that situation.
A lot of these habits of ours are probably due to the fact that we all hunt different looking terrain.
Good hunting. LB
Posted by Byron South (Member # 213) on December 13, 2004, 06:08 PM:
Steve,
Begging your pardon, I have always been open to trying new ideas, but have pretty much been self taught through trial and error . Hard knocks you might say. I have also learned quite a bit though from listening to those that have "been their done that". Steve, I respect you and your opinion very much because you fall into the catagory of "been there done that". I have never had the problem of limiting my learning ability by having a closed mind. If you could, please point to the part where you don't agree with what I said and liberate me. I am your clay .
As far as what bill smartz has to say, I could care less . I wouldn't take lessons on calling coyotes from him, and I sure as hell ain't taking any life lessons from him.
Your friend
Byron
Posted by Rich Higgins (Member # 3) on December 13, 2004, 06:20 PM:
Steve, let me burden you with my ignorance as well. Your statement "volume EQUALS proximity" to a lion or coyote still implies that a coyote cannot distiguish between loud and near or far and muted. If this is incorrect please edify me.
Posted by Rich Higgins (Member # 3) on December 13, 2004, 07:33 PM:
"I appreciate irony. I hope you do too, Steve. Robb's statement was based upon education, not ignorance. Since you are obviously unaware of his background please permit me to edify you. Robb has a degree in wildlife management and it is the scholar that submits these statements for our consideration and debate based upon such publications as follows. From Robb.
----------------------------------------------------------------------------
Robb sent me an email saying this:
""I didnt just pull that idea out of my rectal database of limited and biased observation(s). : )
Talk to your local/favorite "audiologist" on how your ears (and coyotes arent that much different) and hearing process and localization of sound sources works."""
---------------------------------------------------------------------------
In a nutshell, vertical location is more affected by experience and Tone of the sound, than by actual physical location. You can be fooled on the Vertical plane. BY COMPARISON Horizontal location is much more developed than what little vertical location abilities are and are used thusly, and if you read what a lot of these guys have written, it makes sense there too. Coyote comes in from wayyyyyy out there, and then after coming in, then, it looks up at the final closing distance. Which is interesting as well, since we are only talking about hearing ability, and in the some of the cases brought before us, (LBs airplane) would the coyote still "look up" if it was blindfolded and if so would it be looking directly at the plane ? In the case of the Jays Retriever dog, would he look up, even if the sound was coming from ground ?
The coyote's (Canis latrans) preference for use of three senses in hunting was: vision, audition, and olfaction, in order of decreasing importance (Wells and Lehner 1978).
heres a dry read, haha http://www.ie.ncsu.edu/kay/msf/sound.htm
and .........
This extract is lengthy but is a good breakdown of hearing process in general. Including overhead noises and interpretation there of. Other than the L shaped Canal, and ears that can move for more left - right configuration, canine hearing isnt much different than human hearing. (had that link and quote yesterday)
Physical Acoustic Perspective
When an acoustic event occurs in the natural environment, sound waves from that event propagate in all directions. The waves encounter objects in the environment with which they interact by reflection and diffraction. The constructive and destructive interference of all the resulting waves creates a rich acoustic admixture that is further enriched when there are multiple sound sources.
One of the potential objects encountered in the environment is a listener. At the listener's position, sound waves are arriving at different times and from different directions. As shown in Figure 1, there is typically one straight-line path along which the initial waves of each event first reach the listener. This initial direct sound provides the least compromised information about the direction of the sound event. Later, sound waves are reflected back from objects in the environment which arrive from many directions with many different time delays. This indirect sound provides information about the environment and the relative position of the sound event within the environment, especially its distance from the listener. For as long as the sound event persists, direct sound and indirect sound are simultaneously present and virtually indistinguishable.
Figure 1. Depiction of sound events in an environment. There is one direct sound path (thick line) between the event and the listener and many indirect sound paths (thin lines)
When a sound wave encounters the listener, there are two acoustic results depending on the frequency: 1) high-frequency energy is specularly reflected away, and 2) low-frequency energy diffracts and bends around the listener. In between, there is a transition band which is centered around 1500 Hz, the frequency whose wavelength is approximately equal to the diameter of the head. This acoustic phenomenon can be thought of as analogous to ocean waves hitting the piling of a pier: small waves bounce off of it while large waves bend around and go past it.
The sound waves that reach the listener's two eardrums are affected by the interaction of the original sound wave with the listener's torso, head, pinnae (outer ears), and ear canals. The composite of these properties can be measured and captured as a "head-related transfer function," HRTF. The complexity of the interaction of the sound wave with the acoustics of the listener's body makes the HRTF at each ear strongly dependent on the direction of the sound.
When a sound event is equidistant from the two ears, the sound arrives at each ear from the same direction and the HRTFs are very similar (but not identical due to slight asymmetries of the head). The region in which sound sources are equidistant from the two ears is called the median plane. (The similarity of acoustic information is often given as the reason why localization accuracy is poor on the median plane.) There are two other names by which researchers refer to planes in 3-D space. One is the horizontal plane which is level with the listener's ears. The other is the frontal plane (or lateral plane) which divides the listener's head vertically between the front and the back. These planes are illustrated in Figure 2.
Figure 2. Relationship of the median, horizontal, and frontal (lateral) planes to the listener's head.
When the source is not equidistant from the ears, the signal arrives at each ear from a different direction and the HRTFs are far from identical. The ear nearest the sound source is called the ipsilateral ear and the ear farthest from the sound source is called the contralateral ear. The position of a sound source relative to the center of the listener's head is most conveniently captured as a vector expressed in terms of two angles, azimuth and elevation, and one scalar, distance (see Figure 3). Azimuth is measured as the angle between a projection of the vector onto the horizontal plane and a vector extending directly in front of the listener. A progressive movement from 0 to 360-degrees would take the source completely around the listener's head. (There is no general agreement as to whether 90-degrees azimuth represents the listener's left or right.) Elevation is measured as the angle formed between the vector and the horizontal plane rising to 90-degrees overhead or descending to minus 90-degrees below.
Figure 3. Specifying the position of a sound event relative to the head in terms of azimuth, elevation, and distance.
Return to Article Table of Content
As shown in Figure 4, the signals arriving at the ear drums can be examined from two perspectives: the time domain and the frequency domain. If we imagine that the sound event is a simple impulse, we can easily identify the features that are dependent just on the acoustics of the listener. From the standpoint of the time domain, the signals that reach the two ears are no longer impulsive. The energy has been spread over 1-3 msec by the acoustic interaction with the listener's body. Comparing the two ears, the sound arriving at the ipsilateral ear is generally more intense and arrives earlier than that at the contralateral ear. These differences between the two ears are called the interaural intensity difference (IID) and the interaural time difference (ITD) respectively. When a sound source is completely to the side near 90-degrees azimuth on the horizontal plane, the ITD reaches a maximum near .7 to .8 msec.
Figure 4. Time domain and frequency domain representations of HRTFs for the ipsilateral and contralateral ears (adapted from Kendall et al 1990)
A comparison of impulse responses measured for different locations will reveal few significant patterns. But, if those impulse responses are converted to energy-time curves (similar to those of Hiranaka and Yamasaki 1983), more significant trends emerge. These energy-time curves, also called envelope functions, capture the dispersion of the impulse's energy across time (while omitting the waveform's positive and negative excursions).
Figure 5 shows energy-time curves measured at the eardrum position of the Kemar mannequin for 36 azimuth angles on the horizontal plane. Most significantly, one can see the variation in the delay of the initial sound that accompanies change of azimuth. Around 270-degrees (the far contralateral side), the symmetry of sound circling the head in both directions disrupts the pattern of the peaks. There are also clear patterns in the delayed energy after the initial peak. (The delayed sound reduces gain between 150-and 270-degrees, probably reflecting a reduction in sound from the pinna.)
In the frequency domain, Figure 4 reveals that HRTF magnitude profiles vary tremendously across frequency. Comparing the two ears, we see that the magnitude profiles are more similar for low frequencies than for high frequencies. The differences become increasingly noticable above1,500 Hz (the wavelength of the head diameter), because the head is increasingly effective at blocking waves at these higher frequencies.
Figure 5. Energy-time curves measured at the eardrum position of the Kemar mannequin for 36 azimuth angles on the horizontal plane. The curve at the bottom of the graph was measured at 0 degrees azimuth (front) and subsequent curves proceed by 10-degree increments completely around the head to 350 degrees (from Kendall et al 1990).
Plots of the HRTF phase are typically difficult to interpret. The phase function "wraps" repeatedly from - to +, because the time delays exceed the wavelengths of most frequencies. Much more significant information is revealed when phase is reinterpreted in terms of time delay, expressed either as phase delay or group delay. Phase delay captures the time delay of each frequency and group delay captures the time delay of the amplitude envelope of each frequency (see Smith 1985 for a more complete description). Figure 4 represents HRTF phase as phase delay. The delays are greatest for the lowest frequencies, because the diffraction of waves around the head causes the low-frequency waves to move more slowly than the high-frequency waves. Between 500 and 2,500 Hz there is a region in which delay makes a transition from a low-frequency region to a high-frequency plateau. The approximate center of this region lies at 1,500 Hz, clearly an important region for both magnitude and phase.
There are numerous acoustic factors which add complexity and richness to HRTFs. For example, there is a clear magnitude peak in the region around 3,000 Hz that is caused by the resonance of the ear canal. There are also notches and other fine details in the magnitude response caused by the constructive and destructive interference of the direct wave with sound reflected off the body. Reflected sound below 2,000 Hz is mainly from the torso and above 4,000 Hz it is mainly from the pinnae; in between there is a region of overlapping influence (Kuhn 1987).
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A comparison of HRTFs measured for adjacent directions will reveal many significant patterns. Figure 6a illustrates the patterns that can be observed in the magnitude response of the ipsilateral ear on the horizontal plane between 0- and 180-degrees azimuth. For example, the bandwidth of the spectral peak near 3,000 Hz widens as the sound source moves from front to back. A deep notch in the 8,000 Hz region migrates upward in frequency as the source moves toward the back and then virtually disappears. The 4,000 Hz region shows a deep notch between 100- and 130-degrees in azimuth. Figure 6b reveals related trends in group delay.
Figure 6a
Figure 6b
Figure 6. Ipsilateral HRTFs measured at the eardrum position of the Kemar mannequin for 19 azimuth angles on the horizontal plane: (a) magnitude response (from Kendall et al 1990), and (b) phase response expressed in group delay. The curve at the bottom of each graph was measured at 0 degrees azimuth (front) and the curve at top of each graph was measured at 180 degrees azimuth (rear).
These frequency domain profiles can also be viewed from the perspective of the differences between the two ears. Interaural intensity differences and interaural time differences vary in quite complex ways across frequency. Figure 7 shows the frequency-dependent interaural magnitude difference and the interaural time difference (expressed as group delay) for a single direction.
Figure 7. Frequency-dependent interaural magnitude difference and the interaural group-delay difference for a sound source at 90 degrees in the horizontal plane. (Original data was measured with the Kemar mannequin and then smoothed.)
HRTFs change very little when the distance of the originating sound event changes provided that the event is more than two meters away from the head. Beyond two meters, the sound wave from the acoustic event is approximately planar. (This means that HRTFs recorded at least two meters from the head can be utilized to simulate sound sources farther away, provided that environmental cues to distance are also present.) Less than two meters from the head, the sound waves from the acoustic event are more spherical, the effective angle between the sound event and the individual ears changes, and the HRTFs diverge significantly from those recorded farther away. Figure 8 shows a series of HRTFs recorded at varying distances directly in front of the head. The perception of distance close to the head appears to depend on these alternative HRTFs.
Figure 8. Magnitude response of sources located at 0 degrees azimuth, 0 degrees elevation, at distances of 90 inches (solid line), 24 inches (dashed line), and 4.5 inches (dotted line).
A comparison of HRTFs from different individuals will reveal that spectral features do not entirely match. The magnitude of individual HRTFs will vary in gross shape and as well as in details. Figure 9 compares the ipsilateral HRTFs of two individuals on the frontal plane. And although there are considerable differences in shape and detail, it can be seen that the overall trends are quite similar. For example, both individuals show the same trend in the upward migration of notch frequencies as elevation rises. This suggests that while individuals possess heads of different sizes and pinnea of different shapes, the acoustic processes that forge the individual HRTFs are the same. Nonetheless, interaural phase differences will be especially affected by head size because of the difference in the separation of the ears. The magnitude of interaural phase cues for children must be quite different from those for adults.
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Figure 9. HRTFs on the frontal plane for two subjects. The sound increases in elevation (solid-line: 0 degrees; long dashes: 10 degrees; short dashes: 20 degrees; and dotted line: 30 degrees) (from Kendall and Martens 1984).
HRTF Measurement Techniques
HRTFs are generally measured by recording test signals in one of three ways: 1) at the blocked entrance of the ear canal with a miniature microphone capsule, 2) within the ear canal with a probe tube, or 3) at the ear drum position with a dummy head. In all three cases, the head must be kept perfectly still during the measurement and environmental sound must be eliminated. The measurements made at each position have a stable, fixed relationship to measurements made at another position (Moller 1992). For example, measurements made with a probe tube placed at least 15 mm into the ear canal are closely related to those at the ear drum position. There is a fixed ratio between the magnitude spectra of the two up to around 7,000 Hz. Above 7,000 Hz (and sometimes below) notches in the two measurements are offset from each other and create push-pull spectral differences. (There is typically a poor signal-to-noise ratio in the notches which may cause inaccuracies when one transforms one type of measurement into another.)
Measurements made at the ears must be processed in order to isolate the part that represents the actual HRTFs. The acoustic signals measured at the ears can be represented as the products of the transfer functions of the source, S(w), and the recording equipment, T(w), with the ipsilateral ear, Hi(w), or the contralateral ear, Hc(w):
S(w) T(w) Hi(w) or S(w) T(w) Hc(w).
A reference measurement without a human subject is the product of the source and recording equipment alone, S(w) and T(w). Therefore, the HRTFs can be isolated by dividing the reference from the measurements in the ears:
S(w) T(w) Hi(w) = Hi(w) and S(w) T(w) Hc(w) = Hc(w)
S(w) T(w) S(w) T(w)
This computation is typically performed by first transforming the time-domain measurements to the frequency domain via the FFT where the complex-valued division can be performed directly. Alternatively, the complex valued frequency data can be converted to magnitude and phase, after which, the complex division is achieved by subtracting the gain in dB and the phase of the reference measurement from the ear measurement data. The impulse response for HRTF is then computed by transforming the frequency-domain HRTF to the time domain via the inverse FFT.
Psychoacoustic Perspective
A listener's judgment of the direction of an acoustic event is dominated by the sound that reaches the listener along the shortest, most direct path (otherwise the judgment of the direction of the event would be ambiguated by the indirect sound). This preference given to the initial sound is called the "precedence effect" (Wallach et al. 1949) or the "law of the first wavefront" (Blauert 1971). Even these initial sound waves are radically transformed in comparison to those of the original event. The sound arriving at each ear is spectrally modified by the HRTF, each ear has a different transformation, and the transformation changes as the head and/or the source moves. The auditory system performs the phenomenal task of integrating the information arriving at the two ears into a single, fused perceptual image of the acoustic event in space: the auditory system extracts out the directional information and reconstructs an estimate of the original source spectrum. This is accomplished in spite of the fact that there is no direct, structural representation of spatial information in the peripheral auditory system as there is in the peripheral visual system when light is focused onto the retina. (No wonder that research into three-dimensional sound has lagged behind research into three-dimensional vision!)
Classical psychoacoustics focused on the separation of the two ears and proposed the duplex theory of sound localization (Rayleigh 1907). Experimenters attempted to construct a theory of localization by compositing results from many experiments conducted with the ultimate acoustic building blocks, sine waves. These experiments demonstrated that interaural differences, that is, differences in the acoustic signals simultaneously presented to the left and right ears, strongly affect spatial perception. Interaural intensity difference (IID) and interaural time difference (ITD) each make a significant impact on perceptual judgments in a separate frequency range. Above 1500 Hz there is acoustic shadowing by the head and localization judgments are dominated by the intensity difference between the ears (IID). Below 1500 Hz the head is not a significant acoustic obstacle, there is a less significant intensity difference, and localization judgments are dominated by the time difference between the ears (ITD). (Consider too that above 1500 Hz ongoing phase differences would often exceed 360 degrees, making it impossible to judge time delay on the basis of these phase differences.) The differentiation in perceptual processing appears to be coupled to the acoustic properties of the head.
These observations do not, however, provide sufficient explanation for human localization. In fact, IID and ITD only affect the extent of the lateralization of the sound source, that is, its perceived position along the interaural axis, a left/right axis between the ears. With only ITD and IID, a person cannot judge whether an acoustic event is in front, above, behind, or below. This ambiguity of location at a given degree of lateralization has been called the "cone of confusion" (Woodworth 1954) depicted in Figure 10. It is now commonly accepted that the seeming uncertainty of spatial location on the cone of confusion is disambiguated by the complex acoustic profiles of the HRTFs. The classic psychoacoustic experiments supporting the duplex theory of localization did not utilized the frequency-dependent interaural magnitude difference and interaural phase difference typical of HRTFs. Then too, the duplex theory ignored the influence of alternative temporal cues above 1500 Hz such as interaural onset differences (see Blauert 1974 for a comprehensive review). Acoustic events in natural environments also exhibit ongoing perturbations that provide additional opportunities for grasping onto interaural temporal cues. The classical psychoacoustic stimuli were impoverished, and the results are only partially useful in understanding localization in everyday listening situations.
Figure 10. The cone of confusion (based on Woodworth 1954; adapted from Kendall et al 1990).
Modern psychoacoustic research has turned its attention to binaural hearing and the role of HRTFs in localization. In the broadest context, binaural means combining information from the two ears (as opposed to monaural which means using information from one ear or from each ear independently). Use of the word "binaural" also implies the kind of frequency-dependent interaural cues typical of HRTFs. This change in the focus of research is also accompanied by a shift toward the use of broadband stimuli, rather than sine waves.
Even though HRTFs are very rich in acoustic detail, perceptual research suggests that the auditory system is selective in the acoustic information that it utilizes in making judgments of sound direction. Evidence reveals that monaural phase information is irrelevant to spatial perception and that interaural phase information is extremely important. Wightman and Kistler (1992) have demonstrated that low-frequency interaural time difference is the dominant localization cue for sounds that contain energy below 2.5 kHz. For sounds that lack this low-frequency energy, interaural intensity difference provides the most likely basis for localization. It is still unclear though how much influence high-frequency time differences might have, since experiments have shown the time difference between the temporal envelops of high-frequency sounds are quite detectable (Henning 1974). Although the majority of research focuses on binaural cues, there is research into monaural spectral cues that suggests they are important for sound sources at the sides (Musicant and Butler 1985). There is also evidence that elevation in particular is influenced by the spectral content of the sound source itself (which is received at both ears), such that high-pitched/bright sounds are typically localized higher than low-pitched/dark sounds (Butler 1973).
There are important differences between the vertical and horizontal dimensions in the resolution with which people can resolve the spatial location of a sound source, an effect that Blauert terms "localization blur" (Blauert 1974). The highest resolution is evident in the horizontal dimension, especially in front of the listener where the minimum audible angle is 2-degrees or less depending upon the exact nature of the experimental task. That angle increases to near 10-degrees at the sides and narrows to near 6-degrees in the rear. By comparison, the resolution in the vertical dimension is quite low. The vertical minimum audible angle in front is near 9-degrees and steadily increases until overhead when it reaches 22-degrees. (See Blauert 1974 for a summary of research in this area.) Spatial acuity is apparently not as important for auditory perception as it is for the visual system.
While front/back discrimination is possible on the basis of the full acoustic information in HRTFs, it is also clear that head movement plays a dominant role in resolving front/back confusions (Wallach, 1940). This is particularly important for sound sources located near the median plane where other acoustic information provides few interaural differences. Figure 11 illustrates how the location of sound sources in front and in back of the listener, is disambiguated by a turn of the head toward the right. For the sound source in front of the listener, turning the head toward the right causes the left ear to receive sound earlier and with greater intensity. For a sound source behind the listener, it is the right ear that receives the earlier and more intense sound. Wallach's classic experiments also clearly demonstrated that dynamic interaural cues would override HRTFs when the two were placed into conflict.
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Figure 11. A dynamic head turn to the right disambiguates whether a sound source is in front or in back of the listener (adapted from Kendall et al 1990).
Individual Differences
There is debate at present concerning the impact of individual differences and the extent to which people can localize with HRTFs other than their own. HRTFs vary tremendously among individuals and interaural differences are strongly affected by differences in head size and in the size and orientation of pinnae. It appears that some individual's HRTFs improve other individual's localization accuracy (Butler & Belendiuk, 1977; Wightman & Kistler, 1989), but that large differences in head size can undermine localization (Morimoto & Ando, 1983). Wenzel et al. (1993) report that elevation judgments and front-back differentiation are more like to degrade with non-individualized HRTFs. At the same time, it appears that effective localization can occur in many cases in which the ears receive directional transfer functions (DTFs) whose details differ significantly from measured HRTFs. Kendall and Rodgers (1982) used low-order filters to create cartoon-like approximations of natural HRTFs while Martens (1987) and Kendall et al. (1988) describe the use of principal components analysis to create artificial DTFs. Comparison of results suggests the following:
1. individuals generally localize better with their own HRTFs than with those of others.
2. Some individuals have HRTFs that are superior and these HRTFs can sometimes improve the others' localization.
3. In order for one individual's HRTFs to work for another, the head sizes must be approximately the same.
4. Localization can be achieved with synthetic DTFs whose details differ from measured HRTFs.
Neurophysiological Perspective
Although neurophysiology is not part of the educational background of many computer music and audio professionals, it is an area from which many of the most important new ideas and discoveries about hearing continue to come. This is especially true for directional hearing. (For comprehensive reviews see Phillips and Brugge 1985; Casseday and Covey 1987; Kuwada and Yin 1987). Its terminology and perspective are quite distinct from physical acoustics and psychoacoustics. The purpose of this section is to familiarize the reader with this important context for understanding directional hearing and, in particular, to point out the special adaptations in the auditory system for sound localization. Although terminology is introduced somewhat gently, it is undoubtedly helpful if the reader has some basic familiarity with the field, especially the physiology of the auditory system.
Peripheral System
While the pinna is clearly adapted to auditory localization, the peripheral neurological system has little or no specialization for directional hearing. The peripheral neurological system transforms the acoustic ear signals into neural activity and seems most clearly designed to capture the spectral/temporal decomposition of incoming acoustic waves. The primary function of the signal decomposition would appear to be the identification of the sound source, i.e., the sounding object and its excitation. This strongly conditions the structure of the neural mechanisms that underlie human localization, since, at the level of the peripheral neurological system, source information commingles with spatial information.
The acoustic signal at the outer ear is converted to mechanical energy by the linkage of the ear drum to the middle ear (see Figure 12). This mechanical energy is converted to fluid pressure by the linkage of the stapes to the flexible oval window at the base of the cochlea. Stapes motion at the oval window initiates a traveling wave of displacement down the basilar membrane. As this wave travels, it is increasingly damped by the changing mass and shape of the basilar membrane. From base to apex, the wavelength lengthens and the velocity decreases. The extent of membrane displacement is related to the spectral content of the wave such that maximal displacement occurs near the base for high frequency components and near the apex for low frequency components. There are sensory receptor cells located along the basilar membrane called inner and outer hair cells which respond maximally at a characteristic frequency. These frequencies run from high to low along the membrane from base to apex and are arranged nearly logarithmically. Thus, distance along the basilar membrane is approximately proportional to the log of the characteristic frequency. In this way spectral information is spatially mapped onto a neurological representation. There is no spatial representation of location as there is in the peripheral visual system.
The motion of the basilar membrane causes displacement of the cilia of the hair cells and changes to the cell potential. The resulting potential can be viewed as containing an AC and a DC part. The AC part captures the temporal changes of the waveform itself. The DC part can be viewed as the average value of the potential over a period. At high frequencies, the DC part is the only response. For example, above 5 KHz the temporal structure of a sine waveform is not individually resolved (no AC part) and the inner hair cells respond only to the temporal envelope (captured by the DC part). Thus, the neurological representation of temporal information shifts gradually from the waveform itself at low frequencies to the signal envelope at high frequencies. (Thus, it appears that the most appropriate representation for time delay at low frequencies is phase delay and at high frequencies is group delay.)
Figure 12. Peripheral auditory system: (a) physical structure showing pinna, eardrum, middle ear, oval window, and cochlea; (b) conceptual representation of the uncoiled cochlea which is divided down the middle by the basilar membrane.
Neural Pathways
The basilar membrane creates a neural representation of the acoustic activity taking place in the physical world and this information is initially transformed and retained in the action potential firing patterns of fibers innervating (furnishing neural connections to) the basilar membrane from the cochlear nucleas (CN). These auditory nerve fibers bifurcate up to the anteroventral cochlear nucleus (AVCN) and down to the dorsal cochlear nucleus (DCN). (Follow Figures 13a and 13b for a diagramatic representation.) The goal of the central neurological system and subsequent neurological processing will be to construct a representation of information about the physical world that is useful for survival, information such as the identity of a sound source and its location.
Figure 13. Representation of the primary auditory neural pathways important for directional hearing: (a) projections to and from the superior olives (SO) constitute the heart of the binaural system; (b) monaural pathways and the integration of binaural information in the DNLL. Abbreviations are explained in the text.
At the beginning of the neural processing, the source information and the directional information are confounded. The most direct strategy for segregating the directional information from source information is to extract directional information from the differences between the ears, i.e., binaural information. The auditory neurological system forms symmetric left and right neural pathways for this binaural information. To simplify the discussion of these binaural pathways, we will trace the evolution of one path; same-side connections will be refered to as ipsilateral and opposite-side connections as contralateral.
The origin of the binaural pathways is the AVCN which is the source of projections to both the ipsilateral and contralateral superior olive (SO) (Stotler 1953). Projections in and out of the superior olive are represented in Figure 13a. The medial superior olive (MSO) is innervated by both the ipsilateral and contralateral cochlear nuclei. Its input is dominated by low-frequency fibers that retain the fine temporal structure from the basilar membrane. There is strong evidence suggesting that the MSO is a coincidence detector for interaural time differences (Goldberg and Brown 1968). The lateral superior olive (LSO) is directly innervated only by the ipsilateral cochlear nucleus. It is connected to the contralateral coclear nuclei through an intermediate connection in the contralateral medial nucleus of the trapezoid body (MNTB). The MNTB appears to provide an inhibitory input to the LSO. Both inputs are dominated by high frequency fibres. Evidence suggests that the LSO detects interaural intensity differences (Boudreau and Tsuchitani 1968).
The LSO and MSO project to and converge on two targets, the inferior colliculus central nucleus (ICC) and the dorsal nuclei of the lateral lemniscus (DNLL). This gives rise to the possibility that IID and ITD information is conjoined. Moreover, both ipsilateral and contralateral LSO project to the ICC, suggesting that information from both binaural pathways are combined, though only the ipsilateral projection includes LSO low-frequencies. The ICC is also the target of projections from the contralateral AVCN and the DCN. (See Figure 13b.) These projections contain monaural, rather than binaural information. In the ICC, the targets of the MSO and LSO lie within that of the AVCN and overlap with each other, giving rise to the possibility that monaural source information is recombined with binaural information. The ipsilateral DNLL projects to the contralateral DNLL (Figure 13b) providing a clear opportunity for integrating information from both binaural pathways which can then be passed on through projections to the ipsilateral and contralateral ICC. The DNLL is also connected to the greater superior colliculus (not shown in Figure 13) providing binaural auditory information with a path to motor centers.
The inferior colliculus has been the site of much work on IID and ITD. Research with low-frequency tones reveals neurons which respond to a "characteristic delay" (Rose et al. 1966). Similar results have been found with amplitude modulated high-frequency tones (Yin et al. 1984). The "phase locking" that occurs with the envelope of the high frequency tone is just like that of the low-frequency tones. Thus, there appears to be a single system of ITD detection that extends from the phase of low-frequency tones and to the envelope of high-frequency tones.
Although less clear in mammals, research with barn owls has shown that a spatial referent map of auditory space exists in the equivalent to the inferior colliculus (Knudsen and Konishi 1978). Individual neurons respond to acoustic stimulation from a narrow spatial region and neighboring cells respond to sources in adjacent spatial regions. Not only that, but azimuth is associated with ITDs and elevation with IIDs (Moiseff and Konishi 1981).
After the convergence of binaural and monaural information in the IC, pathways ascend to the medial geniculate body (MGB) and then the auditory cortex (shown in both Figures 13a and 13b). One might expect that a spatial referent map would be found in the auditory cortex of mammals. Instead, spatial information appears to be coded in the temporal firing pattern of a group of neurons (Middlebrooks et al. 1994). This allows spatial information to be projected on top of other neural maps
Posted by GUTPILE (Member # 448) on December 13, 2004, 08:44 PM:
If I read all of this, can I get a Diploma ? Crap, I don't have a clue !!!!
Posted by Leonard (Member # 2) on December 13, 2004, 08:45 PM:
Rich, that does nothing for me, even if you had not started out by suggesting that his opinion has more value because of his degree. At least, that's the way I took it.
What I will allow, is that calling from a ladder, with a coyote coming from a height of two feet off the ground, they most likely don't have that much of a clue, and make assumptions. Two feet high ground level or six feet off the ground amount to much the same thing, from a couple hundred yards distance.
Other than that, if the purpose of all those paragraphs was to convince me (or anybody else)that black is white; I know all I need to know about the subject, as a practical matter.
Good hunting. LB
edit: of course, I'm sure we all can agree with at least this much, since it is abundantly obviously:
"The LSO and MSO project to and converge on two targets, the inferior colliculus central nucleus (ICC) and the dorsal nuclei of the lateral lemniscus (DNLL). This gives rise to the possibility that IID and ITD information is conjoined. Moreover, both ipsilateral and contralateral LSO project to the ICC, suggesting that information from both binaural pathways are combined, though only the ipsilateral projection includes LSO low-frequencies. The ICC is also the target of projections from the contralateral AVCN and the DCN. (See Figure 13b.) These projections contain monaural, rather than binaural information. In the ICC, the targets of the MSO and LSO lie within that of the AVCN and overlap with each other, giving rise to the possibility that monaural source information is recombined with binaural information. The ipsilateral DNLL projects to the contralateral DNLL (Figure 13b) providing a clear opportunity for integrating information from both binaural pathways which can then be passed on through projections to the ipsilateral and contralateral ICC. The DNLL is also connected to the greater superior colliculus (not shown in Figure 13) providing binaural auditory information with a path to motor centers."
[ December 13, 2004, 08:50 PM: Message edited by: Leonard ]
Posted by Az-Hunter (Member # 17) on December 13, 2004, 08:52 PM:
After a cursory examination of the aformentioned text, it is my considered opinion that indeed; Rob DID, pull that material from the depths of his rectal database......
What a bunch of shit. Might it be, that a coyote tilts its head, to shift from the "horozontal" plane, and thus attain a perspective of the verticle?
Unbelievable................
Posted by Leonard (Member # 2) on December 13, 2004, 08:55 PM:
GIVE THAT MAN A CIGAR!
Posted by Duncan Menads (Member # 381) on December 14, 2004, 04:58 AM:
Boy, I was starting to wonder what Rich does to people who AREN'T his friends!
Vic, that's a perfect response. Like my grandpappy used to say, "You can try to educate some people, but dagnabbit, some of them are going to insist on being stupid."
Posted by Rich Higgins (Member # 3) on December 14, 2004, 05:04 AM:
"Rich, that does nothing for me, even if you had not started out by suggesting that his opinion has more value because of his degree."
Actually Leonard, I started out by suggesting that
"As far as Mr.Krause's statement about them hearing or not hearing on a vertical plane.
His ignorance or inexperience is showing"
missed the mark.
And before anyone questions my motive for posting this I will say that it was ONLY to stimulate interesting conversation?debate on this board.
Robb E-mailed me concerned that I was ridiculing him. Steve Craig probably thinks the same. You have your hackles up.
My mistake.
Posted by Steve Craig (Member # 12) on December 14, 2004, 05:40 AM:
No offence ment toward Rob. But if your basic premise is wrong, then all that data and all conclusions and all other peoples findings that are based on that premise is wrong too! Pretty simple really. I still stand by what I said. Just because one has an EDUCATION doesnt mean you can not be ignorant about a certain subject. He still needs more miles and critters under his belt to really understand what is going on. You still have to let the coyote be your teacher, he is a far better proffessor in the end. I can feel pretty confident that the coyote has not read any of that diatribe above. Cause he still can tell if the sound is coming from low or high. Not from extreme distance, but once he is in the general area, yes he can. How do I know this? He(the coyote) taught me. When you have to kill him to feed your family for most of your life, you learn a thing or two. Even today, he is still teaching me because I try to remain TEACHABLE. When ego's get in the way, teachability goes out the window. I am talking about heart knowledge, not head knowledge here.
As far as the proximity goes.
A coyote is a mile or so away. He hears my WT or my Higgins Howler being played at full volume. He percieves the coyote he hears as very close. And most of the time he comes to check it out.
Another coyote a mile or so away hears my WT or my Critter call howler being played at lowest volume. He percieves the sound as far away and he (most) of the time may not respond other than to answer the call. I prefer the first coyote as he is a much more aggressive coyote AT THAT POINT! Can the second coyote become more aggressive? You bet! How? Simply increase the volume. You really want to piss him off, just GO TO THE COYOTE! Get on top of him and play it loud and watch what happens. What happens is even if you play the sound at low volume, YOU HAVE MOVED TO THE COYOTE! You ARE closer and he percieves the sound as closer! Even on low volume, to a coyote, that sound is LOUD because he is closer to it! I am talking about using coyote vocalizations only here, to get the response I want.
Again, I DO NOT CARE WHAT YOU USE OR WHAT OTHERS USE. I dont care about how a coyote is SUPPOSED to hear. I dont care about long worded studies that can not be applied in the field. I care about how he RESPONDS TO WHAT I AM DOING. He is still the best teacher. I KNOW what works for me. All I ask is to TRY it. There is more than one way to skin a cat(or coyote) in this case.
FWIW
If it is worth nothing to you, then so be it.
Steve
Posted by Duncan Menads (Member # 381) on December 14, 2004, 05:47 AM:
Steve, did you read the article?
Posted by Leonard (Member # 2) on December 14, 2004, 07:35 AM:
Rich, I don't have any hackles up, at least for you.
As far as Robb, er, DuncanM <wink> I would recommmend that the information has almost no value, and any casual coyote hunter is wasting his time to read it again, or for the first time.
"You can try to educate some people, but dagnabbit, some of them are going to insist on being stupid."
Whether said by your grandpa, or some little fairy, <wink> that information has zero application in the real world. Therefore, I choose to be stupid, if that's the only two choices available to me.
Good hunting. LB
Posted by Steve Craig (Member # 12) on December 14, 2004, 07:53 AM:
Rich,
I dont have hackles. did away with them when I became a Christian. hehe Maybe it looks like it when I type, I dont know. We can argue untill the cows come home and in the end, we can agree to disagree on how a coyote makes,percieves, and computes sounds. No offence ment toward anyone and certainly none taken. In fact I think it is a good thing when these young whipper snappers get on here. Helps to put things into perspective. I gotta go with what Leonard said. His wisdom keeps shineing through.
Steve
Posted by Greenside (Member # 10) on December 14, 2004, 08:15 AM:
http://www.findarticles.com/p/articles/mi_m1511/is_2_20/ai_53631742
Dennis
Posted by Leonard (Member # 2) on December 14, 2004, 08:34 AM:
Interesting, Dennis.
At least it was concise. If we must depend on external clues to locate the source of a sound on a vertical plane, so be it. If a coyote were romping in to the call with a blindfold, we may have to concede a point, here and there. Otherwise, the theory has almost no relevance, for this kid.
Good hunting. LB
Posted by WolverineAtWork (Member # 23) on December 14, 2004, 11:09 AM:
quote:
We can argue untill the cows come home
I'm thinking that this has become the normal pattern of thinking on this and other internet boards. The question posed is one for which we have no concrete evidence to prove, or disprove.
Without there being a talking coyote who can provide firsthand experience or a scientist who has done exhaustive clinical research on the matter, the only thing that can be said is your opinion and your personal experience/observations to support it.
There are a few thus far, who seem to have taken the theories and articles presented by others as a personal slight, or an affront to all that they hold near and dear.
If you'd like to be taken seriously by all involved, not just those who share your point of view, then present your opinion as such and state what evidence you have, personal or otherwise. If we are unable to grasp the concept of simple discussion of the unknown, this is going to turn into another pissing-match which will only work to prevent such constructive discussion in the future.
</Rant>
<Opinion>
Now for my personal thoughts, strictly from a critical thinking perspective supported by my observations and the linked documentation presented in this thread.
The first (extremely long) article presents some really good information. I believe, however, that its application to canines is limited. Much of what I read in there really only applies to an animal whos ears are affixed to the side of its head and whos ears are stationary.
While humans seem to judge sound based on the volume and speed at which it reaches each ear, a coyote can turn its ears horizontally in the direction of the sound source, thus the sound can enter both ears simultaneously despite the coyote's head being oriented away from the source. This would also seem to affect the volume percieved by the coyote as well, considering the sound does not have to travel around the coyote's head before entering the opposing ear.
Now, I think we've all observed coyotes who were trying to home in on the source of a sound. My observations make me think that if a coyote needs to determine direction, he merely turns one ear away from the sound while keeping one ear trained toward it. This would provide a difference in direction and volume that he would need to proceed in the right direction as well as helping determine distance.
As to the ability of a coyote to hear sounds along a vertical plane, I would tend to believe that they either can't, or that ability is limited. Let me present this caveat first, these are my thoughts assuming that the coyote's head is stationary along the vertical axis. As soon as he tilts or lowers his head, his horizontal hearing would kick in and render the hypothesis invalid.
The article linked by Greenside made me think that because coyotes lack the pinna ridges present in the human ear, there may be a physiological limitation to their ability to hear sounds along a vertical plane. In considering the range of voluntary movement in a coyote's ear, I can't remember ever seeing a coyote position its ears in a manner that would logically allow it to hear sounds from above or below better without tilting its head.
Let's also consider the fact that sounds originating from above or below the coyote do not only travel along a vertical plane. Sounds bouncing off of the ground and other objects as well as the soundwaves naturally travelling horizontally from the sound source are also a factor. So, a sound source from directly above a "neck braced" coyote would still be heard, but may not be recognized as coming from above because he can't tilt his head to bring his horizontal "radar" into play.
These are my thoughts thus far. Does anyone have any experiences or observations that may support or contradict my theories? I would be happy to take them into consideration.
W@W <official snapper of the whippers> 
[ December 14, 2004, 11:34 AM: Message edited by: WolverineAtWork ]
Posted by Leonard (Member # 2) on December 14, 2004, 11:56 AM:
quote:
Let's also consider the fact that sounds originating from above or below the coyote do not only travel along a vertical plane. Sounds bouncing off of the ground and other objects as well as the soundwaves naturally travelling horizontally from the sound source are also a factor. So, a sound source from directly above a "neck braced" coyote would still be heard, but may not be recognized as coming from above because he can't tilt his head to bring his horizontal "radar" into play.
I considered that part, myself. But, this discussion has not degraded to the level of a pissing match, in my view. I do see it as nothing remarkable, no real useful information, because it seems to apply to every receiver of sound that has ears mounted on the sides of their heads, which, according to Darwinian theory, would be the best place for them. Show me an example that bucks the trend. Grasshoppers?
Good hunting. LB
Posted by WolverineAtWork (Member # 23) on December 14, 2004, 12:35 PM:
For a carnivore with few natural predators to worry about, the best place would seem to be forward allowing pinpoint location of prey. For omnivores such as humans, apes, etc., the side of the head would offer a combination of predatory advantage as well as defensive capability.
In terms of practical application of the information presented, I believe that it has its usefulness. Having hunted from a ladder and had coyotes run right under the ladder looking for a meal, I tend to believe that they have a difficult time pinpointing the location of sounds coming from anything other than ground level.
In addition, I've had coyotes stand and look at me sitting on a ladder as if I were no threat. My personal opinion of this experience is that they don't have too much to worry about from things in trees, so why sweat the shiny smoking stick moving in the....FWAP!!! <grey matter flies> I don't want to imply that hunting from an elevated position is the "brass ring", nor do I want to come off like I'm the expert at it. But, it certainly has its merits. The question now becomes, why does it have its merits? Hence the discussion at hand.
[ December 14, 2004, 12:36 PM: Message edited by: WolverineAtWork ]
Posted by Leonard (Member # 2) on December 14, 2004, 12:52 PM:
Well, their visual receptors are mounted in a forward orientation, not on top of their head. I wouldn't deduct points just because 99.9% of their prey walks on the ground, at least occasionally.
The ladder argument is a little overused, unless the hunter is actually calling from the ladder with the coyote in plain sight. Otherwise, any responder is likely to focus on the expected; an animal in distress, on the ground. They are, I hope we can agree, a sight hunter, first and foremost.
Good hunting. LB
Posted by Barndog (Member # 255) on December 14, 2004, 03:06 PM:
A very good article on the coyote
The Journal of the Acoustical Society of America -- May 1997 -- Volume 101, Issue 5, pp. 3163-3164
Check it out, may solve some debate.
Posted by Steve Craig (Member # 12) on December 14, 2004, 03:29 PM:
Interestingly enough, my son and daughter in law took a hot air ballon ride this morning for their aniversary. They told me they flew over 4 coyotes and several deer and every coyote looked up at them and then ran and hid under some brush. The deer did not know they were around.
I was using a ladder 25 years ago out on those big Illinois and Indiana corn fields to call coyotes. No trees for sometimes miles in any direction. They looked up then and they will look up now if you give them a reason to. As long as you dont move, you will be safe even if you make a noise and they look at you and see you. The point is they still will look at where the noise came from. Be it up or down. The only time I have ever noticed a coyote cocking its head back and forth or side to side was when it was looking intently into my WT speaker. I have never seen a bobcat or lion do this however. Fox will do it though, as will dogs.
Steve
Posted by Tim Behle (Member # 209) on December 14, 2004, 04:12 PM:
Can some one here enlighten me? I seem to be missing a very relevant part of this discussion.
What difference does it make if a coyote can or can not hear on a vertical plane?
You only have to call them into shooting range. I don't know of anyone who tries to call them into clubbing range. So who cares if the coyote knows if the sound is coming from above or below? As long as he shows up and stops broadside in a place that gives me an easy shot, what else could I ask for?
Posted by Rich Higgins (Member # 3) on December 14, 2004, 04:53 PM:
You're absolutely correct, Tim. When a coyote approaches the caller it doesn't matter what it weighs, it's color, it's sub-species, sex, age, or health. But all those have been interesting topics of discussion after the fact.
Posted by Jay Nistetter (Member # 140) on December 14, 2004, 05:14 PM:
Tim,
In my earlier days I used to go Coyote Clubbing.
They all look prettier at closing time.
[ December 14, 2004, 05:14 PM: Message edited by: Jay Nistetter ]
Posted by Tim Behle (Member # 209) on December 14, 2004, 06:31 PM:
You surprised me, I was betting that Rich would answer first, but I would have bet he would have used Jay's reply.
As long as I don't have to worry that they coyotes are going to quit coming to my calls, because I'm holding the call at the wrong angle, I'm happy.
Hey Jay, care to start a topic on coyote clubbing? I got one so bad one time the cops came out in the middle of a blizzard and made me leave her house and go home. ( And I was in Steve's hometown!)
Posted by Jay Nistetter (Member # 140) on December 14, 2004, 06:44 PM:
Clubbed me a mangy old coyoe one time and took her back to the den. A few days later my Dad called me and told me that the ugliest coyote he ever saw come looking for me. I was totally busted.
Posted by Leonard (Member # 2) on December 14, 2004, 07:10 PM:
How much did that set you back, Jay?
Posted by Tim Behle (Member # 209) on December 14, 2004, 07:14 PM:
I had one get pissed at me, because when I sobered up and saw her face in the morning, I ran out and wouldn't return any of her calls.
Two weeks later, she called my Mom and told her to have me call her to discuss her pregnancy. ![[Eek!]](eek.gif)
Some of them coyotes are not only ugly, but they can be pure evil too!
Posted by Leonard (Member # 2) on December 14, 2004, 07:23 PM:
Robb is going to throw a hissy fit if you bad boys don't knock off all the happy talk and get back on topic! ![[Roll Eyes]](rolleyes.gif)
[ December 14, 2004, 07:31 PM: Message edited by: Leonard ]
Posted by Jay Nistetter (Member # 140) on December 14, 2004, 07:24 PM:
Leonard, Hissy?? That's all my dad ever said about it. Never frowned nor cracked a smile. Issue never came up. That alone was worse than anything else. Come to think of it, she would never look up either and every time another dog was in the area, she'd start growling and all territorial and stuff and run the others off. She had some vertical hearing deficiency. Could have had something to do with the way her ears were shaped. I dunno.
Tim, so how did the EPT work out? I know they can get pretty viscious. Probably best to get 'em after the teeth fall out.
[ December 14, 2004, 07:31 PM: Message edited by: Jay Nistetter ]
Posted by Steve Craig (Member # 12) on December 14, 2004, 07:30 PM:
Geez Tim,
Only 20 people live in my home town. Must have been one of my cousins! hehe the cop was probably my uncle as well!
Steve
Posted by Az-Hunter (Member # 17) on December 14, 2004, 07:49 PM:
Rob; yer pappy was a wise old bird, you should take his sage advice to heart. Pull yourself away from those gawd awful, boredom inducing manuscripts you submerge yourself in, and get out and kill some coyotes. You can experience for yourself the joy of watching the inately adaptable coyote, look up,down,sideways,backwards or between his legs to pinpoint the sound it hears.
My own dear departed father, used to grin and warn me of the existence of "educated idiots", and all thru my adult life, Ive seen many times what he was talking about. Go hunting pal.
Posted by Tim Behle (Member # 209) on December 14, 2004, 07:56 PM:
Steve,
Aren't you from Rockville? Remember Fat Freddie's Saloon on the East side of town?
I use to live in that place on the weekends!
Posted by Duncan Menads (Member # 381) on December 15, 2004, 04:42 AM:
Steve, for once I agree with you. Bring on the whipper snappers! It's fresh air in a room full of stale old farts.
Vic, for the record, you're way off. And for the record, it was my GRANDpappy with those words of wisdom. Since he was walking this earth well before the LAST turn of the century, his words should carry weight around here. All you have to do is say you're old and people here are supposed to respect you, right?
I don't know, Vic, it sure looks to me like Robb has killed a few coyotes lately. If anything, it seems his partnership with the Higgins Clan has put a bit of fur in front of him. Now that you bring it up, just how much better COULD he do than to team with Higgins??? I can't seem to find much better mentor on this board, anyway, as well as a few other boards.
As far as education, yes, sadly, I've seen monkeys literally beaten to death trying to be taught the simplest things. Like my grandpappy used to say, sometimes you can't train a monkey to be anything more than a monkey. Banana?
Oh, I almost forgot: Vic, I've been told you are one rightly handsome man. Hope you have a wonderful holiday! (actually, that's for real).
(Leonard, does that count?)
Posted by Steve Craig (Member # 12) on December 15, 2004, 04:58 AM:
Tim,
Nah, My wife is from Rockville. She graduated from Turkey Run. Me, I m from a bit further north. Little town called Veedersburg. Graduated from Fountain Central. When I started trappping and hunting for a living, I lived in Kingman. About 20 miles north of Rockville. I do remember the bar, but had forgot the name. I think it is called The 36 Tavern now. Interesting enough, my wifes step dad was one of the Rockville police!
Steve
Posted by Greenside (Member # 10) on December 15, 2004, 06:02 AM:
My guess is that a coyotes perception of distance might be more crude than some people think.. How else could you explain a coyote running under a ladder? If he had the distance pinpointed to a gnats ass he would have stopped under the ladder!
Dennis
Posted by Rich Higgins (Member # 3) on December 15, 2004, 08:41 AM:
W@W, he sure has been terrorizing the local pops. 60 coyotes since Sept is pretty good for a weekender.
Posted by Leonard (Member # 2) on December 15, 2004, 09:05 AM:
Duncan, yes, thank you. That qualifies. Wasn't so hard, was it?
Fact is, Robb K is a confirmed troll, along with a few others (you know who you are) that get their jollies by poking others in the eye, via the Internet. Eternal vigilance.
Yeah, he's killed a few animals in the past few years. Good for him. But what limited success he has enjoyed is due, in part to his association with Higgins, and some personal hard work; not the book learning being talked about here. You need to gain experience in the field, and do the scouting, after you close the book; otherwise it's all theoretical. And, (if I may add) to smugly ridicule the efforts of those that learn their skills and knowledge by trial and error, and then innocently share what they know, and what has helped them....well, that's pitiful, in my view. That respect usually comes from growing up, so maybe there is hope? He get's more ink here than he deserves, that's for sure.
Good hunting. LB
[ December 15, 2004, 09:45 AM: Message edited by: Leonard ]
Posted by DAA (Member # 11) on December 15, 2004, 10:10 AM:
I think you're right Dennis. At least from any kind of distance. I'm sure most of us have had numerous occasions where a coyote would have literally run us right over if we hadn't shot first. Likewise, we've all had them come in more slowly, obviously looking all over for the source as they come. Often perking up, adjusting course and picking up the speed with a little encouragement in the form of a squeak.
My feeling is that they are super good at getting a line on a sound from some distance, but depend on being able to see what is making the sound to pinpoint.
Not exactly a new or profound thought.
- DAA
Posted by Leonard (Member # 2) on December 15, 2004, 10:42 AM:
Yeah, I tend to agree with you both, in a lot of situations.
But, if we think about it, sometimes the running right through the stand is when we aren't actually calling, at the moment, or when using a remote speaker. Not always, but that can explain a coyote's confusion. If we portray coyote behavior/response, as something resembling a blind bull in a china shop, that isn't accurate, is it?
Main thing is, a small scenario, if you will?
A coyote is coming in, but he is pausing every so often, as they do. So, he stops momentarily, at the crest of a hill, looks around, hears a very loud machine, but doesn't see the speaker, and he still knows that the distressed animal is 100 yards away, not ten feet.
If, on the other hand, that volume is at the very lowest setting, and you might think he can barely hear it....he does not think the distressed animal is over a half a mile away. He knows the sound is 100 yards away. He probably has the location every bit as accurately as your GPS.
Now, this doesn't begin to cover every possibility, it just simplifies the debate. Just about everybody, at one time or another has had a fox or coyote run right up to them. So, he misjudged things, in his haste, which is understandable.
I will mention something I observed, (again) that shows me that there are other factors involved, other than acute pinpointing the prey/distress. I watched two coyotes engage in a breakneck race, coming to the call, when one tripped and fell, turned a complete somersault, and lost no ground to the trailing animal.
Hot pursuit can alter perception, I think it can be that simple.
But, I don't pretend to know everything. Good discussion!
Good hunting. LB
Posted by 22-250 (Member # 36) on December 17, 2004, 10:03 PM:
I am with Craig on the volume, the louder the better. Not that I have the experence as Leonard or Rich. However, I use to start really soft and take the volume up. But I have notice that the louder the volume more action I get. This is true with foxes, coyotes and bobcats. I also use the loudest volume on mouse or rodents calls. In San Diego areas that I call in are hit hard by other hunters. I have found that the harder the areas are hit, the more I can call in with the high volume. In addition, I always use a decoy.
I do not see as many coyotes as the Arizonia hunter do, but San Diego has very limited areas for hunting. I have talked to a lot of hunters in San Diego, and most of them can not believe that I call in as many coyotes in the areas that I call.
[ December 17, 2004, 10:04 PM: Message edited by: 22-250 ]
Posted by NVWalt (Member # 375) on December 18, 2004, 06:54 AM:
About them there coyotes hearing and pinpointing the sound. All I do know for sure is when I am out calling and a coyote is comming in he sure makes a beeline to me whether I am high on some rocks or low on the ground,up on an overlooking knob or down flat in the valleys. He comes in and unless he checks up a hundred or so yards out,and he still is looking right at me,and I do my part shooting ol Mr. Canis Latrans is toast.That's what I see out there when I call..NVWalt
Posted by Western Rifleman (Member # 393) on December 18, 2004, 09:49 PM:
Leonard . . .
At Long Last -- SIMPLIFIED and WELL SAID!
Now I FINALLY Understand!!!
I was praying for clarity.
Thanks again . . .
Cas in Wyoming
Posted by Leonard (Member # 2) on December 18, 2004, 10:33 PM:
Good job, Cas. Where do I send the check?
Good hunting. LB
Posted by Rich Higgins (Member # 3) on December 19, 2004, 07:03 AM:
AND good perception, Cas. Now you know why I hang on his coattail.
(Leonard, you know my address.)
Posted by Leonard (Member # 2) on December 19, 2004, 11:38 AM:
Total BS, Cas!
Actually, I hang around Higgy just waiting for the occasional pearl of wisdom, as my reward.
I'm just a recreational coyote hunter, just like the rest of you; hardly a guru. I've never even appeared in one of those "Camo Videos".
<sniff, sniff>
Good hunting. LB
Posted by Rich Higgins (Member # 3) on December 19, 2004, 01:26 PM:
Total BS, Cas. Leonard has appeared in Nistetter's underground video as the sheep whisperer, a John Holmes reincarnation. I've videoed him for a Masters of the Call segment, and, if we can all put a little pressure on him, he may do a NIGHT CALLING segment for the video. He is still pondering how much info to divulge, but I think he has agreed in principle
Posted by Krustyklimber (Member # 72) on December 19, 2004, 02:49 PM:
Wow...
Krusty 
Posted by Western Rifleman (Member # 393) on December 19, 2004, 06:43 PM:
Geez guys . . .
Such company I am blessed to be with --
HARK and FORSOOTH!!
Guess it just doesn't get any better or more fun. :-) :-) :-)
I've just GOT to see the aforementioned video!!
:-) :-)
Posted by Doggitter (Member # 489) on December 25, 2004, 07:45 PM:
It feels like I give coyotes more credit for brains than most of you. I think they definitely use volume as a distance/locating method, but I also feel that use windage/elevation at the same time to find a meal. We don't use just volume or vector to locate, no reason to assume that they're lesser beings so they can't do the same. It's the balance between the two methods that make them so efficient at what they do. If coyotes used volume only to determine distance they wouldn't have evolved with those rotating ears that works so well. They'd be fixed and have to move their head instead. I watch my pup all the time trying to find the bull elk coming out of the TV speakers. Has a hell of a time but looks all over in the direction it came from. Behind, above everywhere but inside the box. He knows an elk can't be there. Just one aspect of where the tools dogs have to use come together. Loren
Posted by Wiley E (Member # 108) on December 26, 2004, 07:30 AM:
Higgens: "Leonard has appeared in Nistetter's underground video as the sheep whisperer, a John Holmes reincarnation."
ROTFLMAO!!!!
That's a good one!
To the discussion at hand. There is so many variables to consider in how coyotes hear sound. Let me share with you some personal observations for you to apply to this discussion.
When calling on snow cover with white coveralls, I have been run over by coyotes more than at any other time. Why? I believe it's because the coyotes have a perfect line on the sound but they simply do not know the distance and they cannot see or smell what they heard so they just keep coming.
Let me add some more useful information to this observation. These coyotes usually came from quite a ways in rougher country. Because they were still coming, I didn't see the need to continue calling. BUT, I would bark at them ata about 75 yards to get them to stop and they still kept coming.
Now think about that, a loud sharp bark yet they still keep coming. If they completely trusted their sense of hearing, they would stop but it has to be confirmed with their eyes or nose or at least by their seeing an area that would hide what they heard.
That's when I started wearing a dark glove and all I had to do was wave it at them to get them to stop. Eventually I just left my face exposed to stop them and moved my head. When they got within range to distinguish my ugly mug, POP FLOP, I owned them.
Now let me give you another observation I have seen many times. When calling from a bare grassy knob that would not hide a coyote or a rabbit, I have called coyotes in that would just stand there looking at the hillside at about 200 yards as I was calling. They had an exact location on the sound but something wasn't quite right. They could see that there was not a rabbit or a coyote on that hillside. Who knows, they may have been called before too.
In the snow situation in rougher break country, they appeared unable to distinguish the distance. In the bare side hill situation, they appeared to have the ability to distinguish distance so what was the difference?
My opinion is that they could see something on the hillside that was out of place. In a white on white situation, they saw nothing. Think hard about that. That's why I believe camo has applications and in some situations you want them to see something.
Now if you throw an unnatural fake sounding "wabbit scweam" into the mix, you created another variable or a coyote howl that sounds like anything but a coyote howl.
If this coyote happened to hear your vehicle or saw you approach the stand, or smelled something they didn't like, you created more variables.
That's why these discussions on coyote behavior are so difficult to analyze without actually being there to sort through the many variables.
FALSE CONCLUSIONS!
Seldom do I see a coyote hangup when I am calling from a hillside that has enough brush, soapweeds, etc. to hide a coyote or rabbit. In that MORE NATURAL situation, they keep coming.
Next observation, sound does not carry the same in every situation. You have echoing, you have heavy dense air, you have clear air, you have obstructions (trees, brush and rolling hills), ALL AFFECTING SOUND making volume a moot point to distance IN MANY SITUATIONS. Volume simply reaches more coyotes.
I do agree that volume OF CERTAIN SOUNDS, is not a detriment. If you blast out an AUTHENTIC SOUNDING old dog coyote howl in close range of a batch of pups that recently had their ass kicked, volume would not be conducive to your calling success.
Previous experiences to certain sounds, another variable!
Under normal conditions (flatline, clear air, few obstructions) a coyote will hear your howl and respond much further than you can hear their response.
As a general rule of thumb with howling, if a coyote is close they USUALLY come in. If a coyote is midrange, they USUALLY answer and come in. If a coyote is a mile or more away, they USUALLY answer and keep answering and probably won't come in. You have to move on them.
I can asssure you that a coyote howling in a canyon is a lot harder to pinpoint than a coyote howling on the ridge. Now add some brush and dense air between you and the coyote and tell me that a coyote can pin point the sound in that situation. NO WAY IN HELL!
That flies in the face of the research that shows that a coyote can detect the origin of a sound within 30 feet at a half mile. Which I tend to believe, UNDER IDEAL STRAIGHTLINE CONDITIONS WITH FEW OBSTRUCTIONS.
Yes, a coyote has a much more accute sense of hearing than we do but the principles of what we hear apply to them as well.
One day at an ADC meeting with a bunch of trappers in the room, one fella brought a pet coyote pup along. We were all sitting around the room as this pup was chewing on a piece of rawhide on the bed. One guy at a time would start making lip squeaks and the pups ears would move in the direction of the sound while he continued to chew on the rawhide.
RADAR? LOL! Almost!
How many of you have watched a coyote mousing in snow? They hear these mice under the snow and the tilt their head to pinpoint the exact sound. POUNCE POUNCE, the nose dives into the snow and out comes a mouse in the jaws of a coyote.
You and I can walk across the snow all day and never hear a mouse under the snow unless he rattles in some leaves.
Here's another observation for you to think about. A friend of mine was watching coyotes feed on a carcass. One of the coyotes tipped his head back and howled and was answered by a pair of coyotes way off in the distance. After quite a long period of time, here came a pair of coyotes to join the feed. My friend backtracked these coyotes about 6 miles to where they changed their direction and came to the carcass in a straight line. Sound was really carrying with very few obstructions in that situation.
So what does all this mean?
Coyotes have great hearing but variables can and do affect what they hear and their ability to pinpoint the origin of the sound.
I have the luxury, from a coyote observation standpoint, of calling open country where I can see so much more behavior than you can in heavy cover.
I see how far coyotes respond, I see how far they come before they need to be reassured of the direction of the sound.
Many times I have called one time at a pair of coyotes at about 1/2 to 3/4 mile range and watched as they came all the way to within a 100 yards before stopping to look.
Like Wolverine said, it's a lot of theorizing. We know what we see but we theorize as to why.
I have been at this enough to know that the very next coyote could make a liar out of me.
My theories on this thread are backed with observations that have been discussed with others in this game and we simply are not led to any other conclusions.
As far as that lengthy thesis on sound, sorry but I quit reading that after the first couple paragraphs. I just don't see where it applies when you consider the sound limiting variables I mentioned of echos, brush, and dense air.
Hell anyone that has done any amount of calling knows that sound is variable just listen to the jets flying over and cows bellaring. Watch the observations of cattle and deer to your sounds and see what they hear.
As far as the horizontal plane theory?
Ahhhhhh.....ok? LOL!
~SH~
[ December 26, 2004, 08:07 AM: Message edited by: Wiley E ]
Posted by Leonard (Member # 2) on December 26, 2004, 10:10 AM:
Sort of like Bill's studio quality sound, eh? That's what I thought. Under laboratory conditions, sure, coyotes and humans might hear on a horizontal plane; but so what?
Nice to hear from you, Scott. Thanks for your thoughts.
Good hunting. LB
Posted by Bud/OR (Member # 450) on December 26, 2004, 02:02 PM:
Hey Guys,
I read all three pages, some posts more than once. It got way too scientific for a poor old boy that just likes to whack 'em and stack 'em. But, I do have a humble opinion.
I nearly always start with howls, loud and long. Then I turn on the e-caller and give them a rabbit, fawn or what ever, also loud. Next I do a couple series of pup growl/yelps, as loud as I can, with a Yote-Buster, while the tape is still playing loud. At that point I'm pretty much done with making any sound or movement from where I'm hiding.
I don't think doodley squat about vertical or horizontal audio planes. I've...brainwashed (boy, that's hanging it out there) myself that when I commence calling there WILL be a coyote coming. I always presume the coyote will know precisely where the sounds are coming from. I have found, over the years, that when I can see them they can see me. They can see my head turning, hands working the call, any descrepancies in my camo(wrong shade/color. Their ears have told their eyes to look in the correct direction. I don't even want to think about whether they have missed the mark by two or three degrees.
I like to have them keying on a decoy that is squalling and twitching, 75 or so yards from me. I am sure in my heart that if they have a clear visual of it at a quarter mile and I am quiet I have a chance to remain undetected in my hidey-hole.
On the other hand, If I am doing mouth calls only, these boys are coming right down my throat(albeit, five degrees off), from a long way out. I don't like the odds. This is why I use an e-caller. Granted, I may need to lip squeek to get them un-stuck or bark to stop them for a shot but I can do that with virtually no movement.
Bottom line is; I need to believe they can home in on prey sounds like they're pulled in on a string. I'm sure this mindset helps me get more gimme shots.
By the way, Mr Craig, I popped my first predator, a grey fox, about two hundred yards from the mill-works at Jerome in 1959. Used a Burnham call. He nearly climbed my leg(the fox, not Murray or Winston)...bullets just a flying. If you were there then you may have heard the gunfire.
I hope everyone gets to take next week off to hunt, like I do.
Bud
[ December 26, 2004, 02:10 PM: Message edited by: Bud/OR ]
Posted by Steve Craig (Member # 12) on December 27, 2004, 03:45 PM:
Bud,
I have called coyotes right down main street in Jerome! Was after a lion awhile back that was seen all over town,by everyone but me! Go figure. A lion was seen just the other day sitting next to a grade school in Cottonwood watching the kids play. Wonder what he wanted?!! This is the second time that has happened at that school. A friend of mine from Sedona called me the other morning and said a lion was drinking out of his swimming pool. Nobody has a camera when they need it. I have video footage of 7 grey fox and 2 javelina coming into the WT caller just south of Jerome. Bet you were using a WF4 to call that grey too! hehe
Steve
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