Cut and paste from:
http://www.ibmwr.org/prodreview/deerwsle.html
"Whistles and Whitetails"
By: Randall P. Schwalbach
DEER AND DEER HUNTING, November 1989
Recently, several wildlife researchers questioned the validity of these claims [manufacturer claims that deer whistles work]. A need to physically test deer whistles and explore the absence of ultrasonic sound arose from the absence of scientific literature coupled with the general unwillingness of companies that market deer whistles to provide any meaningful data supporting their claims. Working independently and using different methods, researchers in both Georgia and Wisconsin arrived at similar conclusions.
These findings identify factors that indicate considerable doubt concerning the effectiveness of these whistles as deterrents to car/deer collisions:
1) Some deer whistles do not emit the ultrasonic sound under the advertised operating conditions [typically when the vehicle exceeds 30 mph].
2) The physical properties of ultrasonic sound negate its effectiveness at distances required to warn deer.
3) We know little about the auditory limits of deer, but what we do know indicates that deer hear approximately the same frequencies as humans.
4) If deer could hear ultrasound, we do not know that it would alarm them or induce a flight response.
The Georgia Game and Fish Department began their investigation by requesting data from the "scientific tests" the advertisers had used to support their product claims. In response, one distributor sent a packet of newspaper clippings and letters from sheriffs [sic] departments, all attesting the whistles were a godsend. One deputy had tested them by driving his whistle-equipped patrol car toward a herd of deer in a field. The deer scattered, he reported with enthusiasm. Such testimonials - of no scientific significance - prompted responsible evaluation.
The [Georgia Game and Fish] department recognized that rigorous investigation of the whistles' effect on animals was dependent on the whistles making the sound in the first place.... Using a Custom Telemetry Ultrasonic Receiver [plus more measuring equip], they did not detect any ultrasonic sounds [at speeds from 25-55mph]. According to Greg Schidwachter, "Apparently, the force of air through the device was too weak to produce sound of any frequency."
[Even if the device DID make the sound claimed at frequencies from 16 to 20 kHz] We found no published research indicating that frequencies from 16 to 20 kHz elicit a flight response in deer or other ungulates, such as cows and horses.
A study of the hearing ability of white-tailed deer at the University of Georgia sheds additional light. Unpublished results by Stattleman indicate that deer cannot hear sounds with frequencies of 6 to 20 kHz. In this respect, white-tailed deer hear approximately the same frequencies as humans.
To complete the study, the Georgia Game and Fish personnel blew the whistles by mouth near some captive deer. This did not affect their behavior in any way. The team concluded, "The whistle we tested does not emit an ultrasonic sound under the advertised conditions, and deer could not hear it, if it did."
Timothy J. Lawhern, an undergraduate student at the University of Wisconsin, Madison, arrived at similar conclusions through a separate and perhaps more rigorous investigation of deer whistles. In contrast to the Georgia study, Lawhern found the three devices he tested to produce ultrasonic frequencies up to 48 kHz; however, he still concluded that "it is highly unlikely deer would be capable of responding to this signal."
Interestingly, in the course of his research Lawhern tested the whistles in the presence of seven species of the deer family, including 45 white-tailed deer. Possible responses he looked for included ears or head turning, flinching, or looking in the direction of the sound. Out of all these animals, however, only one response was noted, this from a single bull elk. At the shrill sound of the lower pitched whistle (audible to human ears) he charged the enclosing fence, in the process breaking a 2X4 post. In prolonged rage, he then bugled and urinated.
[After testing for the frequencies which the devices produce] Lawhern concluded that "they do indeed produce ultrasonic frequencies." But as the Georgia study indicated, so did Lawhern discover that not all sounds produced fell within the range of ultrasound."
Lawhern summed it up: "Based on the knowledge of ultrasonic frequency coupled with observed field testing of various animal species, it is highly unlikely that an ultrasonic signal produced by the whistle devices would reach a deer at a decibel level such that it would be detected even at ten meters, much less than the 300 to 400 meters claimed."
Scott Craven, University of Wisconsin Extension Wildlife Specialist, agrees with Lawhern's conclusion. He believes that people who install whistles may be more likely to watch for deer. At the same time he explains, "Any cure is going to look attractive. Some people use the whistles and are happy with them because they haven't hit a deer."
Craven receives many requests for advice on the use of deer whistles and he concludes, "Until I see some solid evidence to support the use of deer whistles, I cannot, as a wildlife professional, recommend their use. I contend there is no substitute for driver education and awareness of the areas, seasons and times of day of vulnerability."
As expected, the number of car-deer collisions relates directly to the overall intensity of deer movement. Mid-Spring and mid-Fall (during the rut) require special attention. In mid-Spring, deer cross roads frequently as they try to graze on new herbaceous vegetation. . . . In northern states, the salt-drive phenomenon also causes deer to frequent roadsides as they search for residue from winter road-salting operations.
According to research in Michigan and Wisconsin, the rutting season in fall, with its increased deer movement represents a time of peak hazard. At this time deer are often oblivious to outside happenings as they pursue breeding activities. Through a chronology of 1,151 such collisions from 1976-78 in Columbia County, Wisconsin, Pils and Martin (1979) identified November as the peak month for car-deer collisions. . . . They also noted a surge late in November, which they attributed to the hunting season [and theorized that it was] probably because hunting disturbance caused greater deer movements.
Meanwhile, as deer remain primarily nocturnal at all seasons, night-time driving increases the chance of hitting a deer. Pils and Martin noted that most deer collisions occur at sunset.
In addition to seasonal peaks in deer movements across roads, deer cross some sections of road more frequently than others . . . . Motorists who do not honor [Deer Crossing] signs (by slowing down) or who simply do not notice these signs at all further increase their chances of hitting a deer.
[paraphrasing the summary]: If use of deer whistles results in increased awareness of deer dangers, then a motorist's chances of hitting a deer may be reduced. On the other hand, use of deer whistles may give him a false sense of security.
Cut and paste from:
http://advance.uconn.edu/2002/021118/02111812.htm
Deer-Whistles Ineffective,
Says Bioacoustics Researcher
By Janice Palmer
Slow down! Deer crossing. It's a warning to be heeded this time of year. Deer are on the move during late fall and early winter, either because it's hunting season or because they are seeking a mate.
On the highways and byways across North America, nearly 750,000 collisions occur each year between deer and vehicles. Efforts to reduce that number have spun off a multi-million-dollar industry: deer whistles.
Peter Scheifele, director of bioacoustics research at the National Undersea Research Center, conducted a scientific study of deer whistles.
Photo by Shannon McAvoy
Scheifele, an animal bioacoustics and audiology expert, wanted to know more about the devices, so he and his research team scientifically tested their effectiveness.
The small plastic whistles, easily attached to car bumpers, hit the marketplace several years ago. Some are sold for as little as five dollars. They vary in design, but their claims are relatively the same. Their manufacturers promote them as "acoustic attention-getters", alleging deer would react to the whistle by remaining still.
"There has been a lot of conjecture about whether the whistles work or don't work, and we are one of the first independent groups to scientifically test them," says Scheifele, director of bioacoustic research at the National Undersea Research Center at Avery Point and a researcher in the Department of Animal Science.
He and his team tested six air-fed whistles in the laboratory and in the field. The study's goal was to determine the actual frequencies generated by the whistles and the intensity at which they are produced, compare that data to the hearing abilities of deer, and then take the animal's acoustic behavior into consideration.
Following the directions on each package, the team mounted the devices onto a car's front bumper. Using a road closed to the public, they drove the car at speeds ranging from 30 to 45 miles per hour while recording sound and data.
"We tested them strictly from an acoustical point of view," explains Scheifele. He found that the whistles typically produce a signal either at a frequency of 3 kilohertz (kHz) or 12 kHz. Both, as it turns out, are problematic.
The hearing range of white-tailed deer, the most common species in the United States, is between 2 kHz and 6 kHz, so the animal is not capable of hearing the 12 kHz signal.
Although deer may be able to hear the 3 kHz signal, it is only 3 decibels louder than the road noise created by the car, so the signal is buried. Scheifele points out that the situation would be worse with additional traffic in the area or if the wind was blowing.
Since completing the study, a new electronic whistle has been put on the market. Although Scheifele has not had an opportunity to test it, he has examined its advertising claims. He says the specs for the electronic whistle are considerably different from those of the air-fed devices, so "there is a possibility that the electronic whistle is more effective than the air-fed devices."
But even if deer can hear the electronic signal, the UConn scientist questions how one alerts rather than startles the animal. This is where animal behavior comes into play.
"Think about the metaphor 'deer in the headlights'," says Scheifele. "It is used to conjure up an image of someone who is confused or frightened. When deer sense something unusual, we do not know for sure how they are going to react."
Will they freeze in their tracks, run off, or charge towards the sound? Their behavior is related to the "fight-or-flight response". According to scientific literature on the subject, there is an amount of space in which an animal feels safe, but once that boundary is violated, the animal's reaction is unpredictable. Its response will depend on a number of factors, including age, sex, type of enemy, and surroundings.
"All in all, the air-fed whistles do not make sense to me acoustically, " states Scheifele.
He has written a paper on his findings and submitted it to the Acoustical Society of America's Acoustics Research Letters Online where it will shortly be under review.
Cheers
ken
http://www.ibmwr.org/prodreview/deerwsle.html
"Whistles and Whitetails"
By: Randall P. Schwalbach
DEER AND DEER HUNTING, November 1989
Recently, several wildlife researchers questioned the validity of these claims [manufacturer claims that deer whistles work]. A need to physically test deer whistles and explore the absence of ultrasonic sound arose from the absence of scientific literature coupled with the general unwillingness of companies that market deer whistles to provide any meaningful data supporting their claims. Working independently and using different methods, researchers in both Georgia and Wisconsin arrived at similar conclusions.
These findings identify factors that indicate considerable doubt concerning the effectiveness of these whistles as deterrents to car/deer collisions:
1) Some deer whistles do not emit the ultrasonic sound under the advertised operating conditions [typically when the vehicle exceeds 30 mph].
2) The physical properties of ultrasonic sound negate its effectiveness at distances required to warn deer.
3) We know little about the auditory limits of deer, but what we do know indicates that deer hear approximately the same frequencies as humans.
4) If deer could hear ultrasound, we do not know that it would alarm them or induce a flight response.
The Georgia Game and Fish Department began their investigation by requesting data from the "scientific tests" the advertisers had used to support their product claims. In response, one distributor sent a packet of newspaper clippings and letters from sheriffs [sic] departments, all attesting the whistles were a godsend. One deputy had tested them by driving his whistle-equipped patrol car toward a herd of deer in a field. The deer scattered, he reported with enthusiasm. Such testimonials - of no scientific significance - prompted responsible evaluation.
The [Georgia Game and Fish] department recognized that rigorous investigation of the whistles' effect on animals was dependent on the whistles making the sound in the first place.... Using a Custom Telemetry Ultrasonic Receiver [plus more measuring equip], they did not detect any ultrasonic sounds [at speeds from 25-55mph]. According to Greg Schidwachter, "Apparently, the force of air through the device was too weak to produce sound of any frequency."
[Even if the device DID make the sound claimed at frequencies from 16 to 20 kHz] We found no published research indicating that frequencies from 16 to 20 kHz elicit a flight response in deer or other ungulates, such as cows and horses.
A study of the hearing ability of white-tailed deer at the University of Georgia sheds additional light. Unpublished results by Stattleman indicate that deer cannot hear sounds with frequencies of 6 to 20 kHz. In this respect, white-tailed deer hear approximately the same frequencies as humans.
To complete the study, the Georgia Game and Fish personnel blew the whistles by mouth near some captive deer. This did not affect their behavior in any way. The team concluded, "The whistle we tested does not emit an ultrasonic sound under the advertised conditions, and deer could not hear it, if it did."
Timothy J. Lawhern, an undergraduate student at the University of Wisconsin, Madison, arrived at similar conclusions through a separate and perhaps more rigorous investigation of deer whistles. In contrast to the Georgia study, Lawhern found the three devices he tested to produce ultrasonic frequencies up to 48 kHz; however, he still concluded that "it is highly unlikely deer would be capable of responding to this signal."
Interestingly, in the course of his research Lawhern tested the whistles in the presence of seven species of the deer family, including 45 white-tailed deer. Possible responses he looked for included ears or head turning, flinching, or looking in the direction of the sound. Out of all these animals, however, only one response was noted, this from a single bull elk. At the shrill sound of the lower pitched whistle (audible to human ears) he charged the enclosing fence, in the process breaking a 2X4 post. In prolonged rage, he then bugled and urinated.
[After testing for the frequencies which the devices produce] Lawhern concluded that "they do indeed produce ultrasonic frequencies." But as the Georgia study indicated, so did Lawhern discover that not all sounds produced fell within the range of ultrasound."
Lawhern summed it up: "Based on the knowledge of ultrasonic frequency coupled with observed field testing of various animal species, it is highly unlikely that an ultrasonic signal produced by the whistle devices would reach a deer at a decibel level such that it would be detected even at ten meters, much less than the 300 to 400 meters claimed."
Scott Craven, University of Wisconsin Extension Wildlife Specialist, agrees with Lawhern's conclusion. He believes that people who install whistles may be more likely to watch for deer. At the same time he explains, "Any cure is going to look attractive. Some people use the whistles and are happy with them because they haven't hit a deer."
Craven receives many requests for advice on the use of deer whistles and he concludes, "Until I see some solid evidence to support the use of deer whistles, I cannot, as a wildlife professional, recommend their use. I contend there is no substitute for driver education and awareness of the areas, seasons and times of day of vulnerability."
As expected, the number of car-deer collisions relates directly to the overall intensity of deer movement. Mid-Spring and mid-Fall (during the rut) require special attention. In mid-Spring, deer cross roads frequently as they try to graze on new herbaceous vegetation. . . . In northern states, the salt-drive phenomenon also causes deer to frequent roadsides as they search for residue from winter road-salting operations.
According to research in Michigan and Wisconsin, the rutting season in fall, with its increased deer movement represents a time of peak hazard. At this time deer are often oblivious to outside happenings as they pursue breeding activities. Through a chronology of 1,151 such collisions from 1976-78 in Columbia County, Wisconsin, Pils and Martin (1979) identified November as the peak month for car-deer collisions. . . . They also noted a surge late in November, which they attributed to the hunting season [and theorized that it was] probably because hunting disturbance caused greater deer movements.
Meanwhile, as deer remain primarily nocturnal at all seasons, night-time driving increases the chance of hitting a deer. Pils and Martin noted that most deer collisions occur at sunset.
In addition to seasonal peaks in deer movements across roads, deer cross some sections of road more frequently than others . . . . Motorists who do not honor [Deer Crossing] signs (by slowing down) or who simply do not notice these signs at all further increase their chances of hitting a deer.
[paraphrasing the summary]: If use of deer whistles results in increased awareness of deer dangers, then a motorist's chances of hitting a deer may be reduced. On the other hand, use of deer whistles may give him a false sense of security.
Cut and paste from:
http://advance.uconn.edu/2002/021118/02111812.htm
Deer-Whistles Ineffective,
Says Bioacoustics Researcher
By Janice Palmer
Slow down! Deer crossing. It's a warning to be heeded this time of year. Deer are on the move during late fall and early winter, either because it's hunting season or because they are seeking a mate.
On the highways and byways across North America, nearly 750,000 collisions occur each year between deer and vehicles. Efforts to reduce that number have spun off a multi-million-dollar industry: deer whistles.
Peter Scheifele, director of bioacoustics research at the National Undersea Research Center, conducted a scientific study of deer whistles.
Photo by Shannon McAvoy
Scheifele, an animal bioacoustics and audiology expert, wanted to know more about the devices, so he and his research team scientifically tested their effectiveness.
The small plastic whistles, easily attached to car bumpers, hit the marketplace several years ago. Some are sold for as little as five dollars. They vary in design, but their claims are relatively the same. Their manufacturers promote them as "acoustic attention-getters", alleging deer would react to the whistle by remaining still.
"There has been a lot of conjecture about whether the whistles work or don't work, and we are one of the first independent groups to scientifically test them," says Scheifele, director of bioacoustic research at the National Undersea Research Center at Avery Point and a researcher in the Department of Animal Science.
He and his team tested six air-fed whistles in the laboratory and in the field. The study's goal was to determine the actual frequencies generated by the whistles and the intensity at which they are produced, compare that data to the hearing abilities of deer, and then take the animal's acoustic behavior into consideration.
Following the directions on each package, the team mounted the devices onto a car's front bumper. Using a road closed to the public, they drove the car at speeds ranging from 30 to 45 miles per hour while recording sound and data.
"We tested them strictly from an acoustical point of view," explains Scheifele. He found that the whistles typically produce a signal either at a frequency of 3 kilohertz (kHz) or 12 kHz. Both, as it turns out, are problematic.
The hearing range of white-tailed deer, the most common species in the United States, is between 2 kHz and 6 kHz, so the animal is not capable of hearing the 12 kHz signal.
Although deer may be able to hear the 3 kHz signal, it is only 3 decibels louder than the road noise created by the car, so the signal is buried. Scheifele points out that the situation would be worse with additional traffic in the area or if the wind was blowing.
Since completing the study, a new electronic whistle has been put on the market. Although Scheifele has not had an opportunity to test it, he has examined its advertising claims. He says the specs for the electronic whistle are considerably different from those of the air-fed devices, so "there is a possibility that the electronic whistle is more effective than the air-fed devices."
But even if deer can hear the electronic signal, the UConn scientist questions how one alerts rather than startles the animal. This is where animal behavior comes into play.
"Think about the metaphor 'deer in the headlights'," says Scheifele. "It is used to conjure up an image of someone who is confused or frightened. When deer sense something unusual, we do not know for sure how they are going to react."
Will they freeze in their tracks, run off, or charge towards the sound? Their behavior is related to the "fight-or-flight response". According to scientific literature on the subject, there is an amount of space in which an animal feels safe, but once that boundary is violated, the animal's reaction is unpredictable. Its response will depend on a number of factors, including age, sex, type of enemy, and surroundings.
"All in all, the air-fed whistles do not make sense to me acoustically, " states Scheifele.
He has written a paper on his findings and submitted it to the Acoustical Society of America's Acoustics Research Letters Online where it will shortly be under review.
Cheers
ken
