Wildlife experts have doubts about deer whistles

Web posted December 3, 1996

By Rosa Salter
The Allentown (Pa.) Morning Call

That stunned, deer-in-the-headlights look. A few, fleeting moments of panic. The squealing of brakes. A sickening thud, followed by the cracking of glass and the crumpling of metal.

Then, the huge repair bill.

Few motorists who have hit a deer ever forget it. Even fewer want to repeat the experience.

Wouldn't it be great if, for less than a 10-spot, you could prevent a deer from running in front of your car in the first place?

Well, you can, at least according to the promises made by makers of ``animal warning devices,'' commonly called ``deer whistles.''

The bullet-shaped cartridges mount on a vehicle's bumper or grille and emit sound waves that are supposed to alert deer.

As housing and business/industry sprawl spreads deeper into suburban and rural areas, deer and people come into ever-closer proximity. So promises of an effective deer repellent have become especially alluring.

Managers of several auto parts stores said deer whistles are selling briskly, especially now during the fall mating season, when deer accidents typically peak.

``For the cost, it's pretty good insurance,'' said Thomas Steinhagen, vice president of marketing for Cobbs Manufacturing Co. in Des Moines, Iowa, which has sold millions of its $7.99 ``Deer Warning'' devices in the past decade.

Dr. Steinhagen said Cobbs whistles emit two different ultrasonic frequencies, which are trade secrets. One creates a sound that can be heard at 100 yards and the other heard at 300 yards.

But do the deer whistles live up to their claims?

Not according to many wildlife biologists.

``People who have them swear by them, but scientifically I've never seen any proof that they work,'' said Dr. Margaret Brittingham, a wildlife ecologist at Pennsylvania State University in State College.

Brett Wallingford, Pennsylvania Game Commission wildlife biologist, said he had deer whistles on his vehicle for a few years. But he gave them up when he noticed that the deer he passed seemed unaffected.

``I never recall seeing deer flee as if something was hurting their ears,'' Mr. Wallingford said.

Mr. Wallingford said few scientific studies on the devices exist, and those have shown the whistles either don't produce any noise or don't affect deer's behavior.

One study, by the Georgia Game and Fish Department and reported in the November 1989 issue of Deer and Deer Hunting magazine, found that the force of air through the whistles was too weak to produce a noise at typical driving speeds of 25 to 55 mph.

Then, when researchers blew the whistles near captive deer, the deer didn't respond. The results bolstered a study by the University of Georgia showing that deer do not hear ultrasonic noise, the article said.

A second study, at the University of Wisconsin, also found that deer weren't fazed by the whistles. In that study, when a researcher tested the devices near seven species of the deer family, he got only one response from a bull elk, who not only didn't flee, but rather charged his enclosure, bugling loudly and breaking a post.

According to an article in the summer 1992 issue of Oregon's Wildlife Resources magazine, deer whistles are being sold in the United States based on claims from 20-year-old European studies. But those studies did not distinguish the effect of the noise of the oncoming vehicle from the effect of the devices.

And when state police in Ohio installed the whistles on patrol cars, deer accidents actually increased, the article notes, adding that the reason is unclear.

``My feeling is that people would develop a false sense of security and go tearing through rural Pennsylvania or Wisconsin or wherever as if there weren't any deer there,'' said Dr. Scott Craven, wildlife biologist at the University of Wisconsin.

However, Dr. Steinhagen stands by his company's product, attributing problems with the whistles in general to inferior, imported products.

``Ours work. There have been a lot of competing products that don't,'' he said. ``We consistently have ours tested for frequency and decibel output. We find many of the competitors' products fail or they fail to put out the frequency they claim.''

However, the company has not done ``empirical'' testing to see whether deer can hear the whistles or how they react, Dr. Steinhagen said.

He added that the idea that the noises will scare deer away is a misconception.

``It's like with a dog whistle - the dog will hear something and it stops to listen. It (the whistle) will alert the deer. Hopefully, it will prevent them from running across the road or cause them to run away,'' Dr. Steinhagen said.

Cobbs' product recently was redesigned to work at today's above-55-mph highway speeds, Dr. Steinhagen said.

He noted that the whistles will not work if they are not kept clean or if they are mounted incorrectly.

As further proof that the devices are effective, Dr. Steinhagen noted that some insurance companies waive a policy's deductible if a car with whistles is involved in a deer accident.

Both the Iowa and Connecticut State Police have mounted the devices on patrol cars with good results, with the latter reducing deer accidents by more than half, he said.

In Pennsylvania, however, neither state police nor game commission vehicles are equipped with the whistles, according to Wallingford.

He noted that although chemical pest deterrents must be proved effective before being sold, deer whistles need not meet such a test because they are considered mechanical products.

Wallingford added that even if the whistles do startle the deer, there's no guarantee that the animals won't crash into an oncoming car.

``Deer that get startled can do practically anything,'' he said. ``They can go forward (into a car) as easy as turn around and go back.''

He said the main benefit from the whistles may be that motorists who take the trouble to purchase and mount them may become more alert to the possibility of roadside deer.