Weekend Garage Q & A: Bumper-mounted deer whistles

Q:Hitting a deer is a constant risk driving to and from the Twin Cities to our cabin in western Wisconsin. Some vehicles we see have bumper-mounted deer whistles. Do they really work? -Kristen S., Richfield

A:First of all, there are several manufacturers and they come in both mechanical (sound generated by airflow) and electronic styles.

The basic principle behind the invention is sound. Deer are flight animals. When danger approaches, they have two responses. One is to go still, motionless, hoping that whatever perceived predator has come within the area will not see them. The other is to run. Because running gives away their presence, stillness is preferable until the deer is convinced it's not going to work.

The design theory is to trigger the stillness response with a high pitched sound. If the deer was walking toward the road and into the path of your speeding automobile, the whistle is designed to put the deer on alert and cause it to stop moving so that the deer-car meet-and-greet never goes down. The deer stays still, you pass by, mammals of two and four legs live to see another day.

I called Save-a-Deer whistle company in Colorado to ask a few questions. Mike Livingston said his father bought their product, a one-piece two-tone mechanic whistle, from a wildlife agent in 1987. Since then, he estimates they have sold between 4 and 5 million of them worldwide to private vehicle owners, trucking companies and delivery companies like UPS.

He said they just sold a batch to South Africa, which conducted its own research on their efficacy. They concluded that they were effective for a variety of wildlife, not just deer, but were not effective on domesticated animals. Save-a-Deer's website also has test and review data from entities including a wildlife-dense area of California. These tests were positive.

Livingston's family uses them and he gives them to his friends in the mountains, too, and he says no one has reported any problems. His friends say the deer either stop or run away.

It's possible that the product is such cheap insurance, people buy it disproportionately to its actual value, but Livingston's sales and customer feedback cut against that theory. If the device were snake oil, e.g., trucking companies who bought them were hitting deer at their pre-whistle rates, you would expect word to get out and sales to drop off. The Save-a-Deer whistle is about six dollars; if you bought it and were unhappy, you're out less than two gallons of gas.

A word about swerving

Winter-summer temperature swings have beat up our roads again, causing a lot of potholes. A common reaction is for drivers simply to swerve around them. Often, they do this without looking--either giving no thought to drivers in adjacent lanes or relying on them to read the danger and anticipate the lane-change. That's pretty optimistic!