I often ask myself questions (What! Don’t you ask yourself questions?) Once I answer myself (yup I do that too,) I search for more answers. So I’m doing a Yay or Nay bit once in a while. Feel free to throw in your questions or answers. It’ll be even more interesting that way.
Deer Whistles and their effectiveness have been on my mind since it is the time of year they roam even more freely. Working odd hours, there are few nights I come home that I DON’T see deer either on the road or near my house. Many people I know have hit or been hit by deer. (I can’t explain the “been hit by” part—ask my sister about that, lol)
Q. How do I know it works?
A. Watch for animal reactions.
Uh, if I’m seeing the animal (or animals) reaction, shouldn’t I be able to stop in time to avoid it and, therefore, wouldn’t need the whistle?
I’m just asking, not making any judgment here.
Next, found a video at YouTube (there are many more over there) that suggest, for various reasons, the whistle doesn’t work.
Finally, comments I read at THE STRAIGHT DOPE had some of the best answers. One in particular stuck with me: “My father swore by the things for years, until one of the whistles was broken off by hitting a deer.” (Typoink 2009)
Drive safely, it's probably your best defense.