Rauly,
I can tell you that I have heard them and thought they were right on top of me and found that they were actually a couple hundred yards off.
I've heard them and thought well I better close in and bump them out of a ditch 50 yards away.
I think which way they are facing also comes into play.
Looks like my answer is just as perfectly vague as the rest.
Help Any?

[img]graemlins/dork.gif[/img] [img]graemlins/stupid.gif[/img]
GRB