They can hear me coming quite a ways off.
Much farther than most seem to think, too!
I know your deer are somewhat "conditioned" to your ATV sounds, and not badly spooked, but deer are generally more "alert" to anything out of their daily ordinary than most hunters seem to think.
It's not just their keen sense of smell either!
They a have a very keen ability to
distinguish sounds,
as well as very keen ability to pick up on certain movements from great distances.
Many hunters seem to totally overlook deer's abilities to "hear" parking vehicles, the click of door, a human walking, etc. Also, a real cold morning hunt killer: The metallic "pop" of a metal ladder stand.
Sometimes it seems many hunters are so focused on scent control,
they totally overlook sight & sound.