Jon,

Deer are very alert to smells and noises they associate with danger.  If they associate the noise of an ATV with danger, they will certainly avoid the area or at least be alerted by the presence of an ATV.  On the other hand, they may simply ignore the ATV if they don’t associate it with danger.  For example, deer at most golf courses don’t associate golf carts with danger.  They see them every day and are not harmed or threatened by them.  However, a pickup driving down a golf trail would probably cause the local deer herd to be on alert and limit their movement until they sensed the threat passed.

Growing Deer together,

Grant