I'm not sure that smell is the most important. I do feel it becomes less important each year unless you are hunting deep woods. If I had to pick one sense it would be sight combined with hunter movement.

Each year, where most of us hunt, deer become more accustomed to man. The smell of man is common. The sound of man is common. The sight of man is common. The movement of man, when he becomes a predator, is not common.

A man driving a tractor does not bother deer a bit. But let the man climb off that tractor and you have a different story.

Now deep woods deer is a different story. You see you just can't lump deer into a general category. You have to consider all the factors.

I have been studying deer for half a century and I don't know jack about them. I never thought I'd see the day they climbed on my patio and licked my grill.