A funnel is a natural or manmade object that persuades deer to travel the same place most of the time. Like between a pond and road, or finger of woods between swamps, etc. It could be a few strands of barb wire fence that has been knocked down between two posts when all the rest are strung tight. Even though deer can jump it, they mosy around through the easiest pass. My favorites is subdivisions being built near town! I'd try hunting them downwind near the narrowest location.