Buckslayer,
Most of the thoughts and ideas above are good ones. However, the definition given for a funnel is a little misleading as I interpret it. A funnel is not the object that redirects deer, but rather the more narrow path taken by deer that have been redirected. A small but important difference.
Think of an hourglass and the small opening that separates the two bulbs on the top and bottom. That narrow opening is a good theoretical example of a funnel. Rather than hunt in a larger area where deer are free to spread out and thus avoid you, put yourself in the narrow area where the deer must concentrate to move between their favorite areas.
Funnels, as stated above, come in many forms, but the chief identifier is an area that has at least two opposing obstacles to deer movement that are separated by a narrower area that provides good cover or the shortest path between areas of good cover. Deer will naturally be "funneled" by the obstacles on both sides into the narrow area when they choose to travel past the obstacles.
Obstacles may be anything that might deter deer movement. Human dwellings or activity sites, open fields, major roads, precipitous terrain, impenetrable brush, high fences, and large bodies of water are a few that I have identified and used in the past. Funnels may be large (hundreds of yards wide) or very small (twenty or thirty yards wide), and have elements of terrain, vegetation, or both, that provide cover or minimal exposure. The ideal funnel is rather narrow and separates two very expansive and strong detriments to deer movement situated astride two very attractive and different high-use deer areas.
I wish you luck in your search for deer funnels. In my experience, they can be readily found in most deer habitat with a little ground research and a good aerial photograph. They are my most favored ambush points for whitetails, and sometimes the most productive ones are overlooked by other hunters.
