My gut instinct tells me that terrain is the key to this question. If your on top of a hill, I'd guess they'd have to come in close because your scent will most likely be up in the air farther out. Also, most if not all wild game use terrain lines and habitat breaks to travel. For example, in an open field with a drainage ditch or swale, a coyote may very well use the swale to travel. If your in the woods on a mountain, they may use a logging road(which most likely was made on a "bench" of the hill. We call these avenues Travel corridors. If you've spent any amount of time watching animals in wooded areas you may have noticed that they frequently use the path of least resistance. Coyotes and fox, along with many other animals tend to use deer trails, and deer naturaly make their trails on terrain lines such as small and large benches on side hills, saddles going over mountains, and breaks or edges in the veggitation/forest. Coyotes love to break rules though, and like John-PA said, they could come charging right in from out of no where. This has happened to me a few years ago! I'm glad I had my shotgun in my hands on that hunt! My first coyote ever!