It's likely because of lack of ideal bedding cover, and too much pressure. They weren't as predictable at my place until we created the cover and stopped pushing them all over........you really need sanctuary if you want them to be predictable. Find a nice south facing hillside, drop some trees in it to create browse and cover, and then leave it alone.............draw a line between that hillside and whatever the primary food sources are and look for pinchpoints along the way to setup on (or create some) and now you will see some VERY predictable movement.