generally around here it is November, with mid month being the height and the last few strays being picked up first couple weeks in dec. there have been some years though where it was even earlier ,with mid nov being pretty much the tail end. I think several things factor in to trigger it . weather , frost on the pumpkin,pressure ,when the moon hits their eye like a big pizza pie.............Its interesting; observing/learning the timing of it all in different places. It was my 1st time hunting on the west slope of the central Bighorns/Basin this yr; but during the 1st week of Nov, the muley bucks seemed noticeably goofy; many were rounding up does; and some had what looked like little harems, similar to elk rut behavior. Prob why the muley buck season was closed by then. We were hunting with doe tags.