Lets put this way, the bugling gets intense around the 15th of Sept. But the rut starts in Aug. Around the 15th of Aug.the bulls shed velvet from their antlers and begin to brake up bachler groups and move tword breeding areas. The older cows will start estrus cycles around the 20th of Aug. If not bred, the cow will have cycles about every 28 days. Thats about Sept. 15th for the second cycle. By this point bulls and cows are together. I have had the fastest action before the bulls and cows are together. That is when the bulls are setting up their domain and start talking. But the temps are still warm and alot of the heavy activity is at night. And in Colorado, Sept. 10th will be the start of muzzle loader season. I would come before or after that.
Gselkhunter