Been up since Aug 29.
On morning of sep 1, cows/calves were still in summer groups, very large herds (for this area). Bulls were mixed in with summer herds with lots of cow/calf talk and bulls bugling, raking, grunting, panting, glunking. You'd have thought it was peak rut. Literally hundreds of cows calves spread across about 5 square miles with 7-8 different bulls talking and lots of rags not talking.
Sep 2, summer herds broken into smaller herds (not "rut sized" herds but smaller), some bugling morning and evening but not consistent.
Sep 3, nearly all large herds broken up. Seeing groups of <10 cows/calves and solo bulls. Handful of bugles in the morning
Sep 4, two bugles around 5:30am. Small groups of cows, <6, spotted around. Bulls coming in silently to calls.
TLDR: the "august summer herd breakup" happened late in my area and made some super cool opening day activity. Typical pre-rut now with limited bugling.