I believe bulls on the west side tend to get educated quickly by the archery guys and others driving around trying to locate prior to the start of early muzzy season. But, I believe you can get into the nasty holes and still manage a response from time to time. And, if you can draw a special permit into some of the more remote hunts, bulls will bugle into the middle of October. My son had the Whittier tag 6 years ago and we got responses each morning. I had the Mudflow tag last year and bugled bulls nearly all day long. That tag starts a week earlier than the Whittier. Less pressure = more vocal bulls. Having said all this, I believe the biggest bulls leave their cows prior to the start of early muzzy. Some cows, especially the year-and-half old ones, come into estrus beyond the normal range of dates.