These elk get called to by every yayhoo with a bugle. I have seen trucks stop in front of our house and call at the elk in the pasture. Now, even if a rig stops, the elk run for the timber. Too much pressure before and during season can make them shut up during the day and do their bugling at night. I have seen guys bugle at quiet bulls and sent them running for cover. The heat does not help things. A nice, cool, foggy morning or a overcast day seems to be best. A storm will make them clam up as well.