Your question could take a book to answer but we will keep it short. For starters the bull of most BH dreams already has the cows and he will move them out before he will fight a brat. Then you have the fact that the cows choose their bull in most cases and will protect him as lookouts unless a bull of VISIBLY equal attributes(size) is present. Thats why busting his cows and waiting for him to come see what the hell did it works for so many hunters. Elk become desensitized
to calls very easy. This is because they are exposed to it by every guy who has a call. The trick to a higher success rate in your hunting is to find an area that has few or no other hunters. Thats a primary reason for most pack-in trips. There is a way to get a little more lucky in the last part of a season. This is when a mature herd
bull looses enough weight and tires enough to be beaten by a rival. There is nothing less cautious than such an animal as he will then fight anything
that sounds like another bull and come in very quickly. Most newer hunters are then convinced they are expert callers and have found the secret formula for success. I have chased these critters for almost 40 seasons with stick&string and thats how I see it anyway. Wish you the best of hunting and make it a passion. You won't be disappointed.