I've seen deer and elk feed alongside one another until one day the rut flips a switch and the deer bug out. Seems all is fine until the bulls start getting aggressive.
Other areas I've seen bucks actually get aroused by the cow estrus and keep bird dogging the herd. Bulls chase them off and they keep coming back. I'm not sure why some get bothered and others don't.
Never been able to find the answer.
I do know that some areas hold deer until sometime in August and then the deer can no longer sustain themselves on the feed available. Elk on the other hand can still strive on the vegetation that is left since they are cud chewing animals where deer are not. I expect the deer would move back in as soon as the vegetation became more compatible to their digestive/nutritional needs.
You could always drive up close to the elk in a big arse white truck, leave the engine running and start bugling from the drivers seat. That seems to scare every elk in our area across the boundary and into the Toutle a mile sometimes two. We'll have almost 100 elk in a draw opening day and after two days of the bungholes bugling from their trucks there is not a single elk to be found for weeks
