Curious, did your 6,800' buck have something to keep him there like a ag field or something, or was it all native type country? I can see the exception to deer going high if they are using a alfalfa field or something to hold them.
I have read some bucks are hard wired and will return to the same area of high country each year and have found a study in WY's Lincoln county where the radio collard deer would return to the came summer grounds, not all of them but a large percentage. Shows how far they migrated as well.
This is the kind of research I can dig my teeth into...check it out.