QUESTION: I would like to know if bucks leave their home area to prevent interbreeding, and if so at what age? Also, how far do they have to travel to get away from their own blood lines. -- A. J. Wies
ANSWER: I assume you mean "inbreeding." If so, the answer to the first part of your question is, sort of.
Yearling buck dispersal is a common phenomenon in whitetail populations. A buck fawn typically remains with his dam (mother) throughout the first six months of his life. During the peak of rut, when the doe is ready to breed, he will become separated from her. This is why you often see lone fawns, or what I call "rut orphans," during this period.
The adult doe and her young often regroup after the rut and may remain together throughout the winter. She will eventually drive her yearling offspring out of her core area the following spring, when she gives birth to new fawns. However, these yearlings might remain within her home range until fall.
Yearling bucks typically disperse from their natal home range - the area where they were born - sometime during their second fall. They usually travel more than two miles to establish a new home range. Most biologists agree this dispersal is caused by social pressures, but still aren't certain if it is caused by adult females harassing yearling bucks to avoid inbreeding, or by breeding competition among bucks.
Results from a study at the 3,300-acre Chesapeake Farms wildlife and agriculture demonstration area suggest that breeding competition among yearling bucks is the primary cause of dispersal. Regardless of why deer disperse, it ultimately reduces the chances of inbreeding.
The study also looked at what effect an older male age structure might have on breeding competition. They found that breeding behaviors, like sparring in yearling bucks, decreased after implementation of a quality deer management program that resulted in an older age structure.
As a result, yearling dispersal also declined.
It should be noted that another study found somewhat different results.
Researchers discovered that buck fawns orphaned during their first fall - usually when their mother was harvested - tended to have higher survival rates than non-orphans. The suspected this was because they remained in their natal home range - an area they were familiar with - as yearlings rather than dispersing to unfamiliar territory during the hunting season.