It was once thought that large, mature bucks dominated the breeding in deer herds. The premise was that the largest individuals would successfully defended all receptive does (does that are in estrous) from other bucks in the area. Of course, genetic testing came along and that allowed researchers to identify what exactly is happening out there in the woods. During the breeding season whitetail bucks search for individually receptive does. And understand this, it is not uncommon for a buck to court a doe for up to a day prior to her being receptive and then breed her repeatedly over the 24 to 36 hours (while she is in estrous).
The buck then searches for another doe and repeats the process. Therefore, bucks that successfully breed may spend as much as 24 to 48 hours with a single doe before looking for another. Due to the time spent with an individual doe, and because the most does in a balanced population are bred over a relatively short time frame, a single buck just can not monopolize the breeding.
In a Texas study, the most prolific buck sired six fawns in a single year. In another study, successful bucks averaged less than three fawns per year over an 11-year period. Similar research in Michigan found that 17 bucks sired 67 fawns for an average of 3.9 fawns per buck. Individual bucks sired anywhere from one to nine fawns in her study, so everybody is in the game.This just shows that “dominant” bucks don’t monopolize the breeding. And this may surprise you, but bucks don’t even sire all of the fawns from each doe they breed. One study revealed multiple paternity occurred in about 24 percent of compound litters (twins and triplets). Approximately one in four sets of twins or triplets had two fathers! This further shows that does are breeding with multiple bucks, which further clarifies that individual whitetail bucks do not monopolize breeding.
This makes proper culling of your buck herd that much more important. In addition, in deer population with balanced sex ratios it also ensures most does are bred during their first estrous cycle, which subsequently means fawns will be born during optimal fawning dates the following spring.
The important thing to remember is that young bucks do in fact participate in some of the breeding, but mature bucks do most of it in populations with good age structure. But then again, if you have more mature bucks, the you expect them to do more of the breeding. Past research showed bucks 3½ years of age and older sired 70 and 85 percent of fawns, respectively, in populations with reasonable age structure and sex ratios.