Whatever the harvest in your hunting area in 2020, this research on button bucks can help you formulate a smart management plan for 2021.
You could feel the tension in the air as the truck approached. Word had spread that Billy had mistakenly harvested his second buck fawn for the season, and disappointed club members were gathered in anticipation of his arrival back at camp. Just two months earlier at the pre-season hunting camp meeting, members were encouraged to harvest does—but cautioned against harvesting buck fawns or “button bucks.” The club even instituted a $100 fine for the first button buck and a $250 fine for the second, to drive this point home. Their strategy seemed logical—to protect as many button bucks as possible, so they will remain on the property and become older and larger bucks in the future. But, is this theory based in Whitetail Science?
And The Research Says? A study by Dr. Mark Conner and others in Maryland provided some interesting findings regarding movements of young bucks. During this study, they captured and radio-collared 75 male white-tailed deer ranging from six to 18 months of age, and followed 51 of them until death or the end of the study. Of these, 70 percent dispersed from the 3,300-acre study area, with half dispersing more than 3.7 miles. Dispersal distance varied greatly from 1.2 to 36 miles. Amazingly, two of these youngsters even swam a mile-wide river during dispersal!
A similar study conducted by Dr. Harry Jacobson in Mississippi reported that 42 percent of the 52 male whitetails captured as fawns, died more than three miles from their original capture site. Interestingly, Jacobson found that once the young bucks dispersed, they generally remained within their new home range until death.
When & Why Do Young Bucks Leave? Multiple studies have revealed that half or more of all young bucks will disperse from their birth areas. Of those that do disperse, approximately one-third do so in early summer, when they are 12 months old, and two-thirds do so during fall when they are 18 months old. These periods correspond to fawning and breeding. Importantly, the most-common months for dispersal are October and November, which coincide with many hunting seasons. It also helps explain why many yearling bucks appear “clueless,” and are harvested in such high numbers. It is possible that a yearling buck you encounter during October or November is on your property for the very first time.
While the timing of dispersal is fairly well documented, its causes are less understood. To date, two potential dispersal causes have been discovered—maternal aggression, and competition among yearling bucks for social rank.
A study conducted by Stefan Holzenbein and Dr. R. Larry Marchinton in Georgia compared 34 buck fawns divided into two groups—19 that were left with their mothers (non-orphans), and 15 whose mothers were harvested or removed (orphans). The results were surprising. By 30 months of age, 87 percent of the non-orphans had dispersed from their birth areas, but only nine percent of the orphans had left theirs. In other words, dispersal was greatly reduced if the young buck’s mother was removed prior to dispersal. So, harvesting a doe with a button buck at her side may significantly decrease the odds the young buck will disperse. In other words, selective doe harvest can help you “bank” extra bucks for future years.
Head size, shape and length are important characteristics when separating adult does from fawns. The adult doe’s head (above right) will be longer and sleeker than that of a fawn.
The second potential dispersal cause—a yearling buck’s social rank—was discovered in the Conner study mentioned previously. They found that dispersers were more likely to associate with other yearling bucks—and participate in breeding season behaviors—than were non-dispersers. They concluded that sexual competition among yearling bucks was a potential cause of dispersal.
Most deer researchers agree that dispersal coincides with changes in a young buck’s social position within the herd. Young bucks are social outcasts recently expelled from their own family group, and excluded from joining other family groups or associating with older bucks. Often, the only members of the herd that will “befriend” them are other yearling bucks, buck fawns and occasionally, yearling does. Therefore, the actual dispersal “trigger” is likely a complex interaction of social pressures—by both bucks and does.
Implications For Hunting & Management. The results of these studies have significant implications for deer management programs, especially on small properties. Since the average dispersal distance is 1-4 miles, even properties 3,000 acres and larger are likely losing the majority of the button bucks produced on their properties. This emphasizes the need for a “neighborhood approach” to buck protection. Keep in mind that dispersal is occurring across a vast landscape. While you are sending some of your bucks to your neighbors, they are doing likewise. You are receiving young bucks from at least a few miles away, in several directions. The better your habitat and more balanced your deer herd from a density perspective, the more of these young bucks that are likely to set up shop on your land.
An adult doe’s body (above right) will be rectangular in shape compared to a fawn’s, which will be square.
The best way to minimize button buck harvest is to have educated, experienced hunters who can make accurate harvest decisions in the field. While this level of experience can take years, it also can be learned reasonably quickly. The first step is to separate does from fawns, which can be done by paying close attention to body and head characteristics, as well as behavior. A mature doe will have a rectangular-shaped body, while a fawn’s will be square. A doe’s head will be long and sleek with ears that seem proportional in size. A fawn’s head will be short, with ears that appear too large. An adult doe will typically lead her fawns to and from food and cover—and she will be much more cautious while doing so. Fawns will often seem oblivious to their surroundings, and sometimes exhibit “playful” behaviors.
When distinguishing between buck and doe fawns, look for a flatter head and the presence of “buttons” or small raised bumps on buck fawns (above left). Doe fawns will have smooth, rounded heads.
Once you have identified a fawn, the next step is determining if it’s a doe fawn or buck fawn. The primary distinguishing feature is a flatter head and the presence of “buttons” (small pedicles) on buck fawns. A doe fawn’s head will be round and smooth. Buck fawns are also bolder, often being the first to enter a food plot or other food source. A good friend once remarked that, “Eleven times out of 10, the first antlerless deer on a food plot will be a button buck!” This is a good reminder of the importance of waiting for a size comparison to separate adult does from fawns. Keep this in mind when deciding whether to harvest a lone antlerless deer.
Now, back to Billy. Should club members fine Billy for harvesting the button buck and possibly even expel him from the club? Not necessarily. Billy has demonstrated a willingness to harvest antlerless deer, which is commendable. In most cases, harvesting the correct number of deer on a property is more important than whether a few button bucks are mistakenly taken in the process.
Should the club continue to protect button bucks? Absolutely! Not all young bucks disperse, and even those that do will help improve surrounding deer herds. Therefore, if any penalties are imposed, they should be sufficient to encourage hunters to look carefully before making harvest decisions, but not so severe they refrain from harvest altogether, or do not report their “mistakes.” In general, as long as button bucks represent 10 percent or less of the antlerless harvest, little, if any, negative impact to a management program will occur. So, the next time you or someone in your hunting party mistakenly harvests a button buck, be sure to share the latest Whitetail Science on button buck biology.
