Button Buck Biology

You could feel the tension in the air as the truck approached. Word had spread that Billy had mistakenly harvested a second buck fawn for the season and disappointed club members were gathered in anticipation of his arrival back at camp. Just one month earlier at the pre-season hunting 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 in the future. But, is this theory based in Whitetail Science?

And the Research Says?

A recent 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. A couple 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 and Why do Young Bucks Leave?

Multiple studies have revealed that approximately one-third of bucks disperse in early summer when they are 12 months old and two-thirds disperse during fall when they are 18 months old. These periods correspond to fawning and breeding. Importantly, the most common month for dispersal is October, which coincides 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 in October 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 buck will disperse.

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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 males. 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 – within a deer herd.

Implications for Hunting and Management

The results of these studies have significant implications for QDM programs, especially those on small properties. Since the average dispersal distance was 1-4 miles, even properties 3,000 acres and larger are potentially losing the majority of the button bucks produced on their properties. This emphasizes the need for a neighborhood approach to buck protection.

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 or not 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.

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 with appropriate educational materials like the posters available from the Quality Deer Management Association. These posters contain tips and techniques for aging and judging deer in the field that will make any hunter more successful. So, the next time you or someone in your hunting party mistakenly harvests a button buck, be sure to share the latest Whitetail Science.

Brian Murphy is an avid hunter, wildlife biologist and CEO of the Quality Deer Management Association (www.QDMA.com). He has worked exclusively in deer research and management for 25 years during which he has presented more than 600 lectures and authored more than 125 popular and scientific articles, book chapters and other educational materials designed for deer hunters and managers.