The Button Buck Dilemma
overall deer abundance and the future availability of adult bucks.
One way to evaluate the effects of hunting on deer numbers is by using a population model. A population model is a mathematical formula used to predict the growth or decline of a deer herd. The formula takes into account natural mortality, reproduction and hunter harvest. Our population model is based on research on Missouri deer.
Studies have shown that Missouri deer are very productive. Most mature does (at least 2 years old) produce twins, and 10 to 15 percent produce triplets. In our most productive range in northern Missouri, about 35 percent of 1-year-old does produce a fawn.
Other Missouri studies have shown that hunting is a big part of total mortality among rural deer. During a typical deer season, hunters take about 20 percent of the button bucks, 50 percent of the 1.5-year-old (yearling) bucks, and 20 to 25 percent of the does 1.5 years of age and older.
Under this harvest pattern we would expect the deer population to remain stable, with about 35 percent of the fall population being 6 months old, 12 percent of the population consisting of yearling bucks, and 9 percent of the population being bucks age 2.5 years and older (adult). Adding the last two percentages tells us that about one in five deer would have a visible set of antlers.
Now that we have an idea of the “normal” deer population, we can determine what might happen if we changed the harvest by deer hunters. For example, what effect would cutting button buck harvest in half—from 20 percent to 10 percent—have on overall deer numbers and the number of adult bucks?
Our model shows that after several years of reduced button buck harvest, the fall deer population would still be stable but it would be 3 percent larger than the“normal” population due to a 12 percent increase in the number of adult bucks. So, cutting button buck harvest in half would result in a small increase in the number of adult bucks.
On the other hand, if we reduced yearling buck harvest by half, after a few years we could see a 50 percent increase in the number of adult bucks, a significantly greater impact than achieved by a reduction in the button buck harvest.
The reason for the difference is that hunters take a much smaller proportion of button bucks than yearling bucks. In other words, there