Mature bucks can take your breath away. Whether it’s a frosty fall morning in the woods or a summer evening in an alfalfa field, the mere glimpse of a mature buck will make your heart race and a full sighting can leave you breathless.
Today we are far luckier than we were two decades ago with respect to the opportunity to hunt mature bucks. In 2003, nearly 50% of the antlered bucks shot in the U.S. were only 1½ years old, and only 22% were 3½ years or older. These percentages have changed dramatically over two decades, as we’ve documented in our annual Deer Report. Our newest report released later this month will reveal we are now hunting whitetails with the best buck age structure in recorded history!
We know mature bucks are fun to photograph and hunt. In that, they are important to hunters. However, they are also important to the deer population. Let’s define maturity and then look at the role mature bucks play in a deer herd so we can understand their importance extends far beyond simply being the most sought-after targets during hunting season.
Whitetail Buck Age and Maturity
Whitetail bucks generally reach skeletal maturity from 4½ to 6½ years and grow their largest set of antlers from 5½ to 7½ years. Most biologists refer to bucks 1½ to 2½ as young or immature, 3½ to 4½ as middle-aged, and 5½ or older as fully mature. For this article, I’ll combine middle-aged and mature bucks and consider 3½ years old or older as “mature.”
Mature bucks are magical creatures. Even dyed-in-the-wool meat hunters relish the opportunity to shoot one. They require knowledge, skill and time to produce, and many times they are even harder to harvest. Just as big fish and big trees suggest successful fishery and forestry programs, the presence of mature bucks is a positive sign for a deer management program. Here are four main reasons why.
Priming the Rut
Whitetails are social animals, and scent is their primary communication method. During the breeding season, signposts such as rubs and scrapes provide the location for scent deposition and information transmission. A growing body of research suggests pheromones are deposited at these signposts by mature bucks, and these pheromones may have a bio-stimulating effect on the breeding season.
Pheromones are chemicals secreted from a deer’s body that affect other deer. Once received via taste, smell, or other means, pheromones trigger special receptors and can cause various changes in the receiving animal’s physiology and behavior. How pheromone interactions work in whitetails is poorly understood, but their powerful influence in other mammals is well documented.
Research also suggests that primarily older bucks produce “controlling” pheromones that yearling bucks are not physically mature enough to produce. Some studies even suggest a buck reaching dominant status produces different pheromones than less dominant bucks of the same age.
Dr. Karl Miller, retired wildlife professor from the University of Georgia Deer Lab, adds that increased physiological stimulation of does by mature bucks via signposts may cause earlier and more synchronized breeding. This is due to the interaction between pheromones from mature bucks and the does’ reproductive physiology. While there isn’t definitive proof that priming pheromones exist in whitetails, researcher Louis Verme and his colleagues at Michigan DNR found that does penned with bucks experienced estrous earlier than those that were not.
As most hunters know, rubs and scrapes play central roles in deer social life immediately before and during the rut. The relative abundance of sign on a given area is directly related to the density of mature bucks, and areas with mature bucks can have 10 times as many rubs as areas without them.
“The presence of mature bucks suppresses the breeding activities of young bucks. This is good for the future health and growth of these young bucks and the health of the entire deer population.”
Noted researchers John Ozoga and Louis Verme found yearling bucks lacked the scent-marking behavior characteristic of mature bucks. In their study, mature bucks began making scrapes two months before any doe bred, whereas yearling bucks made only 15% as many scrapes and none until one week before the first doe bred. They also noted yearling bucks made only 50% as many rubs as mature bucks during the breeding season.
Signpost behaviors are important to the whitetail’s breeding ecology, and therefore the “priming” effect that mature bucks may have on the length and/or timing of the rut is reduced or absent when mature bucks are scarce.This priming effect from signposts likely has a stronger effect in southern latitudes as northern studies show the majority of does are bred during their first cycle even in the absence of mature bucks. However, this doesn’t discount the benefit of mature bucks to northern herds.
Suppressing Young Buck Rut Activity
Research shows young bucks engage in breeding and may sire nearly 30% of fawns even in populations where mature bucks comprise over 50% of the bucks. Of course young bucks sire a higher percentage of fawns in populations with fewer mature bucks. However, this is unfortunate because it is advantageous for yearling bucks to spend less time chasing and/or breeding does and additional time feeding and storing fat for the upcoming winter.
Yearling bucks that enter winter in better physical condition have higher winter survival rates and are able to contribute more spring forage to body growth and less to recovering the additional body weight lost during winter. Young bucks can handle the breeding requirements of a herd but they do so at their own nutritional expense. Therefore, the presence of mature bucks suppresses the breeding activities of young bucks. This is good for the future health and growth of these young bucks and the health of the entire deer population.
“Natural” Deer Population
Mature bucks are part of a “natural” deer herd. Archaeologists determined early deer herds had an advanced age structure by examining deer remains in Native American middens (refuse piles). Evidence in these middens suggested 20 to 26% of deer populations were 5½ years or older. Interestingly, data from modern-day unhunted herds show similar age structures.
Fortunately, most modern-day hunted herds have this age structure for does and an increasing number do for bucks. According to Dr. Dave Guynn, retired wildlife professor from Clemson University, when this age structure is achieved it ensures the behavioral and biological mechanisms that shape deer populations are allowed to function. Dave continues that the density, sex ratio and age structure of a deer herd should mimic a population regulated by natural predators and hunting by Native Americans. This natural condition provides for a nutritionally and socially healthy herd. It is only achieved when mature bucks are present.
Priming Hunter Enthusiasm
In addition to the biological benefits, mature bucks also provide additional recreational opportunities for hunters. The mere presence of a mature buck in the area can help get additional hunters afield or keep them afield longer. This interest can provide opportunities to further other aspects of a management program such as increasing the antlerless harvest in areas with overabundant deer herds or reducing the harvest of young bucks to help improve the age structure of the buck population. This interest also provides educational opportunities for hunters on deer and habitat management topics. Plus, multiple surveys show hunters support managing for a higher percentage of mature bucks in the population.
Finally, mature bucks can increase the enjoyment level of a hunt by leaving more rubs and scrapes for hunters to find and responding at a higher rate to calling and rattling. This allows hunters to take a more active role in the hunt. Calling or rattling in a buck can be extremely gratifying!
So, can deer herds exist without mature bucks? Sure, they can, but remember:
- Whitetail populations evolved with mature bucks.
- Their social order works best with mature bucks.
- Young bucks’ fitness can be enhanced by the presence of mature bucks.
- Hunting interest increases when mature bucks are present.
All of these points are good for the deer herd, for deer management and for the future of hunting. If you passed up a shot at a young buck this season, know that you did your part to improve the health of the deer herd as well as increase your chance of taking a mature buck in the future.