What is it about white-tailed deer that makes them so hard to predict?
You’ve heard the same story time and time again: A dedicated deer hunter spends the summer months meticulously setting up and monitoring game cameras to see what deer are likely to be using the property during the upcoming season. With some luck, a shooter buck turns up and all efforts become focused on learning his particular movement patterns.
By early autumn the stands are hung and he is still consistently showing up right where he needs to be. It’s now the night before opening morning and the hunter drifts to sleep, feeling as though tomorrow’s hunt will go exactly as planned.
By Kevyn Wiskrchen &
Dr. Stephen Ditchkoff
As you know if you’ve ever been this hunter, opening morning often does not go as planned, nor do many of the subsequent hunts throughout the season. Often, the deer you’ve worked so hard to pattern completely change their behavior or seem to disappear once you begin hunting them. Other times, you might successfully kill the deer you’re after but it usually doesn’t happen quite the way you had planned, and your success can often be attributed just as much to luck as skill.
What is it about white-tailed deer that makes them so hard to predict? For one thing, deer are perceptive creatures that seem to become more wary of their surroundings with age and experience. Deer are also highly adaptable, capable of employing a variety of behavioral changes to avoid hunters, depending on the situation at hand.
DEER RESPONSE TO HUNTING
Previous research has revealed much about how hunting pressure influences white-tailed deer behavior. Whether, and how strongly, deer respond to hunting activity can vary widely from one property to the next, however, and often depends on a variety of factors, including the amount of hunting pressure put on the herd, as well as the availability of escape cover. In a study conducted in Maryland by North Carolina State University, low levels of hunting pressure had no noticeable effect on the behavior of adult bucks except for causing occasional, short-distance flights when deer entered the immediate proximity of a hunter.
Only in nine of 23 instances when a buck came within about 100 yards of an occupied treestand did it bother to change direction or exhibit a flight response. Furthermore, flight movements were short-lived and bucks soon resumed normal activity within those same areas. An entirely different response was seen by Mississippi State University researchers who monitored adult bucks in Oklahoma that were exposed to one hunter for every 75 acres. Over the course of the two-week hunting season, bucks dramatically reduced their distance traveled and began utilizing smaller areas more intensively in what was interpreted by researchers as an effort to avoid being seen.
Behavioral changes were also observed among adult female deer during a study conducted out of the University of Florida. Adult does moved farther from roads where hunting pressure was concentrated. Although they did not reduce their home range in response to hunting, they began avoiding open habitats such as clear-cuts, and instead showed preference for swamps and mature timber with more cover.
In both previous examples, where deer showed a behavioral response to hunting, forests or bottomlands were a prominent component of the landscape. With the availability of habitats that provide ample cover, deer are likely to respond to concentrated hunting pressure by utilizing those areas more and avoiding open areas. In regions with mostly open terrain, however, deer might respond by expanding their movements, often venturing outside of their normal areas of use.
In a study conducted in South Dakota during the late 1960s, researchers reported that hunting activity resulted in deer making a number of long-distance movements extending 2 to 14 miles outside of their normal home range, and attributed these responses to the lack of avail- able cover on the landscape.
In general, previous research tells us that although hunting doesn’t always cause deer to alter their movements, higher levels of hunting pressure are more likely to elicit a behavioral response. Additionally, in prime deer habitat with an abundance of thick bedding areas and places to hide from hunters, deer will not need to go far to find security, and instead are likely to reduce their movements and start using cover more heavily when they feel threatened.
FALLING INTO A RUT
Without question, knowledge concerning the response by deer to hunting pressure is at an all-time high, and hunters everywhere regularly employ strategic approaches in an effort to reduce their impact on deer movements. However, as much as they claim to understand deer behavior, the actions of hunters tell a different story. For example, every avid deer hunter is familiar with the rut and some likely already have their calendars marked and are counting down the days until bucks will be chasing does again this fall.
Yet it seems most deer hunters also have a kind of rut they fall into once deer season begins. Consistent and repeated hunting patterns might render the behavior of hunters even more predictable to deer than deer behavior is to hunters, ultimately reducing the chances of bagging that trophy buck … or any deer for that matter.
While conducting research to examine movement and mortality patterns of deer in Alabama, we noted some disturbing patterns within the behavior of both deer and deer hunters. The combination of these patterns has the potential to significantly limit hunter success.
Deer hunters in Alabama were observed spending the vast majority of their time afield on weekends (Friday-Sunday), with far less hunting effort being expended throughout the rest of the week. This repetitive pattern is presumably driven by busy work and family schedules, leaving very little free time outside of weekends for recreation. Consider the impact this pattern might have on deer.
Hunters on public and private lands pile into the woods each Friday afternoon and head home on Sundays. During weekends throughout deer season, in contrast to weekdays, deers’ olfactory, audio and visual senses are bombarded with stimuli indicating that hunters are in the vicinity. As a result, deer likely feel considerable predatory (hunting) pressure during those few days each week that get hunted the most. By repeating this cycle of hunting pressure week after week, hunters might be making themselves easy to pattern and could be causing deer to adjust their behavior during the days when hunters are most active.
In order to examine deer movement relative to the observed hunting pattern, we had a number of adult, male and female, white-tailed deer fitted with GPS collars, allowing comparisons between deer behavior on weekends, when hunting activity was greatest, and the rest of the week. A preliminary look at the movements of 10 of these animals revealed an interesting trend.
Throughout the last five weeks of the season, which included the peak breeding period as well as the period of highest hunting pressure, daytime movement by deer was the greatest on Thursdays and Fridays, just before all of the hunters showed up.
By Saturday, daytime movement had already dropped 22 percent and by Sunday, daytime movement was down 34 percent compared to the start of the weekend. This rapid and dramatic behavioral response is a strong indicator that deer are responding to the increase in hunting pressure by reducing movement during daytime hours in an effort to minimize their probability of encountering a hunter.
THAT’S NOT ALL
Another interesting observation was their movement remained suppressed on Monday and Tuesday, even though hunters, for the most part, were not afield. We speculate that deer took a couple of additional days to assess the environment for danger before deciding that the risk associated with movement during daylight hours had subsided. By Wednesday and Thursday, daytime movement had returned to normal, just in time for the weekend and the next wave of hunters.
We also looked at three other indicators of deer activity and each time found the same basic pattern where activity declined throughout the weekend, remained low on Monday and Tuesday, and began return- ing to normal levels on Wednesday.
In addition to traveling less during daylight hours, deer tended to utilize progressively smaller areas through- out the weekend, but began moving more broadly across the landscape later in the week once hunting pressure had declined. Deer also became more nocturnal, allocating more of their movement to nighttime hours.
Finally, deer were inactive for longer periods during the day, staying bedded during more daylight hours as the weekend progressed. Each of these changes in behavior occurred simultaneous to the influx of hunters to the woods and returned to normal within a couple of days of hunters leaving.
So, who is patterning who?
WHAT THIS MEANS FOR HUNTERS
Although we’ve known for some time that high levels of hunting pressure can influence deer move- ment, it’s not often we see such a clear change in behavior that directly reflects the tendencies of hunters.
Research findings such as these have some major implications for all deer hunters, particularly those who hunt on public land or share private land with others. In areas that receive a lot of hunting pressure, and that also have plenty of cover, creating opportunities to harvest a deer could be challenged by a sudden and dramatic decrease in deer movement.
As you can imagine, if deer are moving less during daylight hours and confining their movements to the thickest cover on the property, it could explain a lot about why deer have a tendency to “disappear.”
Our preliminary findings suggest that a hunter’s chances of killing a deer start to decline after the first day of the weekend and don’t improve until hunting pressure has subsided for at least two days. This isn’t to say that deer, including some monster bucks, can’t be killed on weekends. Nonetheless, for those who hunt in areas that are heavily pressured on weekends and less pressured throughout the week, which appears to be common, it’s possible the deer are changing their behavior to minimize the chances of a human encounter.
The harsh reality is this phenomenon is impacting practically all hunters, even those who hunt private property and are extremely careful regarding the pressure they put on the deer herd. Because white- tailed deer are capable of occupying areas much larger than the typical parcel of private property, there is very little chance the deer you hunt are exposed only to your hunting pressure.
Although some rare exceptions might exist in the case of extremely large tracts of private land and high-fence facilities, the vast majority of hunters will have to contend with the patterns of hunting pressure on adjacent properties and the influence they have on the deer they hunt.
So, have white-tailed deer learned how to predict when to take cover based on the repeated patterns of hunters? We won’t go that far — however, the data suggest that white-tailed deer are highly perceptive creatures with an uncanny ability to know when hunters are most active.
The tendency of hunters to concentrate their hunting efforts on weekends, with much less time spent hunting throughout the rest of the week, appears to be a huge red flag to deer, indicating that they should shut down their movements until the storm passes. In addition, by spending a lot of time in the woods on days when deer are least active, hunters might be limiting their chances of harvesting deer, particularly older individuals with more experience dealing with hunters.
Sadly, it seems that sportsmen are paying the price for the busy lives they lead. While a dramatic response in deer movement to hunting patterns might be of little concern to some, those with a limited number of days to spend in the field or who want to maximize the likelihood of bagging a deer might feel differently.
The good news is that hunters can use these findings to their advantage to increase the chances of bringing home some venison this fall. We suggest that in addition to trying to pattern the deer on the property you hunt, you take a little time to examine your own patterns. If you find that your hunting behavior is highly predictable, then consider developing a plan to break out of the rut. In doing so, we’re confident that your time afield will become much more productive and satisfying.
— Dr. Steve Ditchkoff is a professor in the School of Forestry and Wildlife Sciences at Auburn University. He manages the deer research program at Auburn and has been conducting research on white-tailed deer for 25 years.
— Kevyn Wiskirchen is nearing completion of his M.S. degree at Auburn University, working with white-tailed deer under the supervision of Dr. Steve Ditchkoff. His thesis research is focused on white-tail mortality patterns and responses to hunting pressure.
— Karns, G.R., R.A. Lancia, C.S. DePerno, and M.C. Conner. 2012. “Impact of Hunting Pressure on Adult Male White-tailed Deer Behavior.” Proceedings of the Annual Conference of the Southeast Associate of Fish and Wildlife Agencies, 66:120-125.
— Kilgo, J.C., R.F. Labisky, and D.E. Fritzen. 1998. “Influences of Hunting on the Behavior of White- tailed Deer: Implications for Conservation of the Florida Panther.” Conservation Biology, 12:1359-1364.
— Little, A.R., S.L. Webb, S. Demarais, K.L. Gee, S.K. Riffell, and J.A. Gaskamp. 2015. “Hunting Intensity Alters Movement Behaviour of White-tailed Deer.” Basic and Applied Ecology, 17:360-369.
— Sparrowe, R.D. and P.F. Springer. 1970. “Seasonal Activity Patterns of White-tailed Deer in Eastern South Dakota.” Journal of Wildlife Management, 34:420-431.
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