Science of Hunting Pressure
How much pressure will change deer patterns? That depends
Under hunting pressure, deer mostly retreat to thick cover. (Steve Bowman photo)
This is the fourth and final in a series of articles looking into the science behind whitetail deer
Read Part I: Science Of Deer Vision
Read Part II: The Science of Antlers
Read Part III: Science Behind Deer Activity
As long as we’ve hunted whitetail deer, questions have come up about the effects of hunting pressure on our quarry.
Does hunting activity push deer out of core areas? Do deer “go nocturnal” in response to hunting pressure? Do whitetails push deeper into heavy cover to remain unseen by human predators?
The answers depend on multiple factors.
It won’t come as a surprise that deer often respond to hunting pressure by altering their daily activity patterns. But it might surprise hunters that sometimes the opposite is true, and despite increased hunting pressure, whitetails don’t always respond by changing their movements.
Of course, there’s ample evidence – and not just the anecdotal variety offered by your buddies at deer camp – that deer are profoundly affected by increases in hunting pressure. A 1998 Florida study showed that the average distance of deer to the nearest road and the amount of nocturnal activity were greater during the hunting season than during times when hunting season was closed.
The same study reported that deer “avoided clear cuts, regenerating pine stands, and other open habitats and preferred the dense cover of swamps and mature forests.”
Likewise, a Connecticut study of a controlled hunt revealed that deer retreated to areas of “dense vegetative cover” during the hunt. Other studies have shown that, in the absence of such dense cover, deer flushed by hunters may move long distances and may leave their annual home ranges.
But these findings don’t always hold true. More than one study has indicated that deer stay within an established home range in response to increased hunting pressure (perhaps an example of feeling safe and secure in familiar surroundings).
A 2008 Maryland study reported that disturbance by hunters “produced a behavioral response in only half of the encounters documented.” And even in those cases, the flight response was temporary and there were no changes in daily habits or shifts in home ranges.
Whitetail responses to hunting pressure can be highly variable. The amount of hunting pressure plays a part, as well as the density of the deer herd and the habitat type. Other factors that contribute to different behavioral responses include a deer’s age, sex and its prior experiences.
Males and females may react differently to hunting pressure. One study showed that does react to pressure by moving greater distances and covering larger areas during hunting seasons than during non-hunting seasons. The study found that such movements increased when hunter activity exceeded roughly one hunter per five acres. (It should be noted, however, that the “critical level of disturbance” likely varies based on different types of habitat.)
Meanwhile, bucks in the study did not react to pressure by altering their movements. And other studies have shown that bucks “may variably increase or decrease movements” in response to hunting pressure.
Hunting pressure in the form of hunting dogs also has been studied, and the results are somewhat surprising. Deer pursued by hunting dogs showed a strong commitment to seasonal and annual home ranges. Even though some left their home ranges, most all of them returned to their ranges and resumed normal activity within 24 hours.
So how much pressure is enough to alter deer patterns in your neck of the woods? A lot depends on what your neck of the woods looks like and the individual deer.
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