Dennis Anderson
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The question of how much “intelligence” white-tailed deer possess is one that hunters ask themselves often, as do deer researchers. Or maybe intelligence is the wrong word. Perhaps whatever smarts a deer has — and most seem to have plenty — should more accurately be described as instincts.

Case in point: Last weekend during the opening of Wisconsin’s deer season, our bunch of 16 hunters saw far more deer on Saturday, the first day of hunting, than on Sunday, the second day.

OK, you might say, what’s unexpected about that? When hundreds of thousands of hunters enter a state’s woods and fields, and shooting commences, wouldn’t an animal’s reasonable response be to flee, hide or travel only at nighttime?

Clint McCoy is among hunters who have long been intrigued by these and other white-tailed deer behaviors. A deer biologist with the Ohio Department of Natural Resources, McCoy in 2014 undertook a deer research project when he was a graduate student at Auburn University, the results of which suggest a whitetail’s survival instincts and, yes, perhaps, intelligence, can’t be overestimated.

McCoy’s study area was a 6,000-acre parcel in South Carolina’s low country managed for timber and hunting. On it are more than 100 deer stands.

The project began with the capture of 37 white-tailed bucks. Some were caught in trap nets, others with dart guns. The bucks represented four age groups about equally: yearlings, 2½-year-olds, 3½-year-olds and bucks older than 4½ years.

The bucks were fitted with GPS collars that transmitted location beacons every 30 minutes between Aug. 24 and Nov. 24, a period that included the rut, the peak of which, in that region of South Carolina, occurs between Sept. 20 and Oct. 30.

Primary among McCoy’s multiple goals in conducting the research was to determine whether a relationship existed between the amount of time a stand was occupied by a hunter and the bucks’ movements.

To begin, using GPS coordinates, McCoy established “danger zones” that extended as far as 150 yards from each stand. Bucks entering these areas during daylight while a stand was occupied were believed to be likely harvest targets.

McCoy also knew the amount of time each stand was occupied. So he overlaid buck movements transmitted by the collars with the stand occupation information to calculate whether, and if so, to what degree, the two were correlated.

Put another way, did the repetitive presence of a hunter in a stand cause deer to shy away from the stand?

“Initially, our interest was to determine movement of bucks during breeding season,” McCoy said last week by telephone from Ohio. “As you might expect, their movements did increase and expand as the rut continued. But this was not because they were ‘roaming’ looking for does in estrus. Rather, they appeared to expand their range only after most available does in their area had been bred. Then they started ranging wider.”

Conversely, McCoy found, hunting pressure didn’t appear to cause bucks to leave their usual ranges. Instead, the bucks reacted to a hunter’s presence in a stand by confining their movements to nighttime, while staying in the same general area.

“We found the odds of a collared buck entering one of the danger zones around a stand were reduced by half after only 12 hours of hunting,” McCoy said.

McCoy chose 12 hours as a time frame for this calculation because it equated, generally, with a weekend’s worth of hunting — three hours each in morning and evening in a stand on Saturday, with similar time spent in the stand on Sunday.

As is typical in Southern states, the stands were positioned near food plots. Before hunting began, McCoy found, one in three visits to the plots was made in daylight. By season’s end, the proportion was one in 20.

“We also looked at how long it takes for an area around a particular stand to ‘recover’ for deer once the stand has had a hunter in it,” McCoy said. “What we found was that once a stand had been hunted, the bucks responded almost immediately by avoiding the stand or visiting it only at nighttime. And that avoidance usually lasted three days.”

Because McCoy collared bucks of varying ages, he could assess whether the older bucks were cagier in their avoidance techniques than the younger bucks. Such, after all, is the reputation of old bucks among hunters.

“We wanted to tackle the age-old question of whether old bucks are better at outsmarting hunters than younger bucks and therefore the older bucks are inherently more difficult to kill,” McCoy said, adding:

“We couldn’t find any difference between the movements of the older bucks and the younger bucks. Since then, I’ve I thought about this frequently. Maybe the older bucks just appear smarter and more difficult to kill because you don’t see them as often. After all, there are far fewer of them in a deer population than there are younger bucks.”

Best spots for best times?

Many hunters don’t have a choice where they sit during deer season. They have only one or perhaps two stands to choose from.

Those hunters might want to schedule their stand time prudently.

“Our data strongly suggest the more seat time you spend in a given stand, the less likely it is you’ll see a deer there,” McCoy said, adding:

“It’s really easy these days when hunters have trail cameras and can see a buck or bucks moving near a given stand before the season, to think that if he sits in that stand time and again, the bucks in the trail camera photo will show up eventually.

“I don’t do that anymore. Now I reserve my best stands for the best times of the season. And I try not to overhunt them.

“Otherwise, as our data show, a hunter can shoot himself in the foot.”

Dennis Anderson danderson@startribune.com