Hunting > Whitetails

What Pressured Bucks Do

GPS tracking collars are revealing how bucks change their patterns when the hunting season starts.


Though the buck stayed visible less than 10 seconds and its candelabra antlers flickered into view just once, I still kick myself 20 years later for not trying to stop him before he vanished into the bog of black ash and white cedars. I should have grabbed my grunt tube or just called with my mouth. Heck, even yelled. But that’s hindsight. The three deer ahead of him had filtered through the forest single-file, the lead doe stopping nervously every few steps to scan ahead and check her followers. When the buck appeared—and one glance confirmed it had the best antlers I ever saw in Upper Michigan’s Ottawa National Forest—I figured he would pause at least once, just like the doe. Poor assumption. He neither paused nor followed the first three deer through my possible shooting lanes. Where he went I’ll never know.

If only that buck had been part of a university research program and wearing a collar with a GPS transmitter. I’d like to know where it walked to dodge death that morning and where it spent the day. For that matter, where was it the night before and at dawn? When I spotted him and his three companions, were they fleeing hunters to the west, as their behavior suggested? And, just out of morbid curiosity, did someone shoot him later that day or season, or did he die a few winters later when worn down by age?

Granted, that buck was long dead before today’s gee-wiz GPS collars were available. These devices record a deer’s precise location at programmed intervals, and fall off when triggered remotely. After retrieving the devices, researchers download all the GPS data into computers, and then plot the deer’s movements over several months.

Some researchers don’t stop there. Some are also equipping nearby hunters with portable GPS units that record their locations throughout the day. By plotting the time and place of the hunters’ locations, and comparing them to those from collared bucks, researchers hope to document how whitetails respond to hunting pressure and human presence, and maybe even hunting tactics and weather-related influences.

Three such studies, two by Auburn University and another by Mississippi State University, got under way during the past two years. Although the researchers are still collecting and analyzing data—and are far from realizing their studies’ potential and the whitetail’s many secrets—they’re already documenting how sensitive bucks can be to even minor human intrusions.

Shy By Nature?
One thing to remember, however, is that every buck responds differently to human activity; in fact, some bucks seldom leave cover during daylight, no matter how few humans they encounter. Gabriel Karns, an Auburn University researcher and doctoral student, previously conducted research at Maryland’s Chesapeake Farms through North Carolina State University. He recalls a secretive 6½-year-old Chesapeake buck whose home range covered a mere 100 acres. The buck hunkered almost every daylight hour in a dense 20-acre saltwater marsh about 75 yards from a crop field. In October 2007 the buck entered the field just once during daylight, even though gun season hadn’t yet opened and only one or two archers were hunting deer on the 3,000-acre property.

“There was no reason to be a recluse at that time,” Karns said. “That buck would weave his way into that marsh before daylight, stay until dark, and hit the cornfield night after night. He later died of EHD (epizootic hemorrhagic disease). If we hadn’t had a GPS collar on him, he would have rotted away and turned to mush without anyone knowing.”

Most bucks at Chesapeake Farms aren’t so cautious, though. “If someone had sat on that field they would have seen some of our collared bucks (all of which were at least 2½ years old) 15 to 25 of 30 days,” Karns said. “Of our 20 collared bucks, hunters had a chance to kill 16 or 17 of them during the gun season. You could have shot some of them Monday, Tuesday, Wednesday and three times on Sunday. They had a knack for showing up in the wrong place at the wrong time. We asked hunters not to shoot bucks wearing a collar, so that was the only thing saving some of them.”

The Disappearing Act
Likewise, hunters in a Mississippi State University study on a 4,600-acre Oklahoma ranch could not shoot collared bucks; however, as with Chesapeake’s bucks, collars didn’t protect them when they crossed onto neighboring properties. Even so, none of the 27 Oklahoma bucks collared in 2009 were shot. In 2008, only one of the 25 collared bucks was tagged. The bucks ranged in age from 2½ to 6½-plus (3.6 average) in 2008, and 2½ to 8½-plus (3.9 average) in 2009. Soon after the 16-day firearm season opened the bucks became elusive. When Andrew Little, a master’s degree candidate at MSU, pooled the 2-year totals, he found hunters spotted 38 percent of the collared bucks on opening weekend, 23 percent the second weekend and only 3 percent the third weekend. So hunters never saw 63 percent of the bucks opening weekend, 77 percent the second weekend and 97 percent the third weekend.

Those declines in sightings weren’t because all the bucks found sanctuary on neighboring properties. When Little discussed his research at the 2010 Southeast Deer Study Group meeting in San Antonio, Texas, last March, he had analyzed movement data on 34 bucks from the two seasons. Although all 34 bucks left the ranch at times during the hunt, none abandoned it full-time. The bucks spent anywhere from 10 minutes to several hours off the property during the hunt, and only two each year spent 80 percent of their time “across the fence.”
For the most part, the bucks hunkered down on the study ranch and seldom moved far during daylight. “They obviously got smart in a hurry,” Little said.

Not only did the bucks grow increasingly wary during hunting season, they started wising up when hunters first showed up for a two-day scouting and stand-placing opportunity in mid-November. This was about a week before the hunt and coincided with the deer’s peak-breeding period. From then on, the bucks steadily decreased their movements all the way into the post-season—the same pattern Karns documented in his 2008 Maryland study.

Those patterns also emerged in two statewide deer-observation surveys begun in 2009 by the Wisconsin Department of Natural Resources. From mid-September through early January, the DNR asks Wisconsin hunters to log onto its deer-survey website after each hunt to report how many bucks, does and fawns they saw.

Deer observations peaked in late September in both Wisconsin surveys, about two weeks after archery season opened, and then declined steadily before bottoming out at the end of the general firearm season in late November. Deer observations then rose during early December, peaking mid-month at levels comparable to mid-September.

Keith Warnke, the Wisconsin DNR’s chief deer ecologist, cautions not to read too much into one year’s worth of data. Still, he was intrigued by the steady decline in deer sightings once hunters went afield, which includes small game, turkeys and waterfowl hunters.

“The numbers show a little bump in deer sightings in late October and early November during the rut, but the general trend moved steadily downward from about Oct. 1 to Dec. 1,” Warnke said. “That’s also despite the fact visibility in the woods is much better after leaves fall in mid-October. Similar declines in the online survey give this data some credibility.”

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1 Response to What Pressured Bucks Do

Ray wrote:
November 29, 2013

Very interesting article! Where can I find updates on the studies conducted?