by Patrick Durkin - Wednesday, September 22, 2010
erhaps deer hunting’s greatest charm is that one routine head turn can flip your day from “ho-hum” to “holy Hillary!”
Or words far stronger.
While hunting the vast forests of northeastern Minnesota in November 2008, I nestled into the cover of a large spruce in the breezy, pre-dawn darkness. Although my view was limited, the site overlooked a good travel junction for whitetails along uplands studded with poplars, spruce and balsam fir. Behind me, the land tapered into lowlands of tag alders, dogwood and black spruce.
About 10:10 a.m. I fired up my GPS unit, thinking I’d kill time by naming and locking in my location. When glancing up from its “welcome” screen, I saw a buck walking between poplars 40 yards away. As I jammed the GPS back into a pocket, the buck went to a large balsam about 50 yards away, bit down on a low-hanging branch, and hooked and thrashed the boughs overhead.
I first judged its antlers too small, but then reconsidered when the buck turned broadside. His blocky body seemed to overload his legs, making them look stumpy. I raised my binocular for a better look. As the buck twisted its antlers in the boughs, I saw that the right beam looked like a magnum celery stalk topped by a caribou shovel.
My rifle replaced the binocular, and the buck collapsed seconds later when the .35 Whelen slug broke his shoulders. My wait of four-plus seasons covering 20-plus days of hunting near Ely ended in less than 30 seconds, the time it took to turn my head, spot the buck, dismiss it, rethink it and shoot.
After admiring the buck and agonizing over how close I’d come to letting him walk, I studied the shredded and gnarled boughs that had held his interest just long enough to doom him. The ground beneath those overhanging branches was rock-hard and snow-covered. I knelt and brushed away the white stuff, revealing a frozen oval slate scratched and pocked by hooves, almost like a fossil.
I couldn’t help but smirk. I had hunted here before, but never knew I was downwind of a scrape until the buck marked the balsam boughs above. Without trying, I had verified what researchers have said for years: An individual scrape is seldom a destination. If deer trails were highways, scrapes would be points of interest along the way. Just as few people go out of their way to read historical markers, deer seldom visit scrapes unless they’re conveniently located among other attractions.
In other words, I shot my buck while he checked in from a wayside. He hadn’t come here to cross this particular scrape off his daily “to-do” list.
The Purpose of Scrapes
Although researchers caution hunters not to read too much into scrapes, these signposts do serve vital roles for white-tail deer. Bucks communicate with each other through scents left at scrapes, and chemicals deposited in scrapes by buck urine probably trigger hormone changes in the doe population to synchronize the breeding season. Bucks and does spend most of the year apart from each other. They likely need a scent cue to trigger their brief mating season.
“Peak scraping activity is always about two weeks before peak breeding,” said professor Karl Miller at the University of Georgia (UGA). “We see a lot of buck activity at scrapes as they mark branches, paw the ground and urinate. They’re establishing their presence and affirming their hierarchal position. Once breeding starts, scrape activity goes down. But how do we explain the doe activity we’ve documented at scrapes? Their presence isn’t a coincidence.”
Research at UGA by Karen Alexy in 1999 recorded 562 visits to nine scrapes over two autumns by wild, free-ranging deer. By using motion-triggered video cameras, Alexy documented that females accounted for more scrape visits than males (62 percent to 38 percent), but only 21 percent of females pawed, licked, urinated or otherwise “interacted” with a scrape. In contrast, 52 percent of buck visits included one or more of those actions.
Alexy conducted her study with professor Miller’s guidance. “Does are smelling the scrapes and sometimes even licking the branches,” Miller said. “They’re getting information. They’re probably identifying the most fit reproductive partners, as well as the more inferior ones. It’s likely that rubbing, scraping and urinating by bucks is very important in ending the nonbreeding season and synchronizing the onset of breeding.”
Miller notes that UGA researchers found buck urine in autumn causes a two- to three-fold increase in a doe’s progesterone levels. As hormone levels rise, the ovaries start working, and within two weeks, the ovary’s follicles release eggs needing fertilization.
“Does do not visit scrapes to breed,” Miller said. “Peak breeding is still two weeks away. But as the buck’s testosterone levels increase, the doe probably detects those changes in the buck’s urine. It’s like people giving a urine sample at the doctor’s office. It reveals what’s going on inside the body.”
Is it possible does are leaving signals, or “calling cards” about their readiness to breed, as some hunters speculate? The timing of peak scrape activity, and the lack of routine scent-marking by does, suggests no.
“This idea that does urinate into scrapes and bucks smell their urine and take off after them is a misconception,” said professor James Kroll of Stephen F. Austin University in Texas. “The tests we’ve done convince me you cannot put doe-in-heat urine into a bottle. There are at least 90 compounds in doe urine and most of them are volatile fatty acids that evaporate in seconds.
“We even put does into estrus, collected mucus from their vaginas, immediately put it into an ultra-freezer, and tested it on bucks,” Kroll continued. “We didn’t get any reaction. It was worthless, but that’s logical. If a doe left a long-lasting scent every time she squatted and urinated during the rut, the woods would be a very confusing place.”
Likewise, by itself, buck urine does not trigger scraping activity. “Much of what releases the buck’s scraping activity is the physical structure of the scrape; the overhanging branch, the pawing, the dirt,” Miller said. “I mean, if you have maybe five bucks per square mile of woods, and each buck urinates 10 times a day, you have 50 new urine spots daily. That would be lots of new scrapes every day.”
Place and Size
Complicating things further for hunters is that some scrapes communicate nothing beyond a simple, “Back off!” When a buck feels crowded by another buck, it often paws the ground to bluff or warn the other. These pawings pop up anywhere a deer happens to be feeding or walking when it spots a challenger. Even if the aggressor also raked brush or branches, it’s unlikely it or any deer will revisit the site.
We can also read too much into a scrape’s size. A large scrape might suggest lots of buck activity, either by individual bucks making repeated visits, and/or many bucks making individual visits. But scrape sizes can be misleading. Grant Woods recalls a two-year research project on his Missouri property by graduate student Josh Braun. They used 11 motion-activated video cameras to monitor active scrapes.
“In one case we had a 2-foot-diameter scrape that recorded more events than an 8-foot scrape,” Woods said. “The 8-foot scrape just happened to be where one buck got really excited and tore the place up. Of the many scrapes we studied for two years, we didn’t find any scrapes that were like a major buck hub. There was no scrape where all the bucks came in and hung around.”
And contrary to some long-held theories, scents left in scrapes by older bucks don’t keep inferior bucks away from the site. Young bucks remain wary while scraping, but they do scrape. Alexy reported as many as 13 bucks visited one scrape, while other scrapes got hit by nine different bucks.
Even though about half the bucks Alexy identified revisited at least one scrape in her study, she found no evidence that bucks systematically roamed the property, checking and monitoring a scrape network. In fact, she reported it was rare for a buck to visit more than one of the nine scrapes she monitored with her video cameras.
A Time to Scrape
More challenging, though, are timing issues: Scrapes are most attractive to deer for a relatively short period. About 92 percent of the 562 scrape visits in Alexy’s study occurred between Oct. 1 and Dec. 9, but Miller said about half of those occurred during a one-week period in late October. Hunters who miss that particular week obviously have poor chances of scoring at a scrape.
But even if you’re on site, alert and downwind, research data suggest few deer will appear in daylight. Alexy’s study showed most buck visits occurred at night (85 percent), as did most doe visits (75 percent). Woods estimated more than 90 percent of scrape visits he and Braun documented in Missouri occurred at night, and Kroll estimated 98 percent of scrape visits he documented in Texas were at night.
None of the researchers attributed the deer’s nocturnal behavior to hunting. “Our study was on a free-ranging deer herd, the area has extremely light hunting pressure, and there’s no reason for them to be that nocturnal, but deer are just extremely nocturnal,” Woods said.
Alexy suggests daytime scrape visits are rare because scent communication is more important in low-light conditions. Scrapes, quite simply, are “designed” for this type of messaging. For instance, she cited a 1971 study reporting black-tailed deer sniff each other’s tarsal glands most often at night “possibly to aid in identification at night.”
Further, John Ozoga, a retired researcher for Michigan’s Department of Natural Resources, long ago documented that deer most often scrape along field edges, woodland roads, forest openings and inside woodlands where the understory is fairly flat and open. “They prefer some leaf litter, no dense grass, easily exposed dirt and little underbrush,” he said. “These tend to be places deer avoid in daylight, but move through easily at night.”
Increasing the Odds
As my hunt at the beginning of this article suggests, however, a few lucky hunters shoot bucks each fall at scrapes. Consider the following ideas for increasing your scrape-hunting odds.
Before the hunting season, locate well-used scrapes from the previous year. In his 1989 research, Ozoga reported deer reopened 16 of the 20 scrapes (80 percent) he monitored. Alexy reported similar results in 2001, with deer reopening nine of 12 scrapes (75 percent) she monitored.
To make scrapes even more enticing, Woods suggests a basic element: dirt. A whitetail’s favorite odor might be from freshly turned soil.
“The combination of an overhanging branch and fresh scent seems like a very important scrape attractant,” Woods said. “For scent, it’s hard to beat fresh dirt. That scent lingers. Even humans, with our dull olfactory skills, can smell it yards away, so imagine how far deer can smell it. And really, freshly pawed dirt is fairly uncommon in the deer woods. It’s usually associated with food or scrapes. Maybe it makes them curious. So, I’ll rake out a scrape 3 or 4 feet across.
“The same goes for broken branches,” Woods continued. “When bucks mouth and rack that overhanging limb, they break its twigs and bark, which produces scents that linger. Bucks need visuals and some forehead stimulus. All scent-marking, with few exceptions, starts with that.”
Miller and Woods agree it’s smart to place stands at least 20 yards downwind of scrapes. “I do think bucks scent-check scrapes without actually visiting them,” Miller said. “For our research, we could project the camera out 20 to 30 yards from the scrape. We caught deer moving by on the camera’s periphery, particularly downwind of scrapes. If a buck can get the information he seeks without walking all the way in, particularly during daytime, why not? We thought that might be what’s going on.”
Miller also suggests choosing scrapes with as many “value-added” features as possible, whether that’s nearby trails, favorable winds, ridgeline saddles, terrain pinch-points or anything else that funnels or pulls deer to specific spots where they want to be—or can’t avoid—in daylight.
“We had one scrape (in Alexy’s study) that was visited a lot,” he said. “It was near a mulberry tree, and deer absolutely love mulberry leaves as they’re falling. The scrape didn’t draw deer there. It was mulberry leaves. While the deer were eating, they opened a scrape and then visited it, since they happened to be there anyway.”
Kroll agreed scrapes are of secondary importance. “A buck’s activity pattern will always be shaped like a dumbbell, wide on both ends at the bedding and feeding areas, and narrow in between,” he said. “The area in between is where he most likely passes through on cruise control. He doesn’t know it as well as his bedding or feeding areas. I’ll set up near his bedding area and hope he leaves before dark. Most big bucks get killed in the afternoon.”
What Really Works
What if all those ideas don’t pan out? Woods shakes his head. “I wish I could look at our results and find a bottom-line summary, a novel place no one else has figured out,” Woods said. “But there isn’t one. It will always come back to the basics, and being a good woodsman. If you hunt a scrape, its location is its most important feature.
“The way I look at it, a deer spends 90 percent of its time traveling in areas where the odds favor its survival,” Woods continued. “You have to find that 10 percent area where the odds favor you. Deer give up those odds when the convenience of going from Point A to Point B is too much to resist. That’s where they take chances. Look for the edge of a hill or a bend in a river that forces them through a particular spot. If you find a scrape there, the odds favor you even more.”
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