October 28, 2010
Scrapes. Hunters and biologists are fascinated by them. Yet despite all the research and investigation carried out by both professional scientists and avid sportsmen, we still don't completely understand them, which only adds to their allure.
Thankfully, research has revealed a fair amount. Biologists pretty much agree that scrapes are (for the most part) visual and olfactory signposts, created by deer as a means of communication. What we're a little hazy on is what those deer are trying to communicate.
Unfortunately, sometimes well-intentioned efforts to translate that science into something useful for hunters have led to a preponderance of misinformation. For instance, somewhere along the line somebody proposed the notion that only mature bucks make scrapes, and it is their way of announcing their dominance and readiness to breed. This half-truth has been perpetuated to the point where many hunters accept it as gospel.
The truth is not quite that simple. Mature bucks do indeed sometimes scrape in the presence of a subordinate buck to assert their dominance. However, when a more dominant buck (notice I didn't say the dominant buck) is not around, subordinate bucks also scrape. It is not unusual even for yearling bucks to open a scrape, or to utilize a scrape created by an older, more dominant buck. Does also use scrapes.
Part of the misunderstanding is because not all scrapes are created equal, or for the same purpose. Research tells us scraping activity peaks just before the peak of rut, which implies it has some function related to breeding. For the most part it does.
However, the aforementioned example may occur well before the breeding or courting phases of the rut, during what some hunters refer to as the pre-rut. Bucks are still sorting out the dominance hierarchy, and like an angry bull, one may sometimes paw the ground merely as a sign of aggression. This type of scrape will likely never be re-visited, and should be easily distinguishable, for reasons that we'll discuss. Obviously, setting up over this type of scrape would be a waste of your valuable hunting time.
As the breeding season approaches, waning amounts of daylight trigger physiological changes in deer. An increase in testosterone motivates bucks to begin scraping. They then rub-urinate by grinding their tarsal glands together and peeing down their legs so the urine and tarsal scents combine before running into the bare soil, where they remain as an olfactory signpost.
Priority Number One
One of the most important aspects of a scrape is the one most easily overlooked. Scrapes occur in a vast array of conditions, habitats, frequency and abundance. With very little exception however, those that are used on a regular basis have one thing in common: an overhanging "licking" branch, which, for the hunter at least, may be more important than the scrape itself.
Not every deer that visits the scrape will pee, or scrape the ground. They all will tend the branch. Typically, they smell it first, presumably to see who's been by recently. Then, they rub the branch with their forehead and pre-orbital glands, depositing scent from each. Sometimes they will mouth or lick the branch too--thus, the name. They may be tasting it, or drawing scent into their vomeronasal organ, which is located in the roof of the mouth. This is the same organ they draw airborne scent across when lip curling--sometimes called the flehmen response.
That's the intriguing part. The frustrating part is figuring out how to utilize this knowledge. "Simple," you say. "Find a scrape and hang a stand nearby." There are two glaring problems with that. First, deer don't visit those scrapes very often. Second, research also tells us that roughly 85-percent of scraping occurs at night. So is hunting scrapes a waste of time? Not necessarily. While mature bucks may not walk right up to the scrape in daylight, they will often wander by downwind, scent-checking the air to see if any hot does have been by. Does, meanwhile, may visit the licking branch, drawing randy bucks out of hiding. Simple solution: don't set up over a scrape; but set up 50 to 100 yards downwind.
That may work great in some situations. But what if a scrape location doesn't allow for that, or you can't find any scrapes on your happy hunting grounds? Simple again. Make your own.
From his (pardon the pun) groundbreaking work on scrape making in Michigan's Upper Peninsula, Dr. John Ozoga discovered a couple important things. First, that an overhanging branch, approximately five to six feet above the ground is a key characteristic of a scrape site. Second, and more importantly, Ozoga found that bucks could be induced to scrape beneath human-positioned limbs. Simply by tying or nailing overhanging branches at the right height (and in the right location), he was able to provoke deer into scraping. It didn't take hunters long to figure out if you scrape away the duff and pour in urine-based scents, these mock scrapes can be made even more effective. And we now know that adding glandular scents to the licking branch further enhances their potential.
Will it work all the time? Of course not. Just as with rattling and calling, conditions and timing must be just right. Working in and around scrapes you must redouble your scent control efforts. Deer visit these spots specifically looking for odors, and may spend a good deal of time dissecting individual smells. One false move and it's over. If you can make it work however, you'll know you beat the best in the business at their own game.