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Scrapeology 101


Whitetails purposely employ many different types of scrapes to convey different messages


October 01, 2007
The popular deer hunting literature provides an amazing array of jargon relating to whitetail scraping behavior. One will find mention of boundary scrapes, territorial scrapes, perimeter scrapes, trail scrapes, travel lane scrapes, pause scrapes, unclaimed scrapes, doe scrapes, community scrapes, communal scrapes, hub scrapes, primary scrapes, secondary scrapes, breeding scrapes, and the list goes on.

To the uninformed, it might appear that we have scrapeologists in our midst.

The implication here, of course, is that whitetails purposely employ many different types of scrapes to convey different messages. Depending upon where and when they are made, and whether or not they are reused, writers have conjured-up varied terminology — seldom agreed upon among themselves — to identify specific scraping situations.




In order to help unravel some of the mysteries surrounding scrape behavior, Carefully consider the anatomy of a scrape and the physiological basis behind such behavior. Robert Peltz photo

Quite frankly, it's a bit overwhelming — and probably rather intimidating to any serious hunter who strives to stay up with current thinking.

I'm the first to admit that scraping behavior, best described as one type of sign posting, represents a highly complex form of scent communication among whitetails. Unfortunately, outdoor writers have taken tidbits from the scientific literature and blown them clear beyond firm scientific turf. I doubt if any other subject relating to whitetails behavior has been more elaborately abused, or more fictitiously presented, than that of scrape-making — largely because it's so poorly understood.

A Bunch of Bull

Karl Miller, Larry Marchinton, and their students at the University of Georgia probably have contributed more to our understanding of whitetail signposting than any other researchers around. I asked Karl what he thought of the many types of scrapes identified in the popular press.

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"You want my honest opinion?" he responded. "I think it's a bunch of bull..."

A terse reply, indeed. But in my view, it's an accurate one.

Miller warns, "the more we learn about scrape behavior, the more we realize how little we really understand it."

That's the mark of an astute scientist, because knowledge invariably generates more questions than answers. I'm highly suspicious of the outdoor writer with all the answers but very few questions.

Stick To Basics

In order to help unravel some of the mysteries surrounding scrape behavior, Miller suggests that we stick to basics: Carefully consider the anatomy of a scrape and the physiological basis behind such behavior, before attempting to psychoanalyze every bit of pawed turf you might encounter in your travels.

Recognize, for example, that the full scrape sequence involves three separate behavior patterns: scent-marking of overhead limbs, pawing of the ground, and urination in the pawed area. Furthermore, these separate behavior patterns may occur independently of each other, throughout the year.

Also, remember that a buck's scraping ability is determined by his level of physical, physiological, and behavioral maturity, as well as his reproductive condition, dominance status, and probably a lot of other factors we don't know much about. Highly dominant, mature bucks invariably do the best job of scraping. Regardless of their age, subordinates exhibit minimal scraping.

You may occasionally find some two and a half year old bucks that are avid scrape-makers — but only if they are physically and sexually advanced, as well as highly motivated in the absence of older bucks.

Even in the absence of older bucks, my research shows that one and one half year old bucks make only 15 percent as many scrapes as mature individuals. Some studies suggest that these young bucks make no scrapes at all.

Therefore, you will find little scraping activity in deer populations where sires are younger than three and one half years old. These young males also become sexually active later in the season than do mature individuals, exhibit less intense and delayed scraping behavior, and employ more of a seek-and-chase style of courtship.

The Overhead Limb

Suffice to say here, scent marking of overhead limbs probably serves as the primary means of communication among whitetail bucks throughout the year. Although some mature bucks may demonstrate the full scrape sequence during spring and early summer, most scent marking of overhead limbs doesn't involve pawing except during the autumn period.

The Georgia researchers observed that bucks of all social ranks (from very subordinate to the most dominant) commonly marked branches and inspected those that had been marked by other bucks.

Marchinton and his coworkers concluded the following: "The temporal distribution of overhead branch marking and the communal use of marking sites suggest that it communicates a buck's identity. In fall, scrapes were usually associated with branches that had been marked during the summer, but not all marked branches became scrape sites."

In other words, at least during the nonbreeding season, subordinate bucks do not avoid scent marks made by dominant individuals. They are actually attracted to them.

The overhead limb is a critical part of the full-fledged scrape. Take away the overhead limb at an active scrape and you'll virtually destroy the scrape. Conversely, add limbs in the right location and new scrapes will form where none previously existed.

Pawed Turf

Every pawed site is not a scrape, no more than every scent-marked limb becomes a scrape. Deer of both sexes, on occasion, paw the ground for many different reasons. Sometimes they even urinate into the exposed soil. But, it is my view that these pawed sites are not true "signposts", and should not be labeled "scrapes", unless an overhead scent-marked limb is present.

The communicative significance of pawing is unknown. Bucks commonly pawed the ground before or after an aggressive interaction, and sometimes even paw when approached by dogs or humans. Therefore, pawing seems to serve primarily as a threat display and show of dominance.

As part of the full scrape sequence, pawing is closely related to the buck's blood level of testosterone, which determines his aggressive mood and dominance. Subordinate bucks — those being psychologically suppressed and having low testosterone levels — seldom paw. Young bucks may visit and scent-mark limbs above active scrapes, but they rarely paw the site or urinate in the scrape.

Even the scientific community sometimes falsely categorizes scrape behavior. Reference made to doe scrapes, for example, probably is not justified. While does may paw the ground, and sometimes even urinate at the site, they've not been observed to scent mark limbs above the areas they paw. Hence, because they do not exhibit the full scrape sequence, such neurotic behavior probably should not be termed scraping.

Urination

Urination combined with squatting and rubbing the tarsal glands together — referred to as rub-urination — is also an important part of the full-fledged scrape. Dominant bucks commonly rub-urinate into their scrapes, leaving a distinctive musky odor.

Miller notes buck urine is much darker (at least during the rut) than that of doe urine, suggesting that it has a special composition. It is believed that urine deposited by the buck in the scrape relays information regarding his dominance, health status, and reproductive condition to other bucks and to does.

Primary Purposes

The complete scrape sequence probably serves two primary purposes: (1) they are an aggressive expression of dominance directed at other males, and (2) they allow the dominant buck to advertise his presence, superior status, and breeding condition to females.

Therefore, any given scrape might have an attractive, but suppressing effect, upon other bucks, but an attractive and stimulating effect upon does. Even so, there is no evidence that bucks purposely employ different scrapes to convey such contrasting messages.

Scrape Distribution

Scrapes are not randomly distributed. They are generally made along deer travel ways or clustered in areas of high deer activity, where they draw the most attention from other deer. But the area must have an open understory, the duff should be easily removed by pawing, and a suitable overhead limb must be present.

Although some hunters claim success hunting scrapes made along deer trails or travel lanes — categorized by some as secondary scrapes, but by others as primary scrapes — most writers suggest hunters ignore scrapes that are generally referred to as peripheral, boundary, territorial, or perimeter scrapes.

Since bucks are not territorial in the true sense of the term, no scrapes are made strictly as territory markers. In fact, all scrapes might be termed "communal" in nature, because all deer, regardless of sex or age, are attracted to them. Quite likely, however, those scrapes that draw no, or minimal, attention from other deer are not reworked.

Their Social Nature

Although bucks sometimes defend their scrapes against use by other bucks, subordinates generally are able to visit and scent mark overhead limbs, as long as they do not paw the sites or urinate at them.

There's a great deal we don't know about the sociability of adult bucks. However, socially compatible bucks probably travel freely through the dominant's breeding range, provided they behave themselves. In a high density deer herd, it's not unusual for a half dozen or more bucks to visit and scent mark limbs at an attractive scrape.

On the other hand, an outsider (especially a young disperser) might not enjoy such freedom, and might even be intimidated by such marks. He might more likely be driven off if the dominant discovered him at a scrape.

The Mythical Primary Scrape

I was amazed to find one well known outdoor writer describe in great deal how most "primary" scrapes are made where the doe deposits estrous urine. The writer failed to recognize, however, that a mature buck will make 50 to 80 percent of his scrapes before the first doe comes into estrus. And sometimes mature bucks will even scrape during spring, while neither bucks or does are in breeding condition.

For whatever reason, scrape reuse patterns vary greatly from one area to another. Some researchers have found fewer than 15 percent of the scrapes being reopened during the same season. But in my studies, 50 to 60 percent were reopened. Therefore, it's not surprising that some hunters place great importance upon locating the sometimes elusive, so-called "primary" scrape.

Outdoor writers seldom agree upon the definition of a primary scrape. Some consider any full-fledged scrape that shows frequent repawing as a primary scrape. Others reserve the term for highly reworked scrapes visited primarily by estrous does — also referred to as breeding scrapes. Still others claim that primary scrapes are special because trails form to them after the scrapes are made.

The most active scrapes, whatever you may wish to call them, are likely to be those located in the areas of greatest deer activity — provided the habitat is suitable for scraping.

There is plenty of evidence to indicate that adult does and fawns show interest in scrapes, and are in fact attracted to them. However, while following tame deer, University of Georgia researcher Timothy Sawyer found that does encountered scrapes by chance. Upon finding a scrape, the does frequently stopped to sniff the scrape, walked through it, or occasionally urinated near it.

It's important to note that related does tend to group and concentrate their activity in fairly small areas during the breeding season. Does tend to become very active during the rut, but generally in a relatively small area. Bucks, in turn, concentrate most of their scraping activity in such areas, not only to attract prospective mates, but also to warn competitive bucks. Also, remember that most intensive scraping activity precedes peak breeding, whereas peak scrape visitation coincides with peak breeding.

Chemical Signals

Moore and Marchinton reported that does commonly approached scrapes and urinated in them, leaving a strong scent trail leading away from the scrape. Upon returning to check his scrape, then, the buck was observed to make grunting sounds as he encountered the doe's scent trail. With his nose to the ground, the buck generally found the doe easily, within 200 yards of the scrape. In most cases the buck and doe associated only briefly.

Pheromones signaling a doe's estrous condition are contained in her vaginal secretions, and not her urine per se. When deposited along with urine, these chemical signals probably remain effect for only a brief period. In contrast, the doe carries with her the strongest attractive odors. Also, these odors might be detectable for 12 or more hours before she will stand for breeding. This gives the dominant buck plenty of time to locate the doe, even if it means chasing-off a more alert subordinant buck.

So in the majority of cases, a buck is probably already courting the doe before she has a chance to visit a scrape to signal her pending condition.

In some cases, however, if a buck is not close by when the doe approaches estrus, the doe then might wander in search of a mate. Then, conceivably, she would be highly attracted to any buck's scrapes she encountered. Such a happening might explain the observation reported by Moore and Marchinton, wherein the buck and doe bred over a mile away from the scrape where the doe's trail was initially encountered.

Mate Selection

Considering the personal nature of scrapes, and the fact that bucks tend to cluster scrapes where does concentrate their activity, the question then arises: Do female whitetails demonstrate mate selection by selectively visiting the scrapes made by males they prefer as mates?

In theory, the doe that "chooses" to mate with a large-bodied, large-antlered buck is selecting an individual possessing superior hereditary traits, thus assuring thrifty progeny and the perpetuation of genetic fitness within the herd.

To date, that question remains essentially unaswered. Obviously, however, in order for such a selective process to operate, the sexes must be able to communicate their identity, reproductive state, and certain other critical information. The female must be able to relate specific male odors detected at the buck's signposts to the individual buck himself.

Conclusions

If female whitetails do demonstrate some form of mate selection, then it seems that the scrape might be a good place for transfer of such information between the sexes. But don't forget that the dominant buck's scrapes also carry a strong message to all other bucks in the area: that he is "number one" and others had better act accordingly. Given our current understanding of such things, it appears that any "hot" scrape adequately addresses both needs.n

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07 - 22 - 17
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