With the whitetail deer, glandular secretions and scent-marking play a more important role in communication than do visual signals
and vacalizations. The latter serve only immediate, short-range purposes, whereas scent-marks serve as an extension of the animal
itself, and remain functional long after the maker has left the area.
Mature whitetail bucks scent-mark vegetation year round, usually in a subtle manner which is difficult to detect. During autumn,
however, they establish highly visible signposts, known as buck rubs and scrapes. The hunter who can learn to interpret these
signs will add to their chances of success.
Few bucks rubs are made while removing antler velvet, a process normally complete within 24 hours. Instead most rubs are made
by few dominant bucks to advertise their superior social rank, allowing them to signal their readiness to breed and proclaim
dominance in a given area.
Signpost rubs are eye-catching, and they are annoited with the maker's distinct odor. All whitetails possess specialized forehead
skin glands that become very active during the rut, but tests indicate mature, socially-high ranking bucks exude greater amounts of
the glandular secretion as compared to younger males and females. Because rubbing is done with the antler base and forehead,
each rub carries the distinctive identifying odor of the maker.
While prime-age, dominant bucks are the primary signpost makers and message senders, young males and females are attracted
to the signposts and are the primary message readers.
The chemical signals exchanged tend to suppress the aggressiveness and sex drive of young males, but stimulate females and
help synchronize breeding. As a result, the presence of older bucks and their signposts help maintain social order.
When in the mood bucks will rub just about anything, including fence posts, and powerline poles. Given a choice, however, they
prefer to rub trees and shrubs, one-half to four inches in diameter, with smooth bark and no lower limbs. They generally avoid those
with low limbs and warty bark.
In the southeastern United States, bucks seem to prefer aromatic species, such as cedars and sassafrass but readily rub alders,
cherries, eastern juniper, witch hazel, winged sumac, sourwood, striped maple, and pines.
Trembling aspen is the most highly preferred species for rubbing in the Northeast and Upper Great Lakes region. In the smaller size
classes, it has smooth soft bark that is easily stripped, and the inner wood is light colored, with long lasting brillance once
exposed. Staghorn sumac, red maple, black cherry, balsam fir, pines and willows are also frequently rubbed, whereas sugar maple,
ironwood, beech and paper birch are usually avoided.
All bucks occasionally rub stems smaller than two inches in diameter, whearas only older bucks normally rub trees six or more
inches in diameter. In addition, young bucks seldom rerub the same stem. So, large diameter trees that show frequent rubbing are
a sure sign that older, rut-experienced bucks are in the area.
The timing of velvet shedding, and subsequent rubbing, is triggered by the shortening day length in autumn. Aside from a more
prolonged velvet shedding season found in southern bucks, despite the north's early rut, peak velvet shedding dates normally vary
by only a few weeks throughout the United States.
On northern range, bucks generally rub off velvet during lat August or early September, nearly two months before the first does
breed. Some yearling bucks and unhealthy older individuals are delayed by several weeks. In the south, expect mature bucks to
strip velvet in the middle of September.
Mature dominant bucks maintain year-round supremacy over their peers and conrol a stable male society within a given area. They
began marking their domain sonne after shedding velvet, without much prior combat or testing, and continue marking until they cast
their antlers. Therefore, serious signpost rubbing in September is evidence of a big buck's presence.
By comparison, yearling and 2-1/2 yr old bucks have little status or rank to advertise. They also enter rutting conditions later than
older males. Even in the absence of mature bucks, yearling bucks only make about half as many total rubs as prime age animals
and show minimal rubbing activity until late October. Such delayed and low level rubbing is characteristic where antlered males are
heavily harvested and few survive to maturity.
The amount of rubbing a buck does will depend upon his blood levels of the male sex hormone testosterone, which in turn hinge
upon his age and dominance status. Prime-age bucks are the first to reach the threshold levels of testosterone that cause velvet
shedding. They also achieve higher concentrations of the hormone, which contribute to their extreme aggressiveness, attainment of
higher social rank and tendency to make more rubs.
Rub densities in any given area will depend upon many factors. Research shows rub densities even change from year to year,
depending upon the nutrional status of the herd.
On good deer range, buck-rub densities may vary from a couple hundred to nearly 1000 per square mile, and will be closely related
to the number of older bucks in the population. A fairly large number of young bucks may make relatively few total rubs, as
compared to only a couple of older bucks in the same area.
Soon after "rubbing out", a dominant buck shifts his center of activity to interact with other deer over a breeding range of anywhere
from one to five square miles. Bucks on northern range tend to travel a large autumn range when deer density is low. In the South,
they're more apt to cover less area, especially where deer are plentiful.
Clusters of buck rubs are most likely to occur close to areas with abundant autumn food. This could be wooded cover near corn or
alfafa fields, oak habitat when acorns are abundant, adjacent to forest openings, or near artifical feeders and food plots. Such a
rubbing strategy makes good sense, of course, because other deer would also likely concentrate near such choice feeding sites,
making the buck's signposting most effective.
Also look for rubs along travel corridors such as deer trails, ridge tops, old logging roads, and in swales at stream crossings.
Clusters of rubs in secluded patches of heavy cover may also reveal the favored bedding location of older bucks. Stand hunting
along travel corridors, between bedding and feeding locations, will generally prove the most successful.
The presence of mature bucks and the availability of favorable rubbing stems are primary factors determining buck-rub density in
any given area. In fact, some reseachers speculate that clumbing of rubs is primarily related to location of preferred stems.
Therefore, a scarcity of buck rubs sometimes may be due to a scarcity of preferred rubbing stems, not the scarcity of older bucks.
Article written by John J Ozoga
Pulished in Woods-N-Water News Michigan's Premier Outdoor Publication November 1999 Issue
