A Scientific Look At…RATTLING

When I started deer hunting, nearly 60 years ago, my dad taught me to sit quietly. Back then, I couldn’t even imagine creating a commotion by bagging 2 pieces of bone together. And, I don’t mind admitting, I have yet to kill my first buck using the antler rattling technique in Upper Michigan, where forest cover is dense, deer populations are low, and mature bucks are not overly abundant.

The practice of antler rattling to attract whitetail bucks, by simulating buck sparring and fighting, apparently started in Texas during the early 1970s. Currently, it is widely used, presumably successfully, wherever deer are fairly abundant and populations have a reasonable adult sex ratio and buck age structure.

The popular literature abounds with stories of antler rattling success; and so does advice relative to when and how to rattle in a big buck. Any hunter/writer who has drawn a buck into killing range via antler rattling immediately becomes a self-proclaimed deer calling expert, or so it seems. Unfortunately, antler rattling advice varies a great deal from one expert to the next. Scientific study of the subject appears quite limited.

Sparring vs. Fighting

Antlers are unique structures found only among members of the deer family, Cervidae. They evolved hand-in-hand with certain aspects of breeding behavior.

Initially, soon after antler velvet stripping, bucks engage in “skill sparring.” In skill sparring, a buck gains knowledge of the size of his antlers and how they relate to those of other bucks. They merely click their antlers together with minimal pushing and shoving. Even large-antlered bucks might tolerate such contact with smaller, younger bucks.

“Demonstrative sparring” is different. Even a friendly match of skill sparring might turn into a more decisive bout of demonstrative sparring. The purpose of these more serious encounters is to assess and establish social rank prior to the rut. Bucks push with all their might. This is a true test of physical strength. There is always a winner and a loser.

Violent “dominance fighting” is less common. True fights can lead to serious injury and even death. Such aggressive interactions tend to be brief and situational in nature. Usually, they occur only among evenly matched prime-aged bucks during the rut, often in competition for an estrous female.

Generally, more fighting occurs when deer are abundant, when the adult sex ratio is closely balanced, and when a high proportion of bucks are 3.5 years or older. Combatants need not be strangers, and serious fighting might erupt anytime during the breeding season, while male testosterone levels are high.

Logically, antler rattling is employed in hopes that it sounds like the real thing (i.e., 2 bucks sparring socially or fighting over possession of an estrous female) and results in attracting an inquisitive buck into killing range.

The Study

Despite considerable study of whitetail breeding behavior, few studies have documented the effectiveness of antler rattling to attract bucks. In fact, I can find only one published scientific account designed to evaluate the role of antler rattling as a deer hunting technique.

Researchers from the Universities of Texas A&M and Georgia, led by Mickey Hellickson and Karl Miller, respectively, conducted two experiments to test whitetail buck response to antler rattling in Texas.

During one experiment, conducted on the Welder Wildlife Refuge from 1992 to 1995, researchers determined buck response to 4 rattling sequences that varied in duration and loudness.

Generally, the observer was situated in an observation tower, while another performed the rattling upwind from a clump of brush.

Rattling sessions were performed during pre-rut, rut, and post-rut. All rut rattling sessions were conducted within one week of mean conception dates for the area (22 November). Pre-rut and post-rut were then set as the one-month periods 15-45 days before and after the mean conception date. Responding bucks were videotaped and their ages were estimated by the observer.

A total of 171 rattling sessions resulted in attracting 111 bucks, 48 (43 percent) of which were observed at ground level.

The second experiment was conducted on the Faith Ranch, where researchers had previously attached activity-sensing radio transmitters to 48 bucks. Mean conception date for deer on the ranch was about a month later (24 December) as compared to that for deer on the Welder Refuge.

Radio-located bucks were approached to within 200 meters (downwind) before rattling. Then, each buck’s response to rattling was monitored by telemetry. In all, 33 rattling sessions were performed near 18 radio-equipped bucks. If the radio signal indicated movement and became stronger, the buck was classified as having responded.

Seasonal Response

In both experiments, total buck response to rattling was greatest during the rut and lowest during pre-rut. However, seasonal response rates varied according to buck age. That is, young bucks (1.5 and 2.5 years) were most responsive to rattling during the pre-rut period, whereas middle-aged bucks (3.5 and 4.5 years) more frequently responded during the rut.

Mature bucks (5.5 years and older) were slightly less responsive during peak-rut, possibly because they were already tending estrous females.

During post-rut, most young and middle-aged bucks had returned to traveling in bachelor groups. However, mature males were still testing females. These single, mature males represented the majority of responses to rattling during the post-rut.

This trend is undoubtedly related to seasonal variations in testosterone levels and mating opportunities. Peak sex hormone levels, which are achieved during the rut, contribute to increased fighting among older bucks. Logically, rattling is especially attractive to older bucks because it mimics competition for an estrous female.

The researchers found that single males observed from towers usually responded to rattling – “possibly because dominant males were not in the immediate area to discourage subordinates.”

On the other hand, young bucks probably are less likely to become involved in serious fights.

Conversely, increased sparring during the pre-rut and post-rut is associated with lower levels of testosterone. Also, bucks are more inclined to associate and travel in bachelor groups before and after the rut, increasing the likelihood of their coming into friendly antler contact.

Loudness-Duration

All antler rattling sessions were 30 minutes in length and involved 3 10-minute segments. But each session varied in loudness and duration. For example, short and loud sequences involved 1 minute of loud rattling, followed by 9 minutes of silence. A long and loud sequence involved 3 minutes of loud rattling, followed by 7 minutes of silence. Bouts of low volume rattling, that mimic sparring, followed a similar pattern.

In addition, before rattling began, the individual doing the rattling broke nearby branches, rubbed trees, and scraped the ground to simulate bucks fighting.

Of the 4 antler rattling sequences tested, those 2 involving loud rattling attracted the most bucks. In fact, 73 percent of buck responses were to a loud sequence. Duration of rattling (1 versus 3 minutes) did not influence buck response to loud rattling. In other words, bucks were most responsive to rattling that mimic fighting, whereas they were less likely to investigate rattling that sounded like sparring.

During loud rattling sessions, bucks were most responsive during the first of 3 rattling segments. By comparison, bucks were more likely to respond to the second segment of low volume rattling.

Bucks not only responded more frequently to loud rattling, they were quicker to respond and seemed more aggressive when they approached. Because of the locally high buck density, the researchers speculate that bucks become accustomed to the frequent sound of sparring and therefore are less likely to investigate low volume rattling.

Other Factors

With few exceptions, rattling during the morning hours (7:30AM until 10:30AM) was most productive. However, long and loud rattling produced significantly better results during the afternoon hours (1:30PM until 4:30PM). But keep in mind, even midday rattling can be effective.

The researchers found no relationship between buck response to rattling and temperature. However, probably as expected, buck response rates were highest when winds were light and decreased as wind speeds increased.

Most (60 percent) bucks that responded to rattling were first sighted downwind. This seemed to suggest that bucks used wind direction to determine the location and/or source of rattling, and even maneuvered from other positions to approach from downwind.

Based on observations of radio-collared animals, bucks apparently did not learn to avoid antler rattling. In 13 of 14 rattling instances, individual bucks responded to successive rattling sessions. One buck responded on all 4 occasions that a rattling session was performed nearby.

Conclusions

Many so-called deer antler rattling experts recommend going through a multitude of unnecessary gyrations, such as first “tickling” the antlers together gently, in order to attract a buck. The research discussed here indicates that’s a bunch of bull — the whole process is really quite simple.

If you hope to attract a decent buck into killing range via antler rattling, the quickest and best way is to bang the damned bones together good and hard for about a minute during the rut.

On the other hand, since mature dominant bucks are probably tending does during peak-rut, the best time to attract a monster buck might be during early-rut, late-rut, or even post-rut.

If you can’t lure a buck into view, within 20 to 30 minutes, following 1 minute of loud rattling, your chances of success probably will dwindle with time. Then, you’re better off trying another spot. Surprisingly, even older bucks apparently do not learn to avoid rattling.

Certainly, this study is not the last word on how to rattle in a big buck — which the researchers acknowledge. Obviously, the chances of success decline with decreasing deer population density and poor sex-age structure, and will likely depend upon visibility as well as other unknown factors. But under the right conditions antler rattling can be very effective.

Will antler rattling work in your area — or mine? I don’t really know. But after reading this report, I’m gonna give it a darn good try.