Whitetail NEWS

Drought years can affect antler development. PowerPlant is one product that can provide high-quality forage during dry periods.

There are literally hundreds of articles written annually about the effect of age, genetics and food on whitetail antler development. Because of their importance, these three factors are commonly identified as being the “building blocks” of quality deer management.

While hunters often have different opinions, many biologists highlight quality nutrition the key element, since without it, deer will not achieve their full potential regardless of age or genetic potential. A study of the various national record books seems to validate their point. Today a vast majority of the mega-bucks killed annually come from agricultural regions, where food is plentiful and more nutritious. But even in these regions, other factors may come into play in regard to trophy potential.

I was born and raised on a farm in the Ozark Mountains of northwestern Arkansas . As a farm kid, I quickly came to understand fully the effects rainfall can have on crops, from the hay meadows to the corn fields. In years of drought everything suffered, and the paycheck at the end of the rainbow was often far smaller.

In that same vein, common sense (which is the farmer’s mentality) tells us that all livestock, from sheep to cattle, will be far healthier when the forage they consume is in prime condition. This principle also applies to deer. Thus it follows that without adequate moisture, the various forages don’t grow as well, their quality is poorer and the animals that feed on them will not gain as much weight. When plants have adequate moisture, they provide a higher quality food source, the animals will feed more (lush forage tends to taste better) and they will also be able to more efficiently convert that food into muscle, fat and bone.

From this it would seem obvious that the amount of rainfall in any given area─ at least somewhat in correlation with the period during which that rainfall occurs─ could have a direct effect on the size of a buck’s headgear, which is a form of bone.

Clayton Wolf, deer program leader for the Texas Parks & Wildlife Department (TPWD), acknowledged that statement when he recently observed that “timely spring rains resulted in range conditions that helped jump-start antler development. Hunters (in 2003) are seeing significant increases in antler mass of older bucks.”

Wolf went on to say that in 2002 “although rains came late in the summer (of 2002), apparently the deer did a heck of a job of catching up. The rain was so late that we anticipated it wouldn't help, but guys were seeing some pretty decent deer.”

Keep those two statements, made by a professional in the field, in mind as we explore further.

I’ve often wondered about the effects rainfall has on antler growth. So I recently set out to see if there was any direct correlation between the amount of rainfall which falls at specific times, and the antler size of bucks harvested the following fall.

On the face of it, I really didn’t think the project would be that difficult with the power of the Internet at my disposal. But oddly, in a day and time when raising whitetails is big business, I could find virtually nothing written about the topic, even within such notable volumes as Antler Development in Cervidar by Robert Brown; and Whitetail Deer – Ecology and Management, the absolute “bible” of wildlife personnel nationwide. Each of these offered little more than passing mention of the topic. There were many dissertations about the effects DROUGHT could have on body and antler size, but little about the more-or-less opposite of that extreme. As nearly as I could determine, no one has ever done formal research on the topic here in Arkansas , or in the entire southern United States .

So as the old Star Trek series proclaimed, I set out “to boldly go where no man had gone before.” The deeper I dug, the more aware I became that the common sense approach would have to do.

WHEN rainfall occurs is an important and often overlooked factor where antler development is concerned. Rainfall in the fall and winter, after antler growing is complete, can have no effect on the current season, and only limited effect on the next, that being the carryover in ground moisture which increases plant growth during the following spring.

That concept is termed the “lag effect.” It simply means that if a buck enters the primary antler-growth period in good shape, the chances increase of him producing a better rack that year. For example, in the national forests of the Ozark Mountains , bucks should carry better headgear in years after a heavy mast crop the preceding fall.

However, the primary period we will be concerned with here is the actual antler─ growing season (approximately March through July); and the time frame I term as being the antler─ completion period (August through early September).

The one meaningful study I was able to locate took place down in Texas back in the 1980s. Gordon Whittington, the editor of North American Whitetail Magazine, utilized the results of this particular work in an article he wrote years ago concerning rainfall and antler production in the Lone Star State .

A Texas landowner named Stuart Stedman, who raised whitetails on his vast acreages, worked with researchers from the Ceasar Kleberg Institute in Kingsville , Texas . Beginning in 1986, helicopters were used to herd deer into catch nets, where workers weighed, measured and tagged them.

As part of this study, each year from 1986 through 1990, a total of 50 bucks were captured annually. It should be mentioned that these animals were acquired at random but always from the same general area, somewhat neutralizing the effects different plant/food sources could have on antler development. For this part of the study the researchers concentrated on mature bucks, those five years old or older, carefully taking their antler measurements using guidelines of the scoring system of the Boone & Crockett Club (B&C).

Just a note: at first it seemed to me that the test could be flawed because different bucks were captured from year to year. Maybe those caught one year were merely larger than those of the previous year because of differing age structure. But I realized that if they had used the same bucks year after year, growth due to age would have tainted the results. Either way, wildlife research is seldom a finite science.

The first thing that became apparent to the researchers was that the average scores of the bucks’ racks fluctuated widely from year to year. In 1986, the first year of the study, the mature buck average score was 128. That total jumped to 136 in 1987; fell to 128 in 1988; fell even more to 124 in 1999; before finally reaching a peak of 139 in 1990.

Stedman himself surmised that the amount of rainfall during the March-April period was the variable, and also the most likely factor. Upon checking, he found that in 1989, which was the year with the lowest rack size, that area received only 7.65 inches of rain from March 1-August 31. That total was well below the average for the area; and of particular interest, only .9 inches of that total fell in March and April (the beginning antler-growth months).

But the following year, during which the scores were the highest, 10.88 inches fell in that same March 1-August 31 period. Even more importantly, if you agree with Stedman's correlation, 6.01 inches, an abnormally high amount, fell in March and April. During 1987, the year with the second-highest scores, rainfall was 3.70 inches during the March-April period – again well above the two-month average for the area.

So there you have one scenario where the amount of rainfall during a particular period could have a direct effect on rack size that following fall. Ample and nutritious food intake during the primary antler growth period, increased by the wetter conditions, should improve all bone growth. Common sense.

Now for the second time span I alluded to earlier ─ the August-September antler─ completion period.

Today at least some biologists believe that the amount of rainfall during the late summer/early fall period also can have a direct effect on rack size. They base that premise on the fact that during the primary antler growth period a vast majority of the nutrients taken in go toward tissue and skeletal growth. Only after bodily needs are completed does the headgear receive preference.

Maximum body growth is typically attained around the first of August. That means that the availability and nutritional content of food taken in after that point should have a direct bearing on final antler size. Thus in wetter years, when the moisture level in the ground is higher via summer rains, antlers would/should be larger. Conversely, in the years when everything is pretty well dried up by mid-August, racks would suffer. Does this theory have merit? You be the judge.

Since Arkansas is the state I'm most familiar with, and since correlating rainfall amounts for a brief 45-day-or-so period with antler size in other states turned out to be a virtually impossible task, I'll use deer taken here in the Natural State for my hypothesis.

During the decade of the 1990s, the Natural State had two truly wet years, 1992 and 1996; and in both of those years rainfall was unusually heavy during the late-summer period. As a result, grasses and other forms of ground cover were still green and growing well into October. Temperatures were also moderate for the same periods, and many trees had buds popping out up until the first frost, which occurred in mid-November. Other than those two instances, conditions in Arkansas were typically southern-dry during the hot months.

In 1992 there were six Arkansas bucks killed large enough to make the Boone & Crockett Club all-time record book. That was an increase of four over 1991, a dryer year, and was until that time the most ever taken here in a single season. Then, in 1996, there were eight book bucks taken. In no other year during the decade were more than four killed.

In addition, there are currently 568 deer listed in the Arkansas Trophy Club, which requires a minimum score of 150 for typicals and 175 for non-typicals using the B&C scoring system. Of those deer, 291 were killed in the 1990s, an average of slightly more than 29 per year.

But in 1992 a total of 41 Trophy Club deer were taken, and in 1996 that total rose to 53! Only one other year, 1999, recorded more than the average (36).

Furthermore, 2001 was an exceptionally dry year. Only two bucks killed in Arkansas were large enough to the make the B&C books, and only 17 made the state record books.

Are those finite results? Certainly not. But no study I've ever read (and I've read a lot) can make that statement either. Common sense dictates that something unusual took place in 1992 and 1996, and rainfall during the late summer period is the variable in both cases.

In fairness, it should be pointed out here that there are numerous other factors which could have an effect on the number of bigger deer taken in any given season, particularly:

- Hunters tend to move more quietly when the ground is wet, increasing their chances.

- Hot weather/dry conditions and hunting don't mix, so there will be fewer hunters in the woods during dryer times.

- Deer also tend to move less, at least during daylight hours, when the woods are dry/noisy.

- Rut activity will also be more confined to the cooler early and late hours during hot weather.

All of these would certainly have an effect on bigger buck harvest totals. But based on my evidence, I would have to say that there is at least some positive correlation between growth period rainfall and trophy production. And I'm also willing to bet that at some point in the near future you will see a study targeting this idea.

Should your management program completely reliable on Mother Nature every spring and summer? Not exactly.

There are insurance policies you can purchase each year to minimize the effects of drought years (and to increase quality forage during wet years as well). The most effective insurance programs are known as the PowerPlant and Extreme policies.

Both products, although very different, provide two crucial elements: high protein and high drought resistance. PowerPlant, an annual, can be grown in most regions where rainfall is 3 or more inches per month during the late spring and early summer. After maturation, PowerPlant can literally survive on an inch of rain per month. It is a great product for providing protein-rich forage during the end of the summer.

Extreme, a perennial, can also be grown throughout the country. Extreme is even more adaptable than PowerPlant, as it requires even less rainfall for lush growth.

So keep these food plot products in mind next spring. They can certainly help you maximize your bucks’ antler potential by reducing the effects of low rainfall amounts.