Mineral block bucks from yearling to 5-1/2 year-old from a calcium poor area in Northern Minnesota.

Back in 1970 I often wondered if a lack of adequate calcium and phosphorus might be the reason so many yearling bucks in my original Minnesota whitetail study area were spike bucks, about two for every forkie. To find out, I placed four cattle-type mineral blocks in the western half about the first of May that year, the beginning of the antler growing season, That fall the numbers were reversed, two out of three yearling bucks were forkies or better (one even an eight-pointer with a nine inch spread). Then wondering if mineral blocks could increase the size if antlers grown by older bucks in my low-calcium study area, I continued setting out blocks every spring for 19 years and compared masses of antlers of bucks of same ages taken in the treated half with antlers of bucks taken in the untreated half every year. I did this by filling a large pot to the brim with water placed in a larger pan, submerging the antlers in the water and then measured the amount of water that overflowed into the pan. Antlers from the treated half averaged about 10–20% greater in mass than antlers from the untreated half. Moreover, numbers of surviving fawns (in wolf country) in early November throughout the following 18 years were always about 10– 20% greater in the treated half. Convinced of the benefits of mineral blocks, capable of enabling some bucks with 150–inch antlers (Boone and Crockett measuring system) to grow 170 or 180–inch antlers, my sons and I have been placing mineral blocks throughout my second primary study area every spring since 1990. Though we have not continued comparing antler sizes since then, the number of bucks worthy of being mounted taken by my sons, daughters, grandsons and I since 1990 is eight times greater taken than the number taken by an equal number of my family, including uncles and cousins, between 1945 and 1989.

In recent years sporting goods stores have become filled with a great number of products claimed to enable bucks to grow larger antlers, some in liquid form and powder form and some even being seeds. Last spring my son John and I decided to try a different, less expensive brand of mineral blocks claimed to grow larger antlers. When we checked them while scouting last October, they were gone, and judging by the lack of hoof prints and wear around the sites where they were placed, they were gone well before the antler growing season ended (growth ends about the first of September). This was strange because the more expensive blocks we had traditionally used always lasted 2–3 years. From now on, we decided, we’ll stick to using what we know works: our usual $12.95 much-more-durable cattle type 40–50 pound mineral blocks with the top two listed ingredients being calcium and phosphorus (the primary ingredients of bones and antlers) followed by a trace of needed zinc, a trace of unneeded salt and vitamins.

We place our blocks on exposed roots of mature evergreen trees where well hidden by surrounding cover. A mature evergreen protects the blocks from rain, making them last longer. The surrounding cover keeps them from discovered by other hunters who might decide they’ve discovered a great stand site. Actually, mineral blocks are very poor stand sites. Neither bucks nor does are much interested in mineral blocks during hunting seasons because by then antlers of bucks are fully grown and fawns of does are fully weaned. Wherever mineral blocks are placed, 4-6 deer of the near vicinity will quickly find them and create beaten paths leading to them from several directions.

To get the desired antler growth, the blocks should be placed within or near bedding areas of mature bucks. The reason is, while growing antlers, older bucks tend to be recluses, bedding, watering and feeding in or near their secluded, difficult-to-find hideaways only 1–2 acres in size. While scouting in search of them, look for plenty of fresh and old tracks 3-1/2 to 4 inches long, fresh and old droppings 5/8 to 1-1/4 inch long, beds in deep grass 45 to 56 inches long and clusters of six or more antler rubs on tree trunks 2–4 inches or more in diameter — characteristic signs of bedding areas of mature bucks. Where you find plenty of fresh mature buck sized tracks and droppings, you are probably close enough, especially if near water. We typically place 2–4 blocks in or near buck bedding areas per square-mile.

My sons tote mineral blocks with their hands. I prefer carrying one block in a large plastic bag in a packsack attached to a heavy-duty pack frame along with 2–3 bottles of water and much-needed insect and tick repellent or two blocks tied down on a plastic toboggan. It’s now mid-April, an ideal time to take care of this chore. Early May is okay.

By the end of a day of scouting and dropping off mineral blocks, my sons and I are usually weary and hungry but grinning, anxious to share our findings over a meal at a lakeside resort on the way home. Our grinning reveals we have each found some fresh tracks in the 4-inch range, fresh droppings 7/8-inch or more in length, antler rubs on tree trunks 4 inches or more in diameter (rubs made during the previous fall) and/or beds 50–56 inches in length — signs only made by trophy class bucks. Following this particular day in spring, fall can never come quickly enough.

An afterthought: since whitetails can’t be kept from congregating in wintering areas in winter, I have often wondered if a drug could be added to mineral blocks that can kill parasites such as brain worms in deer and moose, not fatal to whitetails but sometimes fatal to moose. After researching this, my son John recommends the tapeworm dewormer Praziquantel as an example. Similarly, I wonder if adding a proper drug could be a way to eliminate chronic wasting disease in whitetails.

Nine deer in a wintering area. (Note the one laying down in the upper left.) Later, when I find it, I will add a photo of a forky attacking an older, dominant — but antler less — buck.

Since 1970 when I first began studying habits and behavior of wild whitetails in northern Minnesota, I have always been astonished by their sudden, overnight disappearance in late December, their recently made antler rubs and aging tracks in snow mute evidence of their once great numbers and activities. It usually happens about December 22nd, plus or minus a few days, depending on snow depths and weather. Following a three-foot snowfall that began on Halloween in 1992, this happened much earlier. This annual disappearance is due to their annual migration to better places to survive winter. Such places are commonly called “deer yards.” I prefer to call them “wintering areas.” They are generally traditional in location for different populations of deer. They provide varying numbers of whitetails with superior cover from frigid winds and precipitation and adequate quantities of winter foods — woody browse or crop residues — until snow melt in early spring. Some wintering areas are small, shared by as few as two-dozen deer, and some are huge, shared by hundreds. Many whitetails, trailed by fawns making the trip for the first time, migrate as far as 20–30 miles to reach their winter destinations. Once there, though they feed together within the wintering area or in areas surrounding them, does and their young, fawns and yearlings, bed together in one or more areas and bucks 2-1/2 years of age and older (bachelor groups) bed together in separate areas.

While in wintering areas, it is very difficult to get near whitetails (within easy shooting range for late season archers or muzzleloader hunters) without being seen, heard or scented. All it takes is a series of snorts that starts with one to warn the entire population within seconds. Extreme care must be taken, using dense intervening cover or terrain downwind or crosswind to hide your approach to a stand site near a well-used deer trail within or adjacent to a wintering area feeding area. Appropriate winter camo clothing is also important. Keep in mind, with all those unseen whitetail eyes, ears and noses often pointed in your direction, odds for success at one stand site are certain to be short-lived.

Another change common to the same late days of December is shedding of antlers by many (not all) of the largest of bucks, typically dominant breeding bucks. I don’t know if early shedding reflects the diminished health of these bucks in consequent of the great demands on their bodies throughout the previous four months or because bucks destined to be most dominant are somehow on a earlier schedule of photoperiodism and/or hormonal changes. At any rate, sometime in December the blood flow to the very strong connective tissues that attach antlers to skulls of older bucks shuts down, these tissues begin to deteriorate and then the antlers drop off, usually around December 22nd, plus or minus a few days. Progressively younger bucks shed their antlers progressively later, yearling bucks typically last, well into April.

There are therefore three reasons why the odds of taking a whitetail buck with enormous antlers in in late December might not be favorable: 1) they are absent from your usual hunting area, 2) they are well protected by great numbers of deer in their wintering areas and 3) they might not have antlers.

I have to find the photo.

After my wife Jene and I saw a big 10-point dominant buck drop both of its antlers on December 22nd in a Minnesota wintering area in 1984, she and I and that buck were then equally surprised to see a fork-horned yearling buck suddenly lower it head and attack the big buck (see photo), likely taking revenge for all the times it was quickly vanquished by that buck during the previous months. With an obvious look if disbelief, the big buck had no choice but to retreat with all possible speed.

Upon shedding antlers, even the most aggressive of bucks will suddenly become docile. It is said bucks can no longer produce sperm and father young after this happens, but it’s more likely, I believe, because they can no longer compete with antlered bucks for opportunities to breed.

The usual 5% of does (about one mature doe in 18) not yet bred by this time will again begin to experience estrus (heat) for the third and final time in a wintering area during the last few days of December. Estrus in does no longer occurs after this two-week period because before another 28 days passes, the ratio of darkness to sunlight necessary to trigger estrus in does no longer exists (it has changed significantly).

A killer buck with part of his harem. This Wisconsin buck killed a larger 10-pointer.

Jene and I regularly photographed two Wisconsin does (in widely separated areas) that were always in heat and always accompanied by dangerous-acting dominant breeding bucks on January 1st. One of these bucks killed a shadowing 10-pointer the evening after we photographed them. The fiercest of battles between large bucks, especially between equally matched dominant breeding bucks fighting for the opportunity to breed the same doe in heat, generally occur during the three separate ywo-week breeding periods. An opportunity to take advantage of the one day of unusual vulnerability of a dominant breeding buck accompanying of a doe in heat is very limited during the final few days of the year, of course, though not impossible, weather permitting.

Weather in December can be brutal for whitetails and whitetail hunters alike. Under severe conditions, whitetails are likely to remain bedded throughout hours they normally feed, temporarily living on fat stores. Weather in December can also be a boon for late season whitetail hunters. Following a spell of very cold weather, a thaw or near-thaw with the wind calm to light will trigger a flurry of whitetail feeding midday. For a couple of hours every whitetail in the woods will be on the move. Keep track of weather forecasts. Whenever a midday thaw or near thaw is predicted, be at a stand site adjacent to a forest browse area or a farm field with crop residues that have been attracting deer with lots of fresh tracks of walking deer between 10 AM and 3 PM for one the year’s very best opportunities to take a deer.

This is it: the end of whitetail rut. After about the 9th of January until about September 1st a whitetail buck’s calendar is bare.