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Responsible Whitetail Deer Management

A Deer Management Article

Written by T.R. Michels


More and more whitetail hunters are interested in hunting for trophy animals. But, because game managers are often interested in providing a large, healthy, balanced herd, and not necessarily trophy animals, these hunters are taking it upon themselves to try to increase their chances of seeing a trophy by improving the habitat and practicing quality management, with the emphasis on growing trophies. The hunter who is only interested in helping the animals grow bigger racks by providing food plots, minerals and limiting his hunting to larger racked animals often unwittingly improves the quality of the entire herd. Not only will the bucks use the food and minerals, but so will the does and fawns. If the hunter then passes up smaller animals he gives them a chance to mature, develop fully and contribute to the gene pool.

Management Practices
There is no question that deer herds must be managed. Increasing human populations, urban sprawl and changing land practices have led to less available deer habitat while deer herds have continued to increase, which has led to an overpopulation of deer in many areas. This has compelled wildlife managers to issue abundant doe permits each year in order to keep the deer herds within the carrying capacity of the available habitat. The deer management practices of many wildlife agencies revolve around the need to balance the deer herds in relation to the habitat while still trying to keep deer populations high enough for hunting, with hunting as the primary method of deer reduction. The current practice of keeping deer populations high enough that they can be hunted, and the past management practice of bucks only hunting, combined with the belief by many hunters that they should only shoot bucks if they want to keep deer numbers high, is precisely the reason why there are too many deer, particularly does.

It is usually too many does, not too many bucks in a deer herd, that prompts game managers to issue numerous doe permits in the hopes that enough deer will be removed to keep their numbers at acceptable levels. Eventually this becomes a vicious cycle and both the deer and the habitat suffer. The effects of this cycle generally result in low buck:doe ratios and fewer numbers of dominant breeding bucks, which leads to breeding periods that are later, and longer, than they should be, resulting in poor spring survival rates of fawns.

To add to the problem of too many deer, but not enough bucks, the interest in trophy hunting for white-tailed deer has skyrocketed in the past few years. This interest in high scoring whitetail racks by numerous hunters puts added pressure on the already depleted number of large antlered animals, and further reduces the number of available older dominant breeding bucks. Fewer numbers of bucks, particularly older dominants, result in fewer contacts between the does and the priming pheromones deposited by bucks at rubs and scrapes. These priming pheromones are thought to cause the does to come into estrus and help synchronize the rut activity between the does and the bucks. When these pheromones are absent the does may come into estrus from as early as mid-October to as late as January.

In a deer management study by Larry Marchinton between 1981 and 1986, an increase in the buck to doe ratio from 25:100 in 1981-82, to 54:100 in 1983-84 resulted in the average breeding date changing from November 11 in 1981 to October 15 in 1982, almost a month earlier than normal, and the length of the breeding period was shortened from 96 to 43 days. In another study using quality management techniques, the average breeding date occurred almost two months earlier.

As a result of these studies it is now believed that the peak of the rut, or peak breeding period, of white-tailed deer could normally occur during mid-October in some southern areas.

During Marchinton's quality management study the average number of fetuses per does over the age of 2 1/2 years increased from 1.6 in 1985 to 1.9 in 1986, and pregnancy in doe fawns was detected in 1985. Fetal male:female sex ratios shifted from 64:36 during 1981-83, to a more balanced 47:53 during 1984-86. The average weights of yearling bucks increased from 90 pounds in 1982 to 110.5 pounds during the 1983-86 portion of the study. There was a significant weight increase in the 3.5 year and older bucks in a similar study by McKelvy. The positive results of these studies were credited to the increased age structure of the bucks.

An increase in the number of older dominant bucks also has a direct suppressing effect on the testosterone levels of younger bucks, which reduces their aggressiveness and competition for breeding privileges. Since a low position in the breeding hierarchy results in less reproductive behavior and lower weight loss, those young bucks that do not breed grow to greater body size before they become dominant. This results in an overall increase in the number of older dominant bucks which leads to earlier fawning dates and heavier body sizes of yearling bucks, and this leads to higher survival rates and eventually to increased buck numbers.

If both game managers and hunters can agree to reduce the number of does and let the younger bucks grow, while still keeping the herds balanced and within the carrying capacity of the habitat, there will be an increase in the number of older bucks. There is also a good probability that the younger non-breeding bucks, because they are not stressed by breeding activity, will produce larger racks. The increased number of older bucks may also shorten the length of the rut and make it occur earlier. This could mean that hunters who prefer to hunt during the rut might be forced to hunt a month earlier, and they might be forced to take up archery hunting, or game managers might be forced to change the timing of some hunts. But, the end result of an increased number of older bucks will create a healthier more balanced deer herd, and increase the odds of hunters seeing more, and bigger, bucks.

Responsible Deer Management
Any type of deer management should take into account many factors; herd size, buck to doe ratio, age structure of the herd, fawning rates, type of habitat, available food sources, seasonal use of the habitat, and hunting success by age, and sex. One of the first steps in deer management should be to determine the size and makeup of the herd. A fairly accurate count of all the animals should be taken to determine buck:doe:fawn ratio and fawning rates; to determine if the herd is in balance with the available habitat, so that overuse of the habitat by the deer does not occur; which could resulting in habitat destruction, poor nutrition, starvation, disease, stress, and poor reproduction and growth of the deer herd.

Responsible Deer Management is designed to produce a socially balanced deer herd by keeping the herd at or below the carrying capacity of the habitat; by balancing the buck to doe ratio of the herd; by ensuring that there are adequate numbers of both sexes and all ages classes of deer in the herd, so that maximum breeding occurs at the appropriate time of the year.

In order for Responsible Deer Management to work hunters and game managers must realize that:

  1. The habitat can carry only so many deer, it makes no difference whether they are bucks or does. Once the number of deer exceeds the carrying capacity of the habitat there will eventually be habitat destruction, which can lead to disease, stress, and starvation of the deer. Or the deer, particularly younger bucks, will leave to find more suitable habitat making them susceptible to injury and death by natural causes, hunting, or vehicle collisions.
  2. Once the carrying capacity of the habitat has been determined, the total number of deer should be kept below that capacity, so that there is adequate nutrition in winter, and in case of forage and habitat loss due to natural causes.
  3. Because the habitat can carry only so many deer, and one of the goals of Responsible Deer Management is to ensure that there are appropriate numbers of both sexes, and all age classes of deer, one of the first objectives should be to balance the buck to doe ratio of the herd. The best way to increase the buck:doe ratio is to remove some of the does. In order to keep the buck:doe ratio stabilized an appropriate number of both bucks and does should be removed every year.
  4. To increase the average rack size of the herd younger bucks must be allowed to reach four to five years of age, which is when they begin to develop larger racks. It may be four to five years before there are significant numbers of larger racked bucks available.
  5. The oldest and youngest deer, and bucks that are exhausted from the rut, are usually the weakest and the first to die. In order to keep weaker deer alive when they are under stress their health needs must be provided for.
  6. Increased deer attraction to a particular property, improved survival and fawning rates, and increased body and antler size can be achieved by providing adequate cover and water, planting deer forage and browse, and providing year round minerals. Supplemental feed should be supplied in the winter and early spring when deer are stressed.

Social Structure
In ideal conditions the buck to doe ratio should be one buck to one doe (1:1), in areas where quality management has not been practiced it may be as low as one buck to three does (1:3). Keeping the buck to doe ratio in balance helps increase the number of available trophies. It can also improve the social ranking, health and reproductive rate of the herd. A herd of 100 deer with a makeup of 50 percent bucks and 50 percent does will not increase by 100 percent per year, because some of the does will be too young to breed and some too old to conceive. Even if each doe produces twins the natural mortality rate generally keeps the yearly increase below 100 animals per year. If you are trying to increase the number of trophies in the area you must remember that the habitat can only carry so many deer, it makes no difference if they are bucks or does. In order to keep both the habitat and the animals healthy the herd must also be kept in balance with the carrying capacity of the habitat.

Carrying Capacity
Let's assume that there are 100 animals with a 50:50 male to female ratio and the property has a carrying capacity of 150 animals. If every female produces twins and 3/4 of the young survive the herd is now above carrying capacity of the land with 175 animals. Up to 25 animals should be removed through natural mortality, predation or hunting to prevent habitat destruction and starvation. If half the young are male and half female, and no natural mortality or predation occurs the male to female ratio must be kept in balance by removing 12 males and 12 females the next year. This will keep the herd at carrying capacity. But, the herd should be kept below carrying capacity. By keeping the herd below capacity you insure that if a severe winter, drought or habitat destruction occurs the animals may still survive.

In many cases hunters only remove the males from the herd, which can be disastrous. If 25 males are removed from the herd there will be 37 males and 62 females, leaving 99 animals. Some of the males shot will be 1 1/2 to 3 1/2 years old and will never have a chance to become trophies. But, the real problem is that there are now 62 females that can conceivably produce 124 young with a 75 percent survival rate, increasing the herd by 93 the next year for a total of 192, with 83 males and 109 females. Because the herd is above carrying capacity habitat destruction is likely to occur. If the hunters again remove only males, taking 42, there are still 109 females instead of the original 50. If the practice of taking only males continues there will not be enough mature males left to ensure that all the females will be bred during the peak of the rut; some late born fawns will starve or die of exposure, and the population may crash. Even if the population doesn't suffer the number of trophy males will decline.

In order to produce trophy males some of the females must be taken each year. If the habitat is at carrying capacity and the herd balanced (as many hunters wish), as many females as males must be taken in order to keep the herd in balance with the habitat. If the herd is kept below carrying capacity there may be enough forage even if the harvest quotas are not met; production is higher than normal; or forage production is reduced by unforeseen circumstances. The best strategy is to keep the herd below carrying capacity, and the male to female ratio as balanced as possible, to produce the highest number of trophy class animals.

Ground Cover Foods
To improve the forage quality in your open areas you can plant perennial ground covers of forbes. Most deer books tell you that deer eat forbes. But what are forbes? They're wildflowers. Good perennial forbes for deer include Birdsfoot Trefoil, Cicer milkvetch, Crownvetch, Lancer Perennial Pea, Lathco Flat Pea, Lespedeza (Bi-color, Kobe, Korean, Serecia) and Sainfoin. If you want to have more people interested in CRP and habitat restoration, plant annual wild flowers in your CRP fields; landowners, farmers, nature lovers and non-hunters will love it.

Food Plots
Once spring arrives the animals seek out new green growth which you can supply through a food plot.. The traditional food plantings for deer are alfalfa, corn, fescue, soybeans, rye grass, oats, and clover (Alsike, Arrowleaf, Crimson, Huia New Zealand White, Ladino [Regal, California]). You can also plant Dwarf Essex Rape, Kale and Small Burnett. Many of the available wildlife food mixtures contain three or more plant types that mature at different times of the year to provide nutrition from spring to winter. Choose a brand that is designed for your area. Even if there is already adequate forage in the area the deer soon discover food plots and begin using them in the spring and continue using them through the hunting season. This makes it much easier to pattern the deer in the fall.

Specialty Foods
I am a firm believer in planting pumpkins and squash to attract deer. Deer love these large, carbohydrate rich vegetables so much they will dig down through frozen soil and snow to get to them. During the growing season you will have to enclose the area with a fence high enough that deer can't jump, or use an electric fence to keep them out. Once the vegetables are ripe and deer season opens, take down the fence or turn off the electricity and watch the deer flock in. Every deer within two miles used my 2 acre pumpkin patch well into January.

If you want to purchase any of the above mentioned plant species contact your local seed dealer, or Kester's Wild Game Food Nurseries, Incorporated: PO Box 516, Omro WI 54963, FAX 1-920-685-6727. For browse and mast trees contact your local nursery, or Musser Forests, Inc. PO Box 340, Indiana, PA, 1-412-465-5685

Soil Preparation
Before you plant you need to test the soil to see if you have to improve it, and then prepare the soil, which you can do in a number of different ways; burning, plowing or discing, spraying, mowing. Consult with your conservation agent about testing and improving the soil , and the best way to prepare the soil within your budget. Burning is usually the least expensive way to prepare soil for planting, but it can be dangerous. Fire can be used to set back succession on a variety of plants and habitats for better habitat. Most prairies and meadows can benefit by controlled burns, which often cause long dormant natural annual seeds to germinate. Be sure you find out the local regulations before you burn.

If you want to break up stands of sod forming grasses that are choking other forms of vegetation you can plow or disc the soil. Then you can let the area grow back naturally, or you can plant more desirable vegetation or food plots. If you want to completely start over with a new CRP plot or food planting, you will probably have to kill the existing vegetation with Roundup or Plateau. Small to medium stands of grasses and forbes make great deer habitat. You can improve a stand of grass by mowing it in strips to manipulate the existing vegetation, to provide easier movement for the wildlife, to increase habitat diversity, and to enhance the food and cover value of the habitat.

There is one factor that contributes greatly to the growth of big racks that you can't control, water. Available ground water, whether through rain, snow pack or irrigation is required for plant growth and the assimilation of vital nutrients for the plants. Too little rain means poor forage conditions for the animals, and poor growth conditions for racks. There isn't much you can do about inadequate moisture in your area. You can provide more watering sources on your property by damning creeks and gullies to collect runoff water, and by digging wildlife ponds and wells. Make sure that existing or new water sources have sufficient and easy access for the game. Clean them out regularly to provide good water.

Improving the existing habitat and providing food plots, supplemental feed, minerals and water will not only increase the health of the animals, it will attract more animals to the area. Once you have a population that is at or below carrying capacity, you can begin to selectively hunt to balance the male to female ratio, and take only the trophy class animals and a few does a year. When you begin to see lots of small racked animals "Let 'em go and let 'em grow." Then begin harvesting the bigger, older bucks.