Deer Management Through Browse Use

Browse consumption can be used for better whitetail deer management

Browse consumption can be used for better whitetail deer management

Habitat is the cornerstone of white-tailed deer management. Plant communities, an important component of habitat, are composed of forbs, grasses, and woody plants (browse). Healthy, diverse habitat sustains native wildlife populations and almost always represent healthy deer herds. However, browsing of woody plants by white-tailed deer and domestic livestock may have negative impacts on perinneal shrubs, trees and the overall habitat.

Excessive browsing may lead to decreased plant vigor, increased susceptibility to disease, or decreased reproduction and seeding establishment. Stresses such as these could potentially cause the disappearance of some plant species important for quality deer habitat. Consequently, deer biologist typically quantify the most palatable browse plants in an area in an attempt to monitor browsing pressure by the local deer herd. Sound deer management decisions can be made by recording browse plant use by white-tailed deer. Continue reading “Deer Management Through Browse Use”

How Many Deer are Too Many?

Let’s face it, most landowners want to see plentiful groups of white-tailed deer running around on their property. However, those interested in improving their herd through deer management practices should want to see healthy individual animals. Why is this, you ask? That is because healthy animals are an indicator of good deer habitat and animals in good condition make for healthy white-tailed deer herds. If individuals within a population are in poor condition, then the overall population itself is in poor shape. So although we may want to sustain as many deer as possible on a ranch, what is the ideal number or the target number? The quick answer is that carrying capacity is based on habitat and environmental conditions.

In short, it’s all related to soils and precipitation, which in turn determines the plant species that grow in a particular area. But even with that said, we all know that the quality of deer habitat can vary based on a variety of factors, even within a single county or even just a mile or two down the road. The previous few sentences probably did not help anyone develop a population goal for their property, but hopefully it did help in understanding that the carrying capacity for a particular piece of property can vary widely between regions, counties, and individual ranches. To help you get a handle on how many deer you should or could have, I have outlined three measurable factors that landowners and hunters can use to monitor the health of a deer herd.

Deer Management: How Many Deer are Too Many?

Deer Body Weights

From experience, I can always determine if a property has too many deer for the available habitat based strictly on deer body weights. Deer are kind of like people in the fact that if food is available, they will usually eat it. Removing protein pellets, food plots, or any other type of forage supplement, there is only a limited amount of forage that deer can use on a particular ranch. If the ideal population size for a ranch is 100 white-tailed deer, then the property will support a population of 100 (or fewer) healthy deer. However, if more than this number of deer are on the ranch, say 130, then all of the deer on the property will be less healthy.

This phenomenon is most easily measured and assessed by collecting the field-dressed body weights of hunter-harvested deer off the property. The health of individual animals can be determined by comparing its body weight to that of healthy deer in the same age class. For example, mature (5 1/2+) and healthy white-tailed bucks anywhere in Texas should field-dress at least 125 pounds. Mature does should weigh around 80 pounds. Both sexes can easily weigh more than these quoted minimums, but they should at least reach these targets. Minimum field-dressed weights for healthy deer will vary depending on where in the country you are located, so contact your local wildlife department to get optimal field-dressed body weights (by age class) for your area.

Reproduction Measured Through Fawn Production

Fawn production is a good measure of habitat and herd health because nature does not lie. Healthy animal populations, regardless of species, will have high reproduction, high survival, and good recruitment in environments that provide everything they need. Animals need food, cover, and water, and white-tailed deer on no different. If your property provides high-quality deer habitat, then the cover and resulting food are in place.

The availability of food, as it relates to habitat condition, really impacts fawn survival. This is why fawn crops are poor during drought and high during years with high amounts of precipitation. Habitat that is being over-used by too many deer will be in poor condition, even during a “good” year. In addition to field-dressed body weights, fawn survival is generally a good measure of herd health. High fawn survival means healthy habitat. To estimate the fawn survival of the whitetail herd found on your property you will need to conduct daylight deer surveys annually. A fawn survival rate of at least 75% (75 fawns per 100 does) is indicative of a healthy deer herd and healthy habitat.

Habitat Use and Condition

Biologist often use habitat condition, as measured through browse utilization by deer, as an indicator of habitat health. This is because trained individuals know exactly which plants deer prefer to eat, those that they will eat readily, and then those that are at the bottom of the list. As mentioned above, the availability of food is important for the health of individual deer as well as the herd as a whole. Although you do not have to become an expert in plant identification to successfully manage the deer herd found on your property, it would be a good idea to become familiar with the common browse plants on your property. This will allow you to identify browse consumption by deer throughout the year and from year to year.

Once you are able to recognize a few plants from each browse category (preferred, moderately preferred, not preferred), you will understand where on the buffet line the deer on your property are eating. However, there is a trick. Highly preferred browse plants will always be consumed at high levels. The real measure of habitat health will be determined by whether or not deer are eating plants they really do not want to eat.

Developing a Target Number for the Deer Herd

Each ranch manager should determine the whitetail carrying capactiy for their ranch. This number may vary over time, but without a goal there is no need for deer management. How can one manage for something if they can not measure or detect changes? As you can tell, record keeping becomes very important if you expect to monitor the progress of the deer found on your ranch. In short, there are two ways to determine the ideal deer population size for your property. You can work from the top down or from the bottom up.

A top-down approach would be to contact a state biologist, have them come look at the habitat on your property, and then them give you a ball park number on how many animals your habitat will carry. A bottom- up approach would be for you to monitor individual deer body weights and estimate fawn production annually. In either case, you can use the same information to make the appropriate changes. If the body weights of field-dressed deer are less than optimal for the area and fawn production is low, then there are too many deer for the habitat. Adjust the population carrying capactiy downward and shoot more animals. If, however, deer are in good condition and there are plenty of fawns, then it may be possible to increase the population incrementally as long as negative changes are not measured.

Of course, the above data will be of most benefit if you are also conducting annual camera surveys or spotlight surveys. And if you are at all serious about deer management, yearly deer surveys are a must for your ranch. Deer surveys are designed to help you estimate the number of white-tailed deer on your property, but then, using body weight and fawn production data, you can determine if that is the right target for you. Once you have identified the carrying capacity for your ranch, then it’s just a matter of conducting annual surveys and harvesting the excess population. Of course, if you keep the herd at carrying capacity, then that fawn production data will give you a pretty good idea of how many animals will need to be removed each year!

Fire Creates Better White-tailed Deer Habitat

White-tailed deer, like many wildlife species, prefer habitat that is at lower successional stages. Simply stated, deer like plant communities that are dominated by plants that are considered first responders after disturbance. Any disturbance helps set back plant succession, whether it be disking established areas, clear-cutting portions of forests, or natural or prescribed fire. And although hunters understand that deer management practices are designed to improve habitat, many habitat management practices are really only designed to mimic processes that occur naturally.

Of course, when it happens naturally land managers have very little control. Such was the case last year in Texas when the almost 15,000 acre Chaparral Wildlife Management Area (WMA) unexpectedly caught fire. It was March of 2008, but because of extremely dry spring conditions, a fire that started adjacent the area burned 95% of the state-owned WMA! Anyone that knows anything about the Chaparral WMA knows that the area is representative of South Texas brushland, but active habitat and deer management practices maintain a healthy deer herd that boast some big ole whitetail bucks.

Prescribed fire is an effective management tool for deer throughout the white-tailed deer’s range because most native brush species respond well by root-sprouting, regrowing, and providing high-protein browse. You see, most plant species are well-adapted to fire, but all deer managers that use fire as a management tool prefer prescribed or controlled burning. The fire that swept across the Chaparral WMA, on the other hand, was a wildfire. And although wildfires and prescribed fires ultimately have the same impact on native plants, prescribed fires are planned and allow burners the most preparation. Prescribed fires allow landowners the ability to pre-select the areas to be burned and the conditions under which they are burned.

Chaparral WMA Fire of 2008

For those interested in using fire as a management tool, it’s recommended that no more than 20% of a property be burned annually. This keeps different successional stages of plants located throughout the property and provides deer with optimal forage. I mentioned earlier that the wildfire that crossed the Chaparral burned 95% of the research WMA. Keep in mind that the perimeter of the area is game-fenced and very few deer were found dead post-fire, so that left all the deer found on the 15,000 acre property about 700 non-burned acres to forage. But white-tailed deer are resilient animals.

Chaparral WMA staff and researchers from Texas A&M University-Kingsville used the effects of the wildfire to monitor how deer living on the area would respond. What would deer eat in the short-term? Would there be enough food to maintain body condition and support fawning? That was just a few of the questions managers needed to answer to determine if the deer herd could respond the the widespread setback in habitat.

It’s important to note that the month of March is smack-dab in the middle of a white-tailed does’ pregnancy. And pregnancy requires a high amount of dietary input. Researchers collected does at two week intervals from mid-April to mid-June and recorded live weight, body condition, rumen contents, and the number and size of fetuses. A total of 28 does were collected and 23 pregnant does carried 6 single fawns, 16 twins, and 1 set of triplets. Shortly after the fire, rumen contents consisted primarily (90%) of cactus and grasses. However, deer shifted to forbs and mast (fruits) as these foods became available after the fire.

 Chaparral WMA Post-Fire

Data collected on the Chaparral WMA found that deer were able to maintain body condition and pregnancy after a large-scale fire. However, the management area did have a lot of things going for it that may or may not be available in some areas. First, the deer herd was below the carrying capacity of the land prior to the fire. In addition, the area was fortunate to have an abundance of cactus that provided a moisture-rich post-fire food for white-tailed deer. Although deer were able to switch their diets in order to survive, would this be the case in your area after a wildfire?

Fire is one of the most beneficial tools in wildlife management because when used properly it is very economical. In addition, fire releases nutrients that are bound in dead organic material, fire stimulates the germination of certain plant species, and fire controls plants such as blueberry cedar that are not fire adapted.  And although we have learned that whitetail can cope with large-scale fire in South Texas, I do not recommend burning more than 20% of your property on an annual basis. Just keep in mind that with burning 90% of the work takes place before you strike the first match.

Bottomlands are Important White-tailed Deer Habitat

Bottomlands are Important White-tailed Deer Habitat

Creeks, streams, rivers, and all riparian areas are important habitat for white-tailed deer. Not only do these areas typically provide access to water and good bedding cover, but they also serve as great travel corridors and have the most fertile soils in most any area. Great bottomland or riparian soil is typically clay and silt-rich and full of nutrients and natural fertilizers.

So why do riparian soils (those found along drainages) serve as outstanding areas of food production areas for whitetail? Well, we know the soil is nutrient rich and this happens over time from flooding and drying and the decay of organic matter. But in addition to being rich in organic matter, riparian soils have a high water-holding capacity. In fact, any soil rich in clay and silt has this ability, but let’s not forget that bottomland soils are also adjacent a seasonal or permanent waterway.

Even without rainfall, many of the plants adjacent a creek or river can simply extract water from the soil below like any other plant, but there is a lot more water. Thus, the amount of forage produced in bottomland areas is often 3 to 5 times that on upland soils during the same year. This soil provides for an abundance of a very lush and diverse plant community. And remember, deer like diversity especially when it comes in the form of forbs and browse!

So what should you do with bottomland areas on your property? As important as they are for deer habitat and the health of the overall wildlife community, I recommend protecting them and revegetating them if necessary. Many bottomland floodplains are cleared and become prime farming and grazing land. If you are serious about deer management, encourage native vegetation to retake these areas, saving some portions for great food plot areas.

Bottomlands are Important White-tailed Deer Habitat
This ag field has a filter strip – but to benefit deer, it needs to be “let go” into native weeds, grass, and brushy plant species

In addition, permanently vegetated areas along creeks, streams, and wetlands reduce erosion and sedimentation, stabilize streambanks, improve plant diversity, and improve wildlife value of these sensitive areas. I also recommend establishing vegetative buffers or filter strips along water courses or runoff areas to trap valuable bottomland soil in the event of heavy rainfall and or channel flooding.

So here’s the bottom line: White-tailed deer and other wildlife love bottomland areas. Not only do these areas attract big bucks, but because of the quality and diversity of habitat, it attracts lots of does. And to a big mature buck, that’s a good thing!

Deer Habitat Management – The Fundementals

Deer Habitat Management - The Fundementals

The mangement of white-tailed deer and their habitat has become of increasing concern in recent years. Hunters and landowners realize that it takes more than luck to produce outstanding deer on their land, and improved habitat conditions are a major factor in regards to deer development.

Fundamental requirements that must be considered when managing for white-tailed deer habitat include food, cover, water, and the proper distribution of these elements. Habitat management must be directed at maintaining a productive and healthy ecosystem. The ecosystem consists of the plant and animal communities found in an area along with soil, air, water and sunlight. All management activities should be aimed at conserving and improving the quantity and quality of soils, water and vegetation. There is no substitute for good habitat. Good deer habitat makes good wildlife habitat, and it keeps your ranch looking great. First and foremost, managing for plant diversity is essential. A diverse habitat site will have a good mixture of various species of grasses, forbs and browse plants. Many of these plants will be at various stages of growth, which adds another element of diversity.

The diversity of vegetation increases the availability of food and cover for wildlife species. A greater diversity of range plants results in more food being made available during different periods of the year. The volume and diversity of plants protects the soil from erosion. Also, the decomposition of vegetation helps restore needed minerals to the soil to sustain plant life. An abundance of vegetation improves the water cycle by trapping water from rains, thereby preventing excessive runoff which leads to the erosion of soils and flooding of streams.

An ecologically-based habitat management program will serve to improve the plant community of your rangeland by increasing vegetation quantity, quality and diversity. This improvement in the plant community will not only conserve and enhance the soil, but improve the water cycle as well. A greater diversity of all forms of life, including microorganisms, insects, reptiles, amphibians, birds and mammals is achieved under a sound management scheme. The long term health of the land is improved and conserved for future generations to utilize as a source of income, recreation and for aesthetic enjoyment.

In Texas, the climax herbaceous vegetation community of most rangelands is dominated by grasses with a low percentage of forbs. While this may be suitable for livestock and for a few species of “grassland” wildlife, many wildlife species are more dependent on the seeds and foliage of forbs (commonly called “weeds”) than on grasses.

Keep this in mind: plant communities with a diverse array of “weedy” plant species are more productive than a community dominated by perennial grasses. Periodic disturbances such as fire, soil disturbance, livestock grazing, and mowing can set back plant succession and maintain a diverse plant community. Remember, it’s important to mix it up to keep deer habitat healthy and productive.