Rainfall, Habitat and Antler Growth

Managing for good white-tailed deer habitat on a property is the key to maintaining a healthy deer herd. Plain and simple, deer in good body condition are more productive than deer in poor condition. A problem many landowners face is that Mother Nature does not always do her part. This is the major reason why supplemental feeding has become an integrated part of deer management on many ranches.

A property can generally have good deer habitat, but that does not necessarily mean that the plants found on the property are in good condition. Rainfall makes a big difference from year to year. In fact, research conducted in South Texas, on what was coined the “South Texas Buck Project,” by the Caesar Kleberg Wildlife Research Institute at Texas A&M-Kingsville found that spring rains explained 70% of the year to year variability in buck antler size.

Grow Bigger Bucks: Deer Management, Habitat Improvement and Rain!

Spring rain and antler growth were highly correlated, meaning bucks grew larger antlers following wet springs and smaller antlers following dry ones. During the South Texas Buck Project, researchers classified spring rains as those occurring during March, April and May. And over much of the whitetail’s range, it is during this time of the year when good rainfall can produce bountiful crops of high protein forbs and set up browse plants for the long, hot, and typically dry summer. If the rains do not arrive, then deer can forget about the would-be protein buffet.

Okay, so I will admit that South Texas is much different than many parts of the white-tailed deer’s range, including most parts of Texas, but the results of this study are a bit staggering. The data collected during the South Texas Buck Project conclusively found that spring rains alone accounted for as much as a 20 inch shift in gross Boone and Crockett scores for mature bucks! These findings really illustrate the importance of precipitation, habitat condition and food availability to any landowner or hunter interested in deer management.

Texas Oak: Habitat Management for Improved Whitetail Deer Hunting

So this all makes enough sense, but how can it help hunters on their property given that they can not control the rain? Well, no one can turn on the faucet that makes it rain, but hunters can control whitetail food availability through management practices such as maintaining proper livestock grazing rates, brush management, prescribed burning, supplemental feeding and managed deer harvest. Allowing deer to grow older is one way to produce more mature bucks, but age is not the only factor that affects antler size.

In mature bucks, rainfall determines whether that 20 inch shift I mentioned previously ends up being 20 inches up or 20 inches down. Food availability is of utmost importance in allowing old bucks to reach their genetic potential. For hunters interested in trophy buck management, I would seriously considering shooting any buck 5 1/2 years of age following a wet spring. Why? For the simple reason that the chances of getting two good years in a row are slim, and therefore antlers are not likely to be better the next year. During a dry spring, such as this one, hunters may want see if those deer can add that 20 inches back on next year.

Improve Wooded Habitat for Whitetail

Hunters and landowners  interested in deer management know that the bread and butter of white-tailed deer’s diet are browse plants. Although a deer would prefer to eat higher-in-protein forbs, those plants are primarily only available during the spring and fall. Though ideal deer foods consists of preferred browse plants and high protein forbs, many of these plants are not as abundant as they could be across the landscape.

Good deer  habitat always has some wooded component. This woody structure provides screening shelter, overhead protection, and food from both leaves and mast. This wooded component can range from brushland to  mid-story tree species to mixed forests of a variety of species. Deer habitat can vary a great deal from place to place, but too much wooded area can become a detriment to deer and the plants they eat. Proper habitat management practices, however, can make the most out of the land you hunt. Continue reading “Improve Wooded Habitat for Whitetail”

Better Fawn Survival for More Bucks

It often amazes me when I hear an uninformed hunter talk about deer management and the habitat requirements of white-tailed deer. After hearing them speak just a few sentences, it’s obvious that they do not have a clear understanding of a whitetail’s habitat needs or the foods that they eat. This blows my mind! After all, these are the same guys that proclaim to “love” hunting. But I suppose there is a big difference between deer hunting and white-tailed deer management.

Deer hunting can exist without deer management. After all, you don’t necessarily need many (or any?) deer to go deer hunting. However, white-tailed deer management can not occur without hunting as part of the overall equation. In short, you can love hunting while being indifferent to management, but if a deer management program is in place then hunting is part of the package.

So where am I going with this? I guess what I’m trying to do is illustrate is the difference between hunters that simply shoot deer and those that manage for them. There is nothing wrong with either of them. Besides, we all go through various stages in our hunting lives. However, there comes a point when most hunters connect the dots and realize that there is a strong relationship between the habitat that the land provides and the health of a local deer herd. Continue reading “Better Fawn Survival for More Bucks”

Doe Harvest with Caution?

Not all that many years ago it was considered unsportsman-like to shoot a doe deer. Since then, however, wildlife biologists and hunters have realized that proper doe harvest is an important part of white-tailed deer management, although I suspect there is a small percentage of landowners that still do not allow doe to be harvested on their properties. After all, a landowner has the ability to be more conservative than the law and choose not to harvest antlerless deer, even if hunting regulations permit it.

But is a no doe harvest really justified? Maybe, but then maybe not—particarly if the only reason holding someone back is the “old school” philosophy of not shooting female deer. It is true that the shooting of does may not be justified in some areas. Not every deer whitetail population can sustain regular doe harvest. Some deer herds may allow periodic doe harvest, such as every other year or every third year, for example, while others need regular (annual) doe harvest to thrive. So why does the harvest of whitetail doe vary by area? Continue reading “Doe Harvest with Caution?”

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!