Terrain and topographical elements play a major role in where deer feed, travel and bed. The author says that understanding this relationship can help you better manage your deer herd and habitat. (Photo by Jason Loftus, Untamed Images)
March 18, 2025
By Dr. James C. Kroll
In the early 1970s, I founded the Institute for White-tailed Deer Management & Research at Stephen F. Austin State University in Texas. I wanted the Institute to conduct meaningful research, so the first thing we did was to organize “focus groups” made up of landowners, hunters, foresters and wildlife biologists. We asked them to answer one simple question: What do we need to learn about whitetails?
The groups reached a consensus on two topics to learn more about. First, can you plant crops for whitetails? Also, what is the behavior of mature bucks? The former led to the longest running research project ever on food plots and plant varieties for whitetails; the latter launched a 27-year study on movements, home range size and habitat preferences of bucks and does.
Our studies involved capturing and radio-collaring dozens of individuals of both sexes and age classes to monitor home range and how movements were affected by a variety of landscape and environmental variables. Deer capture had not been perfected in those days, so it was a “learn-as-you-go” proposition!
We were studying ways to shoot a deer with a syringe filled with a tranquilizer. The leaders at the time were the folks at the University of Georgia. Our first gun was a CO2 powered rifle, shooting a metal dart with a barbed needle.
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Darting a buck was not much different from bowhunting. We used one of the old Baker Tree Climbers, and you risked your life every time you climbed a tree! Shooting range is exactly like shooting an arrow, so we were very limited. After 1,200 hours of sitting and misses, we finally captured our first buck: a 4 1/2-year-old 8-pointer.
We slowly increased our success rate, but I must emphasize the word “slowly.” We tracked the collared bucks using a yagi antenna mounted in the back of a pickup, with a hand-held antenna made from a welding rod to move in on a buck to confirm his location. I remember the following deer season a fellow decided to hunt the very drainage frequented by our buck on opening morning. We sat back and monitored the buck’s movements, fearing the worst for our very valuable animal.
We knew where the hunter had decided to erect a ladder stand, and to our horror the buck was heading straight toward his location. I remember telling my graduate student, “Well, there goes all that hard work!”
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When the buck got to about 50 yards from the hunter, he suddenly stopped and remained still for over an hour! Then, he started moving south away from the hunter and circled him. The buck then got back on his trail and crossed the road we were sitting on 100 yards to our right. The hunter had picked the wrong spot, and the buck had the wind on him. He was safe, and we tracked him for two more years.
As time went on, our capture techniques improved, eventually using a helicopter and drive net. My colleague and friend, Dr. Harry Jacobson, was using a drive net in Mississippi to capture bucks for a similar study. A drive net was eight feet tall and hundreds of feet long; it was constructed like the nets marine fishermen used at that time. We used a small army of students to position the nets along terrain features. The net was then erected by two poles, similar to putting up a tipi. When a deer hit the net it would collapse over him, and our students swarmed the buck to hogtie it!
Much of what we subsequently learned appeared regularly in North American Whitetail magazine. One of the first things we learned was bucks and does might as well be different “species,” since they clearly have differences in habitat preferences during critical times of the year; a phenomenon known in ecology as “niche partitionment.” Remember, the term “niche” refers to specialization of habitat use and/or feeding habits that reduces competition. Usually, niche partitionment refers to habitat and foraging differences between species, but it also can relate to differences between sexes.
We found that does and bucks are sexually segregated most of the year, with does organized as “clans,” made up of highly related individuals. And bucks loosely organized into smaller groups dominated by older bucks. We learned doe clans remain tightly associated with drainages, branching out into the uplands to forage during good times, then retreating back toward a drainage as forage quality deteriorated. Does rarely abandon their home drainage, but bucks move freely between drainages through topographic features called saddles.
A saddle is a depression that connects the upper end of one drainage system with another along a divide. The lowest elevation in the saddle is called a col. Since doe clans are highly related, it is the job of bucks to maintain genetic diversity by traveling from drainage to drainage and clan to clan using saddles.
We also found movements by deer of both sexes are influenced by other topographic and terrain features, such as slope and aspect. Although topography and terrain may seem to be the same thing, they are not. Topography is what the surface of the land looks like, while terrain represents the features that lie on this surface. Slope is reported as a percentage, calculated by dividing rise by run, times 100. A hillside is considered steep if the slope is 15 percent or greater. Deer are what we call, “Physiologically Conservative,” meaning they make a conscience effort to expend as little energy as possible during normal travels across the landscape. They prefer to walk along a level topographic line rather than climb a steep hill. It saves energy to do so, especially if the topographic line leads to a saddle connecting two drainages.
Aspect is the compass direction faced by a slope, which can create significant temperature and light conditions. Aspect not only affects temperatures (south is warmer than north), but even the species and growth rates of plants used by deer as forage or bedding. In addition, aspect and slope affect management decisions regarding food plots, tree planting and harvesting and road access.
If there is one hard and fast rule I’ve learned during all these studies, plus five decades of managing for whitetails on properties from Mexico to Canada, it is that white-tailed deer management is site specific; there is no such thing as “cookbook” management! Each property, no matter how large or small, contains unique combinations of land features and environments. Yet, what we did learn is that deer behavior is predictable and stereotypic, which can be used to evaluate, plan and manage properties for whitetails. You can use these same rules of behavior to your advantage in developing a hunting plan for next season, provided you gather the right information about your hunting territory. So, let’s take a look at an example to illustrate my point.
Boots on the Ground There are two types of aerial images we use in managing properties for wildlife — leaf-on and leaf-off. This image was taken when the trees were fully covered by leaves. (Photo courtesy of Dr. James C. Kroll) In 2023, we leased 260 acres of land in Kentucky for our management and hunting property for North American Whitetail TV
Our first step was to acquire current and historic aerial images and topographic data of the property. This season, we will show you how we went about creating a habitat and herd management program tailored to the property. As a preview, let’s look at our analysis to illustrate our evaluation.
We will start with a 2022 aerial image acquired through Google Earth. There is some information to gain from examining this image, but only generalized features such as openings, structures and forest/brush areas. There are two types of aerial images we use in managing properties for wildlife — leaf-on and leaf-off. As the names imply, these images were taken when the trees were fully covered by leaves and as the leaves were beginning to turn color and fall. Now, we can learn a lot more about the property!
This image was taken as the leaves were beginning to turn color and fall. The yellow circles indicate stands of older oaks, which are important to both hunters and deer. (Photos courtesy of Dr. James C. Kroll) We can learn a lot from the leaf-off imagery. It turns out a good portion of the property contains younger stands of trees, and the older oaks (colored leaves) are limited to some areas (circled in yellow). The dark green areas turned out to be cedars, which can serve as thermal cover.
Is there even more to learn using our knowledge about the importance of topography and terrain in directing deer movements? Using the OnX Hunt App, we added a layer of information about the topography of our Kentucky lease. Looking at the topographic layer, we see that the land contains several steep drainages off three creeks. We identified three travel corridors using the drainages on the property (yellow lines), one winter thermal bedding area (white oval) on a topographic feature called a bench, and a major saddle (green).
From all this, we predicted the saddle area would be a prime location for a hunting stand, and on-the-ground reconnaissance yielded a host of sign post rubs, indicating a staging area. So, using the information we gained from now almost 50 years of research on deer movements, in one day we homed in on the prime hunting location for this property! The proof is the staging area and numerous rubs leading from one drainage to another via a saddle.
The next step in this analysis is to get a good mapping app, like onX Hunt , that will allow you to map out the rubs and signposts on your property. Then place them as a mapping layer over the images I discussed above. I know this sounds pretty high-tech, but the average hunter should be able to develop the analysis and have fun doing it! You also will greatly increase your success as a hunter. Now, let’s look at management.
Topography and Terrain Analysis for Management The author and his colleagues identified three travel corridors using the drainages on the property (yellow lines), one winter thermal bedding area (white oval) on a topographic feature called a bench, and a major saddle (green). All these elements will have a place in the team’s hunting and management plans. (NAW STAFF photo) The greatest limitation to the installation of food plots and other deer habitat management practices are topography, terrain and soils. A complete analysis of the topographic relief will help identify the locations and challenges to activities, such as clearing for plantings and developing better access on your property.
The topographic maps reveal the limitations your property has regarding physical development, but the soil maps (we’ll discuss in another column) will guide you to the final determination of where to plant and what to plant in your plots. It also will show you where you need to implement native forage developments, such as timbering and prescribed burning. Remember, you should locate forage developments as near to established travel corridors as possible. You want to make it convenient for your deer to travel and have access to both planted and native forages. Lastly, an analysis of the availability of both winter and summer thermal cover will help you find places where these critical habitat features should be developed.
I hope this column has made you more aware of the role topography and terrain has in both deer management and hunting. When I began my career and research in the early 1970s, very few of these tools, and certainly little of this information, were even available. Take advantage of them, and you will be very pleased with the results!
