How do I know if there are too many deer for my land to support? How can I determine whether or not the heavy doe harvest over the last few years is helping the habitat? Is the deer herd healthy? When leasing or buying land, what can tell me whether or not the place is suitable for producing quality deer?
The questions above and many more can be answered by conducting a browse survey. Browse, the leaves and twigs of woody plants, form the mainstay of a deer’s diet. Although forbs (i.e. broad-leaved weeds) and mast (e.g. acorns, mesquite beans and fruits) are highly preferred and nutritious, both are seasonal by nature. Rainfall is normally heaviest in the spring and fall. Forb growth is heavy at this time, however, once soil moisture levels become depleted, the small weeds will die out. Acorn crops usually occur in the fall, but are not dependable on a yearly basis. In contrast, woody plants are the most stable part of the habitat and can supply deer with nutrition when other food sources are not available. Browse surveys are best conducted during these stress periods, often in late summer and/or late winter.
It is vital to point out that not all browse plants are created equally. Deer are very selective when browsing woody plants. In Central Texas, Kidneywood is considered a first-choice plant. On the other hand, Agarito is rarely browsed when other woody plants are available. To simplify matters, browse plants are categorized using first, second and third-choice classes. First-choice browse are comprised of plants that deer prefer over any other. These plants are sought after because they are the most palatable and nutritious. Second-choice browse are not as nutritious as first-choice species, but they make up for it in abundance on most ranges. Lastly, third choice plants are consumed only when first and second-choice plants are not available. It is important to note that some of the moderately preferred species can be utilized to a greater or lesser degree depending on season of growth, growth form, soil type, etc. However, these categories are an accurate simplification of browse preference as they pertain to white-tailed deer.
The first and most time consuming step in conducting a browse survey is identifying the plants on your property. Field guides such as A Field Guide to Common South Texas Shrubs (Taylor et al. 1999) and Trees of Central Texas (Vines 1984) and Trees, Shrubs, and Vines of the Texas Hill Country (Wrede2005) are very helpful. Other helpful resources are county extension agents and NRCS personnel. Diagnostic keys, such as Illustrated Flora of North Central Texas (Diggs et al. 1999) can be of great value to the more taxonomy-minded person. A proper plant inventory and identification are critical and will increase your overall knowledge and appreciation of the ecosystem in which you are charged with managing.
There are many different browse survey techniques available. Some are best suited for particular situations and to attain exacting information while others involve more of a “wide” approach. For the purposes of this article, however, we will deal specifically with the cursory survey. As stated many times here before and as one of the Golden Rules of wildlife management claims, “Quality habitat produces quality animals.”
The cursory survey involves the “wide” approach whereas the observer is looking at the big picture as it pertains to habitat. One of the first steps in performing a cursory survey is to know the boundary, shape, and topography of the land. This can easily be gathered from an aerial photo, topo map, soil survey map, or have someone knowledgeable about the property draw you a relatively detailed map. Once in hand, consider the focal points of the property, i.e. rivers or major creek drainages, mountains/hills, food plots, supplemental feeding stations, permanent water sources, etc. Next, note the areas that are farthest away from such focal points. Look for large blocks of brush, slight slopes, meandering roads, and far reaches of the boundary fences. With map in hand, begin to drive the roads. As the survey begins, take special note to observe the soil type and the plant community growing on each different soil AND THE CONDITION of the plants growing there. There are specific plants that grow on specific soils for specific reasons. Take note of any mechanical manipulation of the habitat. Did you see the old regrowth from the 1940’s rootplow? Did you notice the brush community that now resides there? What condition is it in? Could you tell that the previous owner overstocked this property some years ago? The brush and the condition thereof, tell a story. Reading the story is not difficult, but it does take some study.
Stop the vehicle often and get out. You want to select stops AWAY from the previously mentioned focal points so that the survey is not biased. These focal points serve and attract wildlife. Thus, the increase usage of those particular areas may show signs that are not particularly representative of the property. Avoiding the focal points and concentrating on the areas between them will give the observer the “true story” of the condition of the habitat.
Noting the different soil types, brush communities, and condition of each, get out of the truck and take a short walk. Stepping away from the road and into the nearby brush, the observer will witness the true integrity of the brush there. Now, search out the individually identified plants as they pertain to deer’s preference rating for your area (see below). Does the plant look healthy? Can you identify the current year’s growth? If not, does the plant appear “hedged” or pruned in any way that is within the normal range of a feeding deer? What about the herbaceous ground cover? Any grass or forbs around? If so, what condition are they in? If not, ask yourself why not or what happened to them? After making notes, get back in the truck and continue down the road. Continue doing this for as long as it takes to uniformly cover the property. Small acreage may only require a couple of hours whereas large acreage may take a full day or more.
Now that you have thoroughly surveyed the property, walked through the brush, and learned about the history of the place, what do you think? Were you impressed with what you found? Did the amount of ground cover, lack of hedging, plant abundance and diversity catch your attention, or did you notice something else? What about the animals you saw during your survey? Did you see healthy animals or were they up feeding all day and still appeared thin and needy?
With notes and observations fresh at hand, now is the time to make some hard decisions. If your survey results did not impress you, then act now. Habitat is where the animals live. They live there 365 days a year and 24 hours a day. If the habitat is in need of improvement, then so are the animals. By reducing the number of animals utilizing the habitat, you will create time and energy for it to recover. As the habitat improves, so will the animals that use it. Do you need to add additional cross-fences to compliment your grazing system? How many mouths can this range support?
Take this knowledge to the field. Do it right now as hunting season begins and while winter sets in. Surveying your habitat under stressed conditions is the optimum time to do so. It will tell you the truth. You may or may not like it, but it will not lie. If you need to reduce numbers then now is the time to enact such measures. As stewards of the land and “keepers of the gate”, take this experience into the field today and put it to work for you. You and all the animals on your property stand to benefit.
Below are some of the more common plants placed in their overall respective browse categories for South and Central Texas. Of course, with differing environmental conditions, soil types, and mechanical manipulation, some of these plants may be moved into slightly different categories.
South Texas Plains Edwards Plateau Region
First Choice First Choice
Cedar elm Chinaberry
oaks, Spanish and Texas
Granjeno Littleleaf leadtree
Guayacan Texas mulberry
Southwest bernardi elms, Slippery and Cedar
Texas kidneywood Trumpet vine
Second Choice Second Choice
Blackbrush Skunkbush sumac
Guajillo Flameleaf sumac
Huisache Fourwing saltbush
Live oak oaks, Post, Live, Blackjack
Lime prickly-ash old man’s beard
Lotebush Common greenbriar
Wolfberry Netleaf hackberry
Third Choice Third Choice
Agarito Agarito Elbowbush
Cenizo Western soapberry
Knifeleaf condalia Ashe juniper
Lantana Texas persimmon
Texas persimmon Mexican buckeye
Mountain Laurel Mesquite