Comparative Food Habits of Deer and Three Classes of Livestock Author(s): Craig A. McMahan Reviewed work(s): Source: The Journal of Wildlife Management, Vol. 28, No. 4 (Oct., 1964), pp. 798-808 Published by: Allen Press Stable URL: http://www.jstor.org/stable/3798797 . Accessed: 13/07/2012 12:15 Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at . http://www.jstor.org/page/info/about/policies/terms.jsp . JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact [email protected]. Allen Press is collaborating with JSTOR to digitize, preserve and extend access to The Journal of Wildlife Management. http://www.jstor.org COMPARATIVEFOOD HABITSOF DEERAND THREECLASSES OF LIVESTOCK CRAIGA. McMAHAN,Texas Parksand Wildlife Department,Hunt Abstract: To observe forage competition between deer and livestock, the forage selections of a tame deer (Odocoileus virginianus), a goat, a sheep, and a cow were observed under four range conditions, using both stocked and unstocked experimental pastures, on the Kerr Wildlife Management Area in the Edwards Plateau region of Texas in 1959. The animals were trained in 2 months of preliminary testing. The technique employed consisted of recording the number of bites taken of each plant species by each animal during a 45-minute grazing period in each pasture each week for 1 year. Results indicated moderate to heavy competition for browse and mast between the deer and goat in all pastures during all seasons, and between the deer and all three classes of livestock in the winter. Browse and mast comprised over 50 percent of the deer's diet, except in the spring and summer, and over 50 percent of the goat's diet in all seasons. Following a decrease in available browse, sheep become competitive with deer for forbs. Forbs formed an average of 68 percent of the deer's diet and 65 percent of the sheep's diet in the ungrazed control pasture in the summer; the animals generally were grazing the same species. The added factors of bearing and nursing fawns, and growing antlers, contribute to the nutritional stresses on deer in the summer, the period when extensive die-offs of deer most frequently occur in the Edwards Plateau region. Competition for grass between deer and livestock probably is important only when grass is in a succulent stage in the spring and no other forage is available in quantity. Continuous grazing by animals tends to remove the most palatable species and concentrates competition on fewer, less palatable ones. Observationsfrom the numerous replications of feeding times and places allow the conclusion that this technique provides a reliable index to preferred foods and staple foods. In the Edwards Plateau region of Texas, tivity of deer and livestock in high densities most of the rangelands are grazed by two (Hahn 1945, Taylor and Hahn 1947). Pre- or more classes of livestock along with deer. vious studies of its vegetation in relation Research on the Kerr Wildlife Management to deer and livestock were reported by Area, near Hunt, Texas, indicates that deer Buechner (1944), Taylor and Beuchner when managed and harvested properly can (1943), and Whisenhunt (1949). On the provide economic returns comparable to Kerr Area, particularly the pastures in- those from domestic livestock. But a study volved in this study, the prominent vegetal of the economic feasibility of management expression is a savannah of live oak, in for livestock and deer in combination re- which Ashe juniper (Juniperus ashei) and vealed the need for more exact knowledge shin oak are conspicuous. of their competition for forage. To provide Part of the Kerr Wildlife Management such information, a study of the food habits Area contains 10, 96-acre deer-proof pas- of cattle, sheep, goats, and deer was initi- tures which are used for a long-term study ated in May, 1959, and concluded in May, of the influence of combined sheep, goat, 1960. and cattle grazing rates on deer production. The Kerr Wildlife Management Area is a Each species of animal obviously has a dif- research facility of the Texas Parks and ferent influence on the welfare of the others Wildlife Department located in Kerr and on the forage resource in general, but County in the eastern portion of the Ed- the experimental design had revealed only wards Plateau. This region, encompassing the gross influence of combinations of ani- some 26,000 square miles of central Texas, mals. probably is unique in its combined produc- Performances of deer in experimental pas- 798 FOOD HABITS OF DEER AND LIVESTOCK * McMahan 799 tures (Table 1) indicated clearly that live- Table 1. Average performances of deer maintained in ex- stock had a effect on perimental pastures with and without livestock from 1957 grazing pronounced through 1962. deer production. Only with little or no HERD competition from livestock did deer survive YEARLY LOSSES OF INCRE- and More exact PASTURES AND STARTING ADULTS MENT reproduce satisfactorily. STOCKING RATES* POPULA- (PERCENT) (PER- knowledge of the kinds and quantities of TIONt CENT) forage necessary for successful deer produc- 1 and 4 tion was needed. Heavy use by livestock 6 40 -43 2 and 5 Previous measurements of use on vegeta- Moderate use by tion (May 1959, Vallentine 1959) did not livestock 9 14 9 distinguish the effects of each kind of ani- 3 and 6 use livestock 8 14 6 mal. To obtain this information, we used Light by 7 tame animals whose activities could grazing Deer only, 8.0 acres be observed at close range with accuracy per deer 12 3 42 by what was called the animal bites method. 8 To our this method has been Deer only, 6.4 acres knowledge per deer 15 5 32 used previously only by Wallmo (1951). The author wishes to the * Each pasture contains 96 acres. acknowledge t Summation of all sex and age-classes of deer in technical assistance of T. A. Booker, for- paired pastures. merly with the Texas Parks and Wildlife Department, and the biometrical advice of This provided two groups of domestic Dr. O. C. Wallmo, the Arizona Game and livestock, A and B, with one animal of each Fish Department, and Dr. R. B. Davis, De- species in each group. In the testing sched- partment of Wildlife Management, Texas A. ule, each animal in Group A was grazed and M. University. In addition, gratitude during two different times on 1 day, and is expressed to Dr. Wallmo for his editing the following day Group B was grazed in of the manuscript. This is a contribution the same manner, during the same times of Texas Federal Aid Project W-76-R-4, and under the same conditions as Group Texas Parks and Wildlife Department, and A on the previous day. the U. S. Bureau of Sports Fisheries and In addition to training the animals, the Wildlife, cooperating. preliminary tests were intended to deter- mine: (1) the individual differences in PRELIMINARYTESTS preference for plant species within species Prior to initiating the study, the animals of livestock, (2) the influence of various to be used were trained for 2 months during degrees of supplementary feeding (moder- March and April, 1959. A mature male deer ate, light, or no feed) upon grazing behav- that had been raised as a pet was obtained ior, (3) the influence of time of day on and used because of his availability and forage preferences, (4) the length of graz- familiarity with the vegetative complex on ing period (1 hour, 45 minutes, or 30 the area. Two nanny goats, two ewes, and minutes) most suitable for providing the two cows were borrowed from the grazing desired body of data, and (5) the feasibility lessee on the area. Adult female livestock of using gentle animals in food habits re- were used because they represented the search. kind of animals most common on range- The preliminary tests were conducted on lands. a 22-acre area of uniform topography, soil 800 Journalof Wildlife Management,Vol. 28, No. 4, October 1964 type, and vegetative cover. The deer was correspond with the feeding normally given conditioned to respond to call, to following, range stock in different seasons. and to being led. The animals were trans- Several major conclusions pertinent to ported to and from the grazing area in the conduct of the study were drawn from either an open or closed (with sideboards) the preliminary tests: pickup truck, with a small livestock trailer. (1) Retaining the animals in pens and This mode of transportation did not disturb providing controlled supplementary feed the deer to any observable extent. was preferable to allowing them to graze A separate series of tests was also run in freely in a pasture between observation which the animals were allowed to run free periods. in a 90-acre trap while not being used in (2) Comparison of Groups A and B grazing observations. When a test was de- indicated that the two individuals of each sired, each animal was called to the truck, species among the sheep and goats made transported to the feeding area, and ob- forage choices that were significantly dif- served during either the early morning or ferent in statistical terms. This was not true late evening. Even though these periods of the two cows. The differences found are times of concentrated grazing by range were attributable to the greater docility of livestock and deer, the experimental ani- the animals in Group A which ate more, mals frequently would not graze at all or and more often, than did those in Group B.