Stomach Content Analyses Related to Condition in Mule Deer, Guadalupe Mountains, New Mexico

Abstract

An index to the food habits of a nonmigratory mule deer (Odocoileus hemionus) population occupying a juniper-pinyon woodland, succulent-shrub, and shortgrass-shrub complex in southeastern New Mexico was provided by botanical analyses of 93 stomach content samples. Thirty-nine males and 54 females were obtained by shooting approximately 2 deer per month over a 49-month period. Of the total estimated volume of stomach contents, browse made up about 70 percent; forbs, 26; and grass and unidentified plant material the remainder. The five major food items, comprising about 64 percent of the total, were wavyleaf oak (Quercus undulata), juniper (Juniperus spp.), hairy cercocarpus (Cercocarpus breviflorus), yucca (Yucca spp.), and unidentified forbs, in order of decreasing percent volume. Juniper was the highest in total frequency with less variability and was the major item during the January-March period. Wavyleaf oak was the major item from April through December. When unusually heavy precipitation increased all forage-especially forb production in 1958-59--forbs exceeded both browse and grass components yearlong. Females of all age-classes collected during, and for several months after, this period were significantly heavier (P = 0.05) and presumably in better physical condition. This paper presents the results of botanical analyses of 93 mule deer (39 male, 54 female) stomach content samples collected by shooting about 2 deer per month from May 27, 1956, to June 25, 1960. They were collected between 5:00 AM and 11:00 PM at elevations ranging from about 4,800 to 6,800 feet and from all major vegetative types. Although there is an extensive literature on the food habits of mule deer (Dixon 1934, Robinson 1937, Cowan 1945, Martin et al. 1951:270-272, Lassen et al. 1952:213217, Linsdale and Tomich 1953:424-479, Dasmann and Blaisdell 1954, Leach 1956, Hill 1956:393-399, Lovaas 1958), there is apparently little food-habit data published on those nonmigratory mule deer populations found on extensive portions of southwestern juniper-pinyon woodland. The nonmigratory Guadalupe Mountain mule deer herd occupies about 453 square miles of a juniper-pinyon woodland, succulentshrub, and shortgrass-shrub complex within the Lincoln National Forest in portions of Eddy, Otero, and Chaves counties, New Mexico. It was one of the more heavily harvested herds in the state; harvest indices during the study period ranged from 2.6 to 5.6 deer per square mile and population density estimates, based on permanent pellet group transects, from 11 to 20 deer per square mile. Most of the plants cited in this paper were collected by the senior author and identified by Dr. P. J. Leyendecker of New Mexico State University, University Park, and Dr. Barton Warnock of Sul Ross State College, Alpine, Texas. The oaks were identified by Dr. C. H. Muller and Dr. John H. Tucker of the University of California. Voucher specimens of identified plants are on file in the herbaria of the above institutions as well as in the Game and Fish Department's collection at Santa Fe. Plant names are from the U. S. Forest Service (1958). All of the stomach content sample analyses were performed on a contract basis by Howard R. Leach and Bruce M. 'A contribution from New Mexico Federal Aid Project W-75-R.