Assessing Dietary Quality of White-Tailed Deer Using Fecal Indices: Effects of Supplemental Feeding and Area

Abstract

Winter generally is considered the most stressful period for deer in northern latitudes, and prolonged consumption of poor-quality diets is often the primary factor increasing overwinter mortality. Although winter diets of white-tailed deer ( Odocoileus virginianus ) in the northern Black Hills, South Dakota, have been documented, quality of these diets is unknown. It has been suggested that low-growing vegetation and agricultural lands are important factors in maintaining deer populations in the northern Black Hills; however, this hypothesis has not been tested. Additionally, a supplemental feeding program has been initiated in some areas of the northern Black Hills, but effects of this program are unknown. We used fecal indices to monitor changes in dietary quality in five study areas (one of which contained supplemental food plots for deer) at 2-week intervals from January to March 1992 and 1993. We tested hypotheses that concentrations of fecal nitrogen (FN) and fecal phosphorus (FP) would not differ intraseasonally or among study areas. In the mild winter of 1992, concentrations of FN and FP rose ( P 0.05) but were related inversely to snow depth. Supplementally fed deer consumed higher-quality diets ( P < 0.001) than nonsupplemented animals during both years. Among nonsupplemented deer, availability of agricultural land improved quality of the winter ranges in the northern Black Hills. Fecal indices are an effective method for monitoring changes in dietary quality.