ASSESSING DIETARY QUALITY OF WHITE-TAILED DEER USING FECAL INDEXES - EFFECTS OF SUPPLEMENTAL FEEDING AND AREA

Winter generally is considered the most stressful period for deer in n orthern latitudes, and prolonged consumption of poor-quality diets is often the primary factor increasing overwinter mortality. Although win ter diets of white-tailed deer (Odocoileus virginianus) in the norther n Black Hills, South Dakota, have been documented, quality of these di ets is unknown. It has been suggested that low-growing vegetation and agricultural lands are important factors in maintaining deer populatio ns in the northern Black Hills; however, this hypothesis has not been tested. Additionally, a supplemental feeding program has been initiate d in some areas of the northern Black Hills, but effects of this progr am are unknown. We used fecal indices to monitor changes in dietary qu ality in five study areas tone of which contained supplemental food pl ots for deer) at 2-week intervals from January to March 1992 and 1993. We tested hypotheses that concentrations of fecal nitrogen (FN) and f ecal phosphorus (FP) would not differ intraseasonally or among study a reas. In the mild winter of 1992, concentrations of FN and FP rose (P < 0.001) as spring approached. In 1993, FN and FP levels did not diffe r intraseasonally (P > 0.05) but were related inversely to snow depth. Supplementally fed deer consumed higher-quality diets (P < 0.001) tha n nonsupplemented animals during both years. Among nonsupplemented dee r, availability of agricultural land improved quality of the winter ra nges in the northern Black Hills. Fecal indices are an effective metho d for monitoring changes in dietary quality.