Abstract - Food Habits of Deer in the Southern Black Hills as Determined by the Point Technique
Schenck, Theron II. 1971. Food Habits of Deer in the Southern Black Hills as Determined by the Point Technique. M.S. Thesis. South Dakota State University. 46 p.
White-tailed (Odocoileus virginianus) and mule deer (Odocoileus hemionius) were collected in 1968 and 1969 for a study of food habits. Rumen contents were analyzed by use of the point-analysis technique and weights. This is the first food habits study from the southern Black Hills and is necessary for proper deer management.
To evaluate the suitability of the point technique for Black Hills vegetation, an artificial population was constructed from known weights of a forb (Achillea lanulosa), grass (Oryzopsis asperfolia), rose (Rosa sp.) kinnikinnick (Arctostaphylos uva-ursi), and ponderosa pine (Pinus ponderosa). Each population was tested with 100-point trials and 200-point trials. Comparisons of point percentages to weight percentages were: forb - 24.3 to 14.8, grass - 26.5 to 25.7, rose - 10.2 to 10.8, kinnikinnick - 24.8 to 29.3, and pine - 16.3 to 18.3 percent. Forb estimates were significantly different (p > 0.05) using chi-square analysis. Browse, grasses and forbs were estimated with no significant differences (p > 0.05) using chi-square analysis: forbs - 23.3 to 14.8, grasses - 26.5 to 25.7 and browse 51.3 to 58.4 percent.
Twenty stomach samples were separated by hand after point analysis. Estimates of relative composition by hand separation and points for 10 major species were: mountain mahogany (Cercocarpus montanus), 15.2 to 13.7; ponderosa pine, 12.3 to 13.9; juniper (Juniperus spp.), 9.6 to 12.8; grasses, 9.4 to 10.3; kinnikinnick, 7.4 to 9.6; snowberry (Symphoricarpos spp.), 5.2 to 7.3; rose, 5.1 to 5.7; Oregon grape (Mahonia repens), 3.9 to 5.5; bedstraw (Galium sp.), 2.5 to 4.7; and old-man's bead (Usnea sp.), 4.2 to 3.8 percent. Paired "t" tests showed there was no significant difference (p > 0.05) between the estimated relative composition either by hand separation or by points. No difference in estimation between hand separation and point percentages was seen in class esimation of the hand-separated material: forbs, 11.9 to 17.8; grasses, 9.4 to 10.3; and browse, 69.1 to 58.7 percent.
Analysis of 52 rumen samples collected in the fall showed kinnikinnick, grasses, Oregon grape, snowberry (Symphoricarpos spp.), and forbs to be important food species.
Analysis of 64 rumen samples collected in the winter indicated that ponderosa pine, montain mahogany, and common juniper (Juniperus communis) were the most important food species. Other winter foods of importance were kinnikinnick, forbs, grasses, snowberry and Rocky Moutain juniper (Juniperus scopularum).
Point analysis of content in nine rumen collected in the summer showed that alfalfa (Medicago sativa), clover (Trifolim pratense), grasses and forbs were the most important foods.
Did You Know?
Fire is an important factor in protecting the prairie. Historically, fires burned across the prairie every 4 to 7 years. Fires burn the small trees that would otherwise march across the prairie and turn the grasslands to forest.