Variables Influencing Food Habits of White-Tailed Deer on the George Reserve

Abstract

Food habits of white-tailed deer (Odocoileus virginianus) were studied from samples taken on the E.S. George Reserve, Michigan, between 1967 and 1974 to determine variation due to technique, season, years, sex, age, and population density. Techniques included rumen separation, rumen point frame, and fecal microhistological examination. There were significant differences in proportions of diet by forage classes between techniques. However, all techniques gave similar relative importances of forage classes. Diets varied seasonally with mixtures dominated by grasses in spring, forbs in early summer, leafy green browse in late summer, and acorns and other fruits in fall. Acorns were the most preferred foods, but other fruits were consumed in higher quantities in autumn of years of poor acorn production. Grasses predominated in winter during snow-free periods, and evergreen woody browse when snow depth exceeded 7.5 cm. However, at the lowest deer population densities winter diets were dominated by grasses and forbs even with snow cover. There was substantial year-to-year variation in forage classes consumed due to differences in food availability. There was a significant difference in acorn consumption by 2- and 3-year-old females, which was lower than that of females of other ages and of males. Lower consumption of acorns by these females was associated with higher consumption of seeds other than acorns and fruits. There was little change in food species selected with reduction of population density, but increased body weights and antler sizes suggested higher forage quality.