Variable Acorn Crops: Responses of White-Tailed Deer and other Mast Consumers

We examined movements and behavior of female white-tailed deer (Odocoileus virginianus) relative to the acorn mast-fall from 1986 through 1989 in a mature deciduous forest in Front Royal, Virginia. Ten white-tailed deer with radiotransmitters increased their home range to incorporate acorn-producing areas during mast-fall. Consumption of acorns by deer constituted ca. 50% of foraging time during peak mast-fall; average consumption rate was 0.75 acorns/min searching. Although the number of acorns eaten by deer was correlated with mast-fall, a prolonged time was spent searching for acorns after mast-fall. Deer consumed 70% of marked acorns placed out during mast-fall, while medium-sized animals (e.g., Tamias striatus, Sciurus niger, Sciurus carolinensis) consumed 61% of acorns placed out later in autumn. We hypothesize that high densities of deer may limit populations of more mast-dependent species, particularly at low acorn-crop densities.