Dietary Overlap Among Axis, Fallow, and Blacktailed Deer and Cattle

Abstract

Seasonal diets of native Columbian black-tailed deer (Odocoileus hemionus columbianus) and exotic axis deer (Axis axis axis), fallow deer (Dama dama dama), and cattle (Bos taurus) on Point Reyes National Seashore were determined by microhistological technique to assess their dietary overlap. Throughout the year black-tailed deer ate mostly forbs, axis deer and fallow deer ate mostly grasses and forbs, and cattle ate mostly grasses. Only a few plant species comprised most of their diets. Percent composition of food species was not related to their preference indexes. Diets of axis and fallow deer overlapped more with each other and cattle than with black-tailed deer except during the summer when the dietary overlap among all species was similar at a lower level. Comparison of seasonal diets of deer with this and other studies indicated that food consumption of deer was not limited to particular food classes.