Diets of Wild Horses, Cattle, and Mule Deer in the Piceance Basin, Colorado

Abstract

Diets of free-roaming wild horses, domestic cattle, and mule deer were estimated for three altitudinally different vegetation zones in the Piceance Basin, northwestern Colorado. Wild horses and cattle ate mostly grasses and sedges in each of the vegetation zones. Mule deer diets consisted primarily of browse. Wild horse and cattle diets compared within a vegetation zone were more similar to each other than diets of a single herbivore compared between vegetation zones. The percentages of the diets of wild horses and cattle that were identical ranged from 59% to 75% in the three vegetation zones. Diet overlap of wild horses or cattle with mule deer was always less than 11%. The diversities of plants on the diets were lower for mule deer than for cattle or wild horses.