Food Habits of Four Species of Rodents on a Short-Grass Prairie in Colorado

Abstract

Food habits of four rodents (Dipodomys ordii, Onychomys leucogaster, Peromyscus maniculatus, and Spermophilus tridecemlineatus) of a short-grass prairie ecosystem in northeastern Colorado were studied in 1969 and 1970 through microscopic analysis of stomach contents. Mean per cent volumes of animal matter in diets of these rodents over the entire study were: D. ordii, 4.4 per cent; O. leucogaster, 73.9 per cent; P. maniculatus, 39.0 per cent; and S. tridecemlineatus, 44.0 per cent. The greatest amount of seasonal variation in per cent volume animal matter in the diet was in P. maniculatus. Animal matter in diets of all four species was composed almost entirely of arthropods and a few parts of vertebrates. The most common arthropods included adult and larval Coleoptera, larval Lepidoptera, and grasshoppers (except in D. ordii). Plant matter in the diets of all species included leaves, stems, and flowering parts of various species of grasses, sedges, forbs, and shrubs, seeds (unidentified), and tissues of mosses, lichens, and fungi. Seeds were the most common type of plant matter in diets of D. ordii and P. maniculatus, whereas plant matter in S. tridecemlineatus and O. leucogaster was more equally divided between seeds and nonseed parts of grasses (and sedges) and forbs. Much seasonal variation in types and relative amounts of different kinds of plant and animal matter was noted.