Diet of Pronghorn in Western Kansas

Abstract

Pronghorn were common throughout most of Kansas before settlement of the region by European man. They had begun to decline in numbers, even in sparsely populated western Kansas, by 1877, and were nearly extirpated in the state by 1915. However, small herds of pronghorn persisted along the Kansas-Colorado state line, and these were augmented by herds introduced into several regions of Kansas during the years 1964-1979. The diet of the most successful population of pronghorn in western Kansas was found to consist largely of forbs in late spring, summer, and early autumn, of forbs supplemented with wheat and other dicots in late autumn and early spring, and of wheat in winter. Pronghorn are able to live and reproduce where 30% of the land is used for cultivated crops at least in part because they are able to use those crops as food during months when native foods are in short supply. The pronghorn (Antilocapra americana) was a characteristic inhabitant of the High Plains of Kansas before settlement of that region by European man (Brennan 1932). Early biologists (Allen 1874, Knox 1875) and professional trappers (Mead 1899) commented on their distribution, abundance, and seasonal movements on the plains of Kansas. However, records kept at the Fort Hays Military Reservation (Choate and Fleharty 1975) suggested that pronghorn had begun to decline in number by 1877. This decline continued until, in 1905, Lantz noted that the species was Fast disappearing in spite of a law to protect it. By 1912 the only report of pronghorn in Kansas was of three individuals seen in the southwestern corner of the state (Kellogg 1915). For the next 50 years, pronghorn were considered extirpated or extremely rare in Kansas (e.g. Cockrum 1952) although small herds periodically were seen in western counties (Nelson 1925). In 1962 the Kansas Fish and Game Commission conducted a census and located 37 pronghorn in Wallace and Sherman counties near the Colorado state line. This discovery led to formulation of plans to reestablish breeding populations of pronghorn in the state. Subsequently, the Kansas Fish and Game Commission introduced herds from Colorado, Nebraska, Wyoming, and Montana. However, much of the prairie in Kansas had been either fenced for livestock grazing or plowed for crop production, and it thus was questionable whether the dietary and habitat requirements of pronghorn could be met in a patchwork of rangeland and cultivated crops. Although the introductions have proven successful (Choate and Sexson 1980), at least in westernmost Kansas, it still is not known how the available habitat has satisfied the dietary requirements of pronghorn. The objectives of the study, therefore, were to determine the diet of the most successful population of pronghorn in Kansas, and to speculate regarding the prospect for pronghorn in the state. Authors, when the research was conducted, were graduate student in the Department of Biological Sciences, Director and Curator of Mammals for the Museum of the High Plains, and associate professor of botany, Fort Hays State University, Hays, Kansas 67601. Sexson is presently wildlife biologist for the Kansas Fish and Game Commission, Garden City, Kansas 67846. Partial financial support for this study was provided by the Kansas Fish and Game Commission. E. Swortz and F. Goodwin allowed access to their land; B.E. Dahl and G. Scott of Texas Tech University performed fecal analyses; and S.B. George, M.D. Engstrom, R.C. Dowler, and D. Price assisted with fieldwork. Manuscript received February 4, 1980. 100 97 I-----------~-----r---n--n-----------r-