Observations on Habitat Preference of Onychomys leucogaster (Rodentia: Muridae) on the Central Great Plains

Abstract

Mammalogists who have trapped extensively on the central Great Plains have often observed that, although the northern grasshopper mouse occurs in a variety of prairie habitats, it is seldom abundant (see, for example, Bailey and Sperry, 1929:2-3). All one need do to corlfirm this observation is scan the lists of specimens examined in the faunal studies of Cockrum (1952:162, 163), Jones (1964:209-210, 212), and Armstrong (1972:213); mean numbers of specimens of Ow)chomys eXcogasteY per locality (not including localities west of the High Plains in Colorado or unspecified localities) listed by those authors are 4.6, 3.9, and 2.7, respectively. Cockrum (loc. cit )) Jones (loc. cit.), and Armstrong (loc. cit.) each listed only four localities (out of 36, 65, and 110, respectively, from which specimens had been examined) at which more than 10 northern grasshopper mice had been taken. It is no surprise, therefore, that preferences for particular habitats by this species are poorly understood. The purposes of this note are to report observations that were made on an especially dense population of O. IeZZvogaster, andX thereby, to elucidate certain aspects of habitat preference. On the nights of 13-14 August 1972, a collection of small mammals was amassed from several different habitats in Stanton County, Kansas. At a place 1 mi. N, 71/2 mi. W Manter (T. 29 S, R. 43 W, sec. 16), traps were set in a seral community (in a roadside ditch adjacent to an irrigated tield of stubble corn) in which the vegetation was comprised largely of annual sunflower (Helianthus nvgs) and hairy grama (Bogteloua hirsut). This trapline yielded two northern grasshopper mice and one specimen of Reithrodorztomys megalotis. Several additional traplines were set in a pasture in adjacent section 9. Although it was ungrazed at the time, the pasture previously had been overgrazed and was in an early stage of succession in which vegetative productivity was high and populations of insects (especially Orthoptera and Coleoptera) were notably dense. The terrain sloped gradually