PATTERN OF NEST OCCUPANCY OF THE PRAIRIE VOLE MICROTUS-OCHROGASTER IN DIFFERENT HABITATS

Size and composition of social groups of the prairie vole, Microtus ochrogaster, were studied during October and November 1989 in alfalfa and bluegrass that are high and low food resource habitats, respectively, for this species. Similar data were also collected in February 1990 in tallgrass prairie, a very low food resource habitat for M. ochrogaster. Average social group size, prevalence of communal groups, and proportion of known philopatric offspring were similar in alfalfa and bluegrass. Group size and composition in alfalfa and bluegrass in 1989 were similar to those observed in alfalfa in the same months during 1981-1987. Social group size and prevalence of communal groups in tallgrass prairie were similar to those recorded in alfalfa during February 1981-1987. We conclude that food resource availability is not a proximate factor influencing formation of communal groups in M. ochrogaster.