Prairie Dog Distribution in Areas Inhabited by Black-Footed Ferrets

The distribution of black-tailed prairie dog (Cynomys ludovicianus) towns was delineated in a 1490 km2study area in Mellette County, South Dakota, and was examined to determine the characteristics of black-looted ferret (Mustela nigripes) habitat. Between 1964 and 1974, black-looted ferrets were observed on 14 prairie dog towns in this area. Eighty-six prairie dog towns, located throughout the study area, were not randomly distributed; towns were paired or clumped in spatial distribution. Mean distance between a town and its nearest neighbor was 2.4 km; mean distance between a ferret-occupied town and the nearest town was similar, 2.7 km. Management recommendations are to maintain at least eight towns per township, each at least 12 ha in size. Of these eight towns, two or more should exceed 40 ha.