Abstract - Vegetation and Soils of Burrowing Owl Nest Sites in Conata Basin, South Dakota
MacCracken, James G., Uresk, Daniel W. and Hansen, Richard M. 1985. Vegetation and Soils of Burrowing Owl Nest Sites in Conata Basin, South Dakota. The Condor 87 . pp. 152-154.
Burrowing Owls (Athene cunicularia) in southwestern South Dakota frequently use the burrows of black-tailed prairie dogs (Cynomys ludovicianus) for nesting and escape cover. Coulobe (1971) emphasized the importance of understanding the role of burrow selection in relation to owl behavior, physiology, and overall ecology. He also suggested that availability of burrow sites may be the critical factor in Burrowing Owl population dynamics.
Re-use of next burrows by owls has been reported in the literature, but data are limited (Rich 1984). Previous reports indicate that from 8% to 60% of burrows previously occupied are re-used by Burrowing Owls (Wedgewood 1976, Gleason 1978). Rich (1984) reported that reuse of nest sites by Burrowing Owls in south central Idaho ranges from 23% to 49%. Rich noted that owls often abandon seemingly suitable nest sites for no apparent reason.
Prairie dog activities often result in a complete absence of vegetation around their burrows and short vegetation in the prairie dog colony (Bonham and Lerwic 1976, Hansen and Gold 1977). Vacant burrows in Conata Basin quickly revegetate with annual forbs and eventually perennial grasses completely covering the burrows (pers.observ.). Changes in vegetation on abandoned prairie dog burrows could influence burrowing Owl use. Furthermore, Coulombe (1971) suggested that the owls modify rodent burrows as nest sites. This suggests that soil characteristics may also be important in owl nesting ecology. Few studies have critically examined the characteristics of Burrowing Owl nest sites, and we know of no published data that quantify characteristics of vegetation and soils of prairie dog burrow sites that are used for nesting owls. Conata Basin, SD, offers an excellent place in which to examine Burrowing Owl nest site selection, because prairie dog poisoning programs have resulted in a large number of vacant burrows, of differing ages, which are potential nest sites for owls.
The purpose of our study was to characterize the vegetation and soils at abandoned prairie dog burrows used as nest sites by Burrowing Owls, and to compare these factors with those of adjacent unoccupied burrows.