Nesting ecology and associated habitats of greater sage-grouse in northwest South Dakota
Nicholas W. Kaczor, Department of Wildlife and Fisheries Sciences, South Dakota State University, Brookings, SD 57007
Greater sage-grouse (Centrocercus urophasianus) populations have declined range-wide at an overall rate of 2% per year from 1965 to 2003. Reasons for the decline are numerous, but are mainly attributed to human-induced factors (i.e., sagebrush degradation and removal, poor range management practices, oil and gas exploration, and West Nile virus infection). Sage-grouse occupy habitats at the eastern fringe of their range in western South Dakota and recent research has suggested that sagebrush obligates may not utilize habitats as predictable as core areas (e.g. central Wyoming). A 2-year study was conducted to investigate the nesting ecology and habitat selection of sage-grouse in northwestern South Dakota. Female sage-grouse were captured and radiocollared (n = 82) on traditional display grounds. Radio-marked hens were tracked to estimate nesting effort, nest success, and associated habitats. Nest initiation was 0.96 (70/73), with overall nest success of 0.46 ± 0.05 (n = 73, Program MARK); adults (≥2 yrs) were more successful (0.47 ± 0.03) than yearlings (0.42 ± 0.03). Hens selected habitats that provided more sagebrush canopy cover and nest bowl visual obstruction compared to random sites (AIC weight = 0.39). Nest success models developed in Program MARK indicated taller grass structures increased nest success (β = 0.15 SE = 0.03), and had a dramatic impact on nest success, achieving a summed AIC weight of 1.0. Management of sage-grouse on the eastern edge of their range should focus on increasing levels of sagebrush density and canopy cover while maintaining current grass structures.
Connelly, J. W., S. T. Knick, M. A. Schroeder, and S. J. Stiver. 2004. Conservation assessment of greater sage-grouse and sagebrush habitats. Western Association of Fish and Wildlife Agencies. Unpublished Report. Cheyenne, Wyoming.