Greater sage-grouse Centrocercus urophasianus populations in North Dakota declined approximately 67% between 1965 and 2003, and the species is listed as a Priority Level 1 Species of Special Concern by the North Dakota Game and Fish Department. The habitat and ecology of the species at the eastern edge of its historical range is largely unknown. We investigated nest site selection by greater sage-grouse and nest survival in North Dakota during 2005 -2006. Sage-grouse selected nest sites in sagebrush Artemisia spp. with more total vegetative cover, greater sagebrush density, and greater 1-m visual obstruction from the nest than at random sites. Height of grass and shrub (sagebrush) at nest sites were shorter than at random sites, because areas where sagebrush was common were sites in low seral condition or dense clay or clay-pan soils with low productivity. Constant survival estimates of incubated nests were 33% in 2005 and 30% in 2006. Variables that described the resource selection function for nests were not those that modeled nest survival. Nest survival was positively influenced by percentage of shrub (sagebrush) cover and grass height. Daily nest survival decreased substantially when percentage of shrub cover declined below about 9% and when grass heights were less than about 16 cm. Daily nest survival rates decreased with increased daily precipitation.

Greater sage-grouse (Centrocercus urophasianus) at the western edge of the Dakotas occur in the transition zone between sagebrush and grassland communities. These mixed sagebrush (Artemisia sp.) and grasslands differ from those habitats that comprise the central portions of the sage-grouse range; yet, no information is available on winter habitat selection within this region of their distribution. We evaluated factors influencing greater sage-grouse winter habitat use in North Dakota during 2005-2006-2007 and in South Dakota during 2006-2007and 2007-2008. We captured and radio-marked 97 breeding-age females and 54 breeding-age males from 2005 to 2007 and quantified habitat selection for 98 of these birds that were alive during winter. We collected habitat measurements at 340 (177 ND, 163 SD) sagegrouse use sites and 680 random (340 each at 250 m and 500 m from locations) dependent sites. Use sites differed from random sites with greater percent sagebrush cover (14.75% use vs. 7.29% random; P < 0.001), percent total vegetation cover (36.76% use vs. 32.96% random; P 0.001), and sagebrush density (2.12 plants/m 2 use vs. 0.94 plants/m 2 random; P 0.001), but lesser percent grass cover (11.76% use vs. 16.01% random; P 0.001) and litter cover (4.34% use vs. 5.55% random; P ¼ 0.001) and lower sagebrush height (20.02 cm use vs. 21.35 cm random; P ¼ 0.13) and grass height (21.47 cm use vs. 23.21 cm random; P ¼ 0.15). We used conditional logistic regression to estimate winter habitat selection by sage-grouse on continuous scales. The model sagebrush cover þ sagebrush height þ sagebrush cover  sagebrush height (w i ¼ 0.60) was the most supported of the 13 models we considered, indicating that percent sagebrush cover strongly influenced selection. Logistic odds ratios indicated that the probability of selection by sage-grouse increased by 1.867 for every 1% increase in sagebrush cover (95% CI ¼ 1.627-2.141) and by 1.041 for every 1 cm increase in sagebrush height (95% CI ¼ 1.002-1.082). The interaction between percent sagebrush canopy cover and sagebrush height (b ¼ À0.01, SE 0.01; odds ratio ¼ 0.987 [95% CI ¼ 0.983-0.992]) also was significant. Management could focus on avoiding additional loss of sagebrush habitat, identifying areas of critical winter habitat, and implementing management actions based on causal mechanisms (e.g., soil moisture, precipitation) that affect sagebrush community structure in this region. Published 2012. This article is a U.S. Government work and is in the public domain in the USA.

No abstract

No abstract

No abstract