Greater prairie-chicken nest success and habitat selectionin southeastern Nebraska

Greater prairie-chickens (Tympanuchus cupido pinnatus) are reported to benefit from grasslands created through the Conservation Reserve Program (CRP). Prairie-chicken population size increased noticeably in southeastern Nebraska after >15% of county-level landscapes were converted to CRP grasslands. But, the mechanisms behind the increase in population size are not well understood, and managers and policy makers could benefit from evidence of CRP’s relative contribution to populations of prairie-chickens. Therefore, our objectives were to characterize the relations of vegetation structure and composition with prairie-chicken nest-site selection and nest survival rates at both the macrohabitat (within landscape of study site) and microhabitat (at the nest) level. We radio-marked female prairie-chickens at a study site with >15% of land enrolled in CRP in Johnson County in southeastern Nebraska. We monitored 90 nests during 2006–2007, 36 (40%) of which were successful. We compared nest sites’ macroand microhabitat characteristics with random points using discrete choice analyses, and we used logistic exposure analyses to assess the effect of habitat and other variables on nest survival. Prairie-chickens were 5.70 (95% CI: 2.60–12.48) times more likely to select cool-season CRP fields, and 5.05 (95% CI: 2.17–11.72) times more likely to select warm-season CRP fields for nesting relative to selecting rangeland. Prairie-chickens selected nest sites, relative to sites available in fields selected for nesting, with abundant grass cover and moderate levels of forb cover and standing litter. Females also selected sites at upper elevations. Nest survival was influenced by macrohabitat, microhabitat, and temporal variables; nest survival was greater in CRP fields and greatest for nests with abundant grass cover and forb cover and moderate levels of residual litter. Nest survival peaked, temporally, with nests initiated in late May. The size of the prairie-chicken population in southeastern Nebraska has increased since the landscape was modified under CRP, and the reproductive benefits that our study demonstrates could support such population-level responses. We would expect the population to continue to benefit from management that provides high quality, diverse grasslands.