VEGETATIONAL COVER AND PREDATION OF SAGE GROUSE NESTS IN OREGON

Because of long-term declines in sage grouse (Centrocercus urophasianus) abundance and productivity in Oregon, we investigated the relationship between vegetational cover and nesting by sage grouse in 2 study areas. Medium height (40-80 cm) shrub cover was greater (P < 0.001) at nonpredated (xBAR = 41%, n = 18) and predated (xBAR = 29%, n = 106) nests than in areas immediately surrounding nests (xBAR = 15 and 10%, n = 18 and 106, nonpredated and predated, respectively) or random locations (xBAR = 8%, n = 499). Tall (> 18 cm), residual grass cover was greater (P < 0.001) at nonpredated nests (xBAR = 18%) than in areas surrounding nonpredated nests (xBAR = 6%) or random locations (xBAR = 3%). There was no difference (P > 0.05) in grass cover among predated nests, nest areas, and random sites. However, nonpredated nests had greater (P < 0.001) cover of tall, residual grasses (xBAR = 18%) and medium height shrubs (xBAR = 41%) than predated nests (xBAR = 5 and 29% for grasses and shrubs, respectively). Removal of tall grass cover and medium height shrub cover may negatively influence sage grouse productivity.