Sage grouse Centrocercus urophasianus were once common to abundant in Oregon, USA. During the past century, however, both distribution and numbers have declined, which prompted research that began in 1987. Previous work revealed the importance of sagebrush Artemisia spp. for many of the life-history needs of sage grouse. Little research emphasis has been placed, however, on the potential importance of herbaceous components of sage grouse habitat. Results of work in Oregon indicated that forbs are an important component of the diet of pre-laying hens and may be related to reproductive success. Several studies revealed that the amount of residual tall grass cover and medium height sagebrush were related closely to nest success. Further, forb availability influenced habitat use by hens with broods, and the amount of forbs and insects in chick diets may be related to recruitment of young. These studies indicated that forbs and residual grass cover are of substantially greater importance to sage grouse reproductive success than previously realized.
Key words: Artemisia spp, Centrocercus urophasianus, diets, herbaceous components, reproductive success, sagebrush, sage grouse
John A. Crawford, Department of Fisheries and Wildlife, Oregon State University, Corvallis, Oregon 97331, USA