Winter habitat use by juvenile greater sage-grouse on Parker Mountain, Utah: implications for sagebrush management

Greater sage-grouse (Centrocercus urophasianus; hereafter, sage-grouse) are entirely dependent on sagebrush (Artemisia spp.) for food and cover during winter. Loss or fragmentation of important wintering areas could have a disproportionate affect on population size. We radio-marked and monitored 91 juvenile sage-grouse in south-central Utah from 2008 to 2010. Thirty-four individuals survived to winter (January to March) and were used to evaluate winter habitat use. Resource use was calculated using kernel density estimation of radio-marked individuals and compared to available habitat using a G-test. We found that juvenile sage-grouse used winter habitats characterized by 0 to 5% slopes regardless of aspect and slopes 5 to 15% with south-to-west facing aspects. The importance of high slope (5 to 15%) wintering habitats has not been previously documented in sage-grouse. Most winter use was on a small proportion (3%; 2,910 ha) of available habitat. Important wintering habitats may not be readily identifiable in typical years, and consequently, due to their elevation, may be more susceptible to land management treatments focused on increasing early season livestock or big game winter forage, rendering them unsuitable for winter use by sage-grouse. Prior to implementing land management treatments in lower elevation sagebrush sites with slopes ≤5% regardless of aspect and slopes 5 to 15% south to west in aspect, managers should consider the potential effects of such treatments on the availability of suitable winter habitat to mitigate against winters with above-normal snowfall