Sage-grouse diets change from insects and forbs in the spring and summer to 99% sagebrush leaves in the fall and winter. The following photo shows fresh contents from the crop of a juvenile sage-grouse hit on a road as it was leaving an alfalfa field in August. Note that it was full of grasshoppers.
Sage-grouse winter diet is 100 percent sagebrush.
Winter scat shows evidence of a uniquely designed digestive system that processes a diet of 100% sagebrush leaves. Terpenes contained in sagebrush leaves are segregated in the gut (cecal) and excreted separately. No other animal can live on 100% sagebrush. Sheep, elk, and antelope mix it with other vegetation.