characteristics around 31 successful and 10 unsuccessful nests were compared, successful nests had greater than average sagebrush cover surrounding the nest and were located in stands with a higher average canopy cover (27%) than unsuccessful nests (20%). The average height of sagebrush cover over all nests was as compared to an average height of in adjacent areas. During the nesting season, cocks and hens without nests use "relatively open" areas for feeding, and roost in "dense" patches of sagebrush. Brood rearing Clutch size ranges from six to eight eggs; incubation time is 25 to 27 days. Greater sage-grouse apparently have high rates of nest desertion and nest predation. Data from several sage grouse studies indicate a range of nesting success from 23.7 to 60.3%, with predation accounting for 26 to 76% of lost nests. Chicks fly by two weeks of age, although their movements are limited until they are two to three weeks old. They can sustain flight by five to six weeks of age. Juveniles are relatively independent by the time they have completed their first molt at 10 to 12 weeks of age. Diet Adults The importance of sagebrush in the diet of adult greater sage-grouse is great; numerous studies have documented its year-round use. A Montana study, based on 299 crop samples, showed that 62% of total food volume of the year was sagebrush. Between December and February, it was the only food item found in all crops. Only between June and September did sagebrush constitute less than 60% of their diet. Sage grouse select sagebrush species differentially. Greater sage-grouse in Antelope Valley, California, browsed black sagebrush more frequently than the more common big sagebrush. The browse of black sagebrush is highly preferred by greater sage-grouse in Nevada. In southeastern Idaho, black sagebrush was preferred as forage. Among the big sagebrush subspecies, basin big sagebrush is less nutritious and higher in terpenes than either mountain or Wyoming big sagebrush. Sage grouse prefer the other two subspecies to basin big sagebrush. In a common garden study done in Utah, greater sage-grouse preferred mountain big sagebrush over Wyoming and basin big sagebrush. Sage grouse lack a muscular gizzard and cannot grind and digest seeds; they must consume soft-tissue foods. Apart from sagebrush, the adult diet consists largely of herbaceous leaves, which are used primarily in late spring and summer. Additionally, greater sage-grouse use perennial bunchgrasses for food. Sage grouse