The Greater sage grouse is the largest grouse species in North America. This bird is sexually dimorphic. Male grouse have yellow lores and patches on the back of their neck. The top of their head is grey in color. They also possess brown and buff colored upper chest, while their middle chest consists of a large white collar, hiding esophageal sacs which inflate at the courtship period. In addition, they have a notable black marking on their abdomen. Males have long tail feathers, which are tapered in shape. On the other hand, feathering of the female grouse is more cryptic, allowing them to use it as a perfect camouflage during nesting period. Their plumage is covered with gray and brown, having lower degree of white coloring, compared to males. Typically, females have gray and white colored throat. They do not possess those espophageal sacs, and their tail is somewhat shorter than that of males.
These birds are distributed across North America with their range, stretching from southern Alberta and Saskatchewan in Canada to the western United States. Their preferred habitat is sagebrush of medium-density, combined with other plants. The Greater sage grouse occur mainly in shrub-steppe and meadow-steppe areas as well as hilly terrains, adjacent to valleys.
Greater sage grouse are quite social animals, gathering in flock, consisted of hundreds of birds. The sage grouse are diurnal birds. They are efficient in flying short distances and are not fast runners, though preferring to move around primarily by walking. When facing danger, the sage grouse will usually escape, hiding or flying. The breeding season starts in spring, when the birds congregate in leks, looking for mates. They gather on the breeding ground to perform courtship rituals. During the display, they unfold the strut surrounding their tail, filling and emptying their esophageal sacs with a loud booming sound, heard at a distance of a mile. In Washington, the sage grouse populations live in the sagebrush country, generally remaining within the same areathroughout the year, except for winter months, when they move to lowlands.
Great sage grouse are predominantly herbivorous.Typically, these birds forage on the ground, consuming buds and flowers of different plants. Their usual winter diet primarily consists of sagebrush leaves, while, during the summer, the sage grouse, and especially their young, will feed upon a wide variety of insects.
They have polygynous mating system, where one male mates with a number of females. During the breeding season, which takes place in spring, males perform courtship rituals in special areas called "leks", where the female constructs the nest after mating. She typically uses grass and forbs under the sagebrush as nesting materials and cover. And when the nest is built, she lays 7-9 eggs, incubating them for 25-27 days. The Greater sage grouse rear one breed in each season. The hatchlings start flying at the age of 2-3 weeks and at 5-6 weeks old they become strong flyers. Then, after first molting, at the age of 10 to 12 weeks, young become relatively independent.
The major concerns are degradation, fragmentation and loss of their natural habitat. Large areas with sagebrush communities currently turn to croplands and pastures. In croplands, these birds are threatened by herbicides and invasion of exotic plant species, which brings to unnatural fires. In pastures, excessive livestock grazing leads to reduction of their population within their home range.
The overall estimated population of the Greater sage grouse is about 150,000 mature birds. On the IUCN Red List, the species is classified as Near Threatened (NT) with decreasing number of population.
The Greater sage grouse help maintain local sagebrush communities healthy, thus aiding other species of their habitat, such as songbirds or pronghorn.