Like a small, dark turkey, the male Gunnison Sage-Grouse fans a raised tail and puffs out a white chest to advertise its fitness. Unlike the turkey, the sage grouse also has a pair of yellow air sacs that add a dramatic popping noise to the display.
Until 2000, the Gunnison Sage-Grouse was considered part of a single species, the Sage Grouse. Recent genetic work and behavioral studies prompted ornithologists to split it into the Greater Sage-Grouse and the Gunnison Sage-Grouse, which has a severely restricted range and a tiny population.
A fairly large, ground-dwelling grouse, the Gunnison Sage-Grouse looks like a large, dark chicken. Males weigh almost twice as much as females (4.6 versus 2.4 pounds), with a longer body (22 vs. 18 inches) and wings (30 vs. 26 inches). Their plumages are also distinct. Males have a black throat, chin and belly that contrast with a white chest. In breeding plumage, males are spectacular with long wispy black plumes behind the head, large yellow patches of bare skin on the breast, yellow fleshy combs above the eye, and tail feathers intricately barred with white black and brown. The female's plumage is cryptic (made for concealment): mostly slate gray overall with complex brown, white and black markings.
Compared to the Greater Sage-Grouse, the Gunnison Sage-Grouse is smaller, with a grayer tail and bushier head plumes.
The Gunnison Sage-Grouse's current range is estimated at 10% of its historical size, and all of these territories are small patches, isolated from each other. It once ranged from southeastern Utah and southwestern Colorado southward into northeastern Arizona and northwestern New Mexico. The Gunnison Sage-Grouse is now confined to 7 islands of sagebrush in Colorado and 1 in Utah. The Gunnison basin hosts the largest population, approximately 75%. No other location sustains more than 8% of the total population.
In high montane valleys, the open landscape of the sagebrush provides year-round habitat for this grouse. Display sites (leks) are on flat openings within the brush, and hens nest in its tall, dense stands. Leks may be used for hundreds of years. Gunnison Sage-Grouse associate with a variety of sagebrush, including Big, Fringed, Low, Silver, and Three-tipped Sagebrush. Nest sites may also be located in Antelope Bitterbush and Rabbit Bush. In late summer and early fall, when the sagebrush dries, this grouse will move into moister habitats with grasses and weeds that support insects: meadows, river and stream bottoms with willows, and even agricultural fields.
Throughout the year, adult Gunnison Sage-Grouse consume the leaves and succulent stems of various species of sagebrush. The birds forage mostly at either end of the day and always on the ground, sometimes chasing insects. Prior to nesting, hens also eat many forbs: alfalfa, dandelion, clover, prairie pepperweed, prickly lettuce, vetch, and yellow salsify, among many others. Young grouse depend on insects like ants, beetles, and grasshoppers.
On an elevated lek, each male Gunnison Sage-Grouse defends a territory, with dominant males generally setting up territories in the center of the group. During courtship displays, the male inflates special throat pouches, exposing bright yellow patches of skin. Pointed tail feathers are held erect and fanned, and wispy plumes on the back of the neck and yellow combs above each eye are also raised. At the beginning of each strutting display, males take a few steps forward, and begin an elaborate series of sounds. These include hoots and coos, swishing sounds made by the wings, and loud "pops" amplified by the throat pouches. Typically, females choose a mate from a group of dominant males. Beneath a sagebrush plant, the hen creates a nest depression in soft soil and lines it with leaves, grass and her own down. For about 25 days, the female incubates 7-9 greenish eggs spotted with shades of brown. Usually within hours, the downy hatchlings leave the nest and follow the hen. She broods them, leads them to food sources, keeps them together, and watches for danger. The young feed themselves and grow very rapidly. The brood disperses in 10-12 weeks.
The Gunnison Sage-Grouse does not make a traditional migration. Depending on weather and food availability, some populations remain within a couple miles of the breeding range. Often in flocks or family groups, other populations may move up to 19 miles in fall and spring. Movements are usually slow and wandering.
Gunnison Sage-grouse Rangewide Steering Committee. 2005.
Gunnison sage-grouse rangewide conservation plan. Colorado Division of Wildlife, Denver, Colorado, USA. Accessed 4 July 2007.
Schroeder, M. A., J. R. Young, and C. E. Braun. 1999. Sage Grouse (
Centrocercus urophasianus). In
The Birds of North America, No. 425 (A. Poole and F. Gill, eds.). The Birds of North America, Inc., Philadelphia, PA.
Sibley, David Allen. 2000.
The Sibley Guide to Birds. Alfred A. Knopf, New York.
