Mountain - Prairie Region
Endangered Species Program
|Greater Sage-Grouse Biologue|
|The sage-grouse (Centrocerus
urophasians), which was first described for science by Lewis and Clark
during their 1804 expedition, is an inhabitant of the open sagebrush plains.
It is a large, rounded-winged, ground-dwelling, chicken-like bird, up to 30
inched in length and two feet tall, weighing from two to seven pounds.
It has a long, pointed tail with legs feathered to the base of the toes.
For most of the year, the male and female are both colored a mottled brown,
black and white.
The greater is found from 4,000 to over 9,000 feet in elevation. It is a herbivore, eating soft plants, primarily sagebrush. One of the most interesting aspects about the sage-grouse is its nearly complete reliance on sagebrush. It is believed that these birds cannot survive in areas where sagebrush no longer exists.
Sagebrush is a woody shrub with silvery leaves that stay green all year. Sagebrush is easily identifiable by its sharp odor, described by pioneers on the Oregon Trail as a mixture of turpentine and camphor. Although sagebrush may seem hardy, a sagebrush community make take years to recover from fire and some range management practices. It takes years, maybe lifetimes, for sagebrush to fully grow back. In some areas of the Columbian Basin where a large fire burned 40 years ago, sagebrush has still not returned. A number of wildlife species depend on healthy sagebrush habitat, including larks, burrowing owls, long-billed curlews, sage sparrows, sage thrashers, loggerhead shrikes and pygmy rabbits.
In the summer the birds depend on sagebrush for shelter from predators, while the grass and plants under the sagebrush provide materials for nesting and high-protein insects for food, a critical diet for chicks in their first month of life. In winter, over 99 percent of their diet is sagebrush leaves and buds.
Common names for sage-grouse include: sage hen, sage fowl, sage cock, sage chicken, heath cock and heath hen. Adult sage-grouse have dark-green toes. In early fall, comb-like fringe appears alongside each of the three toes which then act as snowshoes for walking on deep snow and are shed in the spring.
Sage-grouse are found in Washington, Oregon, Idaho, Montana, North Dakota, eastern California, Nevada, Utah, western Colorado, South Dakota and Wyoming.
The males are larger and more colorful than females, and they have a black throat and bib, white feathers along the sides of the neck, and a large white ruff on the breast. Males also exhibit two large, frontally directed air sacs of olive-green skin and yellow combs. Both are enlarged during breeding display. During the spring courtship ritual, male birds are found early in the day on leks, also known as "drumming grounds." The males on leks strut and emit plopping sounds from the air sacs on their chests to attract females. They also lift and fan their tail feathers something like a peacock. The mating season generally begins at the same time each spring, but ultimately depends on weather and vegetative conditions.
Females lay a clutch of 7-8 eggs from mid-March to mid-June. Sage-grouse hens raise one brood in a season. The average life span of sage-grouse is 1 to 1½ years. However, they have been found to survive up to 10 years in the wild. In the evening until early morning, they roost on the ground. Approximately half of sage-grouse mortality is caused by predators, including coyotes, badgers, ravens and egg-eating ground squirrels.
RECENT FINDING: In Utah in the spring of 2003 it was noticed that large areas of sagebrush had died within the last few months. This included approximately one million acres, 600,000 of those acres are directly associated with wildlife. It is believed that this is the only major die-off of sage brush since white settlers arrived in the area in the mid-1800s. At this time, the elevation of the large die-off of sagebrush seems to be below 7,000 feet and involves mainly Bureau of Land Management land. The die-off is thought to be a result of the continuing stress on the plants due to the 5-year drought ongoing in Utah. In addition, most of the sagebrush is made up of older plants, with little new growth being found. If this drought continues, it is believed that next year sagebrush located at higher elevations (7,000 feet or more) will suffer similar loss. In Utah, higher elevations of sagebrush are mainly found on USDA-Forest Service lands.
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