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The Greater Sage Grouse
(Centrocercus urophasianus)
A male sage grouse. Notice the yellow, inflatable gular sacs. Image courtesy of the Utah Division of Wildlife Resources.
General Information
The sage grouse (Centrocercus urophasianus) is a bird that inhabits the Northwestern region of the United States and the Southwest part of Canada (Fischer et al. 1996). This bird is known for its classical lekking behavior. The lek plays an integral part in shaping other aspects of the sage grouse behavior, including its social spacing, sexual dimorphism, and reaction to predation.
Adult males weigh an average of 3-5 kg, while adult females weigh 1.5-2.5 kg, on average (Brooks 1930; Remington and Braun 1988). Adult males possess inflatable gular sacs, which consist of featherless regions of thickened skin. During the breeding season, this bare region changes from an olive color to a yellow color. The gular sacs are responsible for a visual and audio display when the sage grouse is attending the lek. Females possess analogous structures; however, female sacs are roughly half fo the diameter of male sacs (Brooks 1930).
The sage grouse is officially an endangered species in Canada and was under consideration for listing under the Endangered Species Act in the United States. However, the sage grouse did not qualify for protection under the ESA in the United States (read the press release here). Decline in sage grouse populations is attributed to the destruction and conversion of its habitat (Schroeder et al. 2004).
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