Gunnison Sage-Grouse

Overview

The Gunnison Sage-Grouse is a sagebrush-obligate grouse confined to a small area of southwestern Colorado and adjacent Utah. It was only recognized as distinct from the more widespread Greater Sage-Grouse in the late 1990s, based on differences in size, plumage detail, and male display behavior. Males gather on traditional display grounds called leks each spring, inflating yellow-green air sacs on the breast while fanning a spiky, pointed tail.

Feather Identification

• Body feathers: finely mottled gray, brown, and black with dense vermiculation, giving a soft, camouflaged texture against sagebrush
• Tail feathers: narrow, stiff, and pointed with fine dark barring; the array forms a spiked fan during display, distinct from the smoother lyre or fan shapes of other grouse
• Belly: a solid blackish patch bordered by white flank feathers
• Vs. Greater Sage-Grouse: overall smaller with more filamentous, longer neck plumes (filoplumes) in displaying males and a comparatively more intricate banding pattern on the tail feathers
• Underwing/flight feathers: dark brownish-gray with little contrast, typical of ground-dwelling grouse built for short, explosive flushes rather than sustained flight

Plumage Notes

Males and females share the same cryptic mottled gray-brown pattern, but males are larger and show a solid black belly patch, a black throat, and elongated dark filoplumes projecting from the back of the neck that are especially prominent during lek displays. Females are smaller and more uniformly mottled, lacking the ornamental neck plumes. Juveniles resemble adult females. There is a single annual molt cycle typical of grouse, with body feathers replaced after the breeding season.

Habitat & Range

This species depends almost entirely on sagebrush shrublands for food, cover, and nesting, occupying a small range centered on the Gunnison Basin of Colorado with a few satellite populations nearby. It is a year-round resident that does not migrate long distances, though it may shift between winter and summer sagebrush stands at different elevations.

Behavior & Field Notes

Males perform elaborate strutting displays on communal leks at dawn, inflating breast air sacs and producing popping and swishing sounds while fanning the spiked tail. Diet consists mainly of sagebrush leaves supplemented by forbs and insects, especially for chicks. Nests are shallow scrapes on the ground concealed under sagebrush. The species is generally silent outside of the lek season aside from soft clucking contact calls, and its cryptic plumage makes it easily overlooked when not displaying.