Birds of a different feather
April 14, 2013
Although both are native to Northwest Colorado and share similarities in appearance and habitat, Columbian sharp-tailed grouse and greater sage grouse are two different birds:
■ Appearance — Greater sage grouse appear almost black on the ground and in flight. A long, pointed tail accounts for about half the length of their body. Males and females have narrow, pointed tail feathers, feathering to the base of the toes and a grayish brown, buff and black pattern on the upper parts, with lighter flanks and a dispersed black pattern on the abdomen. Adult males have blackish-brown throat feathers separated by a thin streak of white from a dark V-shaped pattern on the neck. Two large yellow-green skin sacs used in courtship displays are concealed by white breast feathers. Additionally, males have yellow eyecombs, also used during courtship displays. Female greater sage grouse don't have these special features, but generally have the same coloration as males. However, their throats are buffy with blackish markings and the lower throat and breast are barred, which presents a blackish-brown appearance in comparison to males.
Columbian sharp-tailed grouse also have distinct black V-shaped marks on the breast feathers. However, they have a frosty appearance because of white spotting on the body and wing feathers. The white spots on the wing feathers are an easy way to distinguish sharp-tails from sage grouse. Like with sage grouse, feathering occurs to the base of the toes. During the breeding season, males exhibit orange eyecombs and purple air sacs that are an integral part of the courtship ritual. Both sexes have inconspicuous crests, and the head and upper bodies have a barred, spotted white, buffy, tawny brown and black pattern. The breast and flanks have intricate, V-shaped brown markings on a white or buffy background.
■ Size — Male greater sage grouse weigh 4 to 5 pounds or more, while hens weigh 2 to 3 pounds. Columbian sharp-tailed grouse weigh about 1.5 pounds.
■ Habitat range — Columbian sharp-tailed grouse are found in Routt, Moffat and Rio Blanco counties. Greater sage grouse also are found in these areas of Colorado. A large population also exists in North Park in Jackson County, and smaller populations exist throughout northern and western Colorado.
■ Mating habits — In late winter, males begin to move to leks, which are their traditional strutting grounds. Females arrive one to two weeks later. Breeding occurs on the leks and in the adjacent sagebrush, typically from March through May. Males strut in a complex and ritualistic breeding display. Successfully bred females nest in the sagebrush laying a clutch of seven to nine eggs. The chicks hatch after about 26 days. The hen then moves her brood to moist areas in close proximity to the sagebrush. Broods usually disband after 10 to 12 weeks when the chicks grow their juvenile plumage. Males tend to segregate themselves from the broods but typically are found within 2 to 3 miles of the strutting grounds.
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Like sage grouse, sharp-tailed grouse breed on leks. Sharp-tail leks typically are located on knolls or ridge tops. An average of 14 birds display and breed on an area of about 100 feet in diameter. Males begin displaying in late March or April. The mating ritual for male sharp-tails includes stomping their feet and running in a circle to attract females. Females build a ground nest in grass or shrubs after breeding. A typical litter is 10 to 12 eggs and the hen incubates for about 23 days. Chicks are tended by the female after hatching. Broods are largely dependent for six to eight weeks and then disperse.
For both species, snow roosting is a key element for survival during the winter. In spring, the males head toward the leks and the cycle begins again.
Source: Colorado Parks and Wildlife