Gunnison Sage-Grouse
Encyclopedia
The Gunnison Grouse, Centrocercus minimus, is a species of grouse
endemic to the United States
, where it is known as the Gunnison Sage-Grouse. It is similar to the closely related Greater Sage-Grouse in appearance but about a third smaller in size, with much thicker plumes behind the head; it also has a less elaborate courtship dance. It is restricted in range to southwestern Colorado
and extreme southeastern Utah
, with the largest population residing in the Gunnison
Basin region in Colorado. Despite being native to a country where the avifauna
generally is relatively well known, it was overlooked until the 1990s due the similarities with the Sage Grouse, and only described as a new species
in 2000—making it the first new avian species to be described from the USA since the 19th century. The description of C. minimus as a separate species is supported by a molecular study of genetic variation, showing that gene flow between the large-bodied and the small-bodied birds is absent.
Gunnison Grouse are notable for their elaborate courtship rituals. Each spring males congregate on leks and perform a "strutting display". Groups of females observe these displays and select the most attractive males to mate with. Only a few males do most of the breeding. Males perform on leks for several hours in the early morning and evening during the spring months. Leks are generally open areas adjacent to dense sagebrush
stands, and the same lek may be used by grouse for decades.
The numbers of this species are declining due to loss of habitat
; their range has shrunk in historical times. However, though petitions have been made to list the Gunnison Sage-Grouse under the Endangered Species Act
, the United States Fish and Wildlife Service
has not yet listed them.
.
Grouse
Grouse are a group of birds from the order Galliformes. They are sometimes considered a family Tetraonidae, though the American Ornithologists' Union and many others include grouse as a subfamily Tetraoninae in the family Phasianidae...
endemic to the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
, where it is known as the Gunnison Sage-Grouse. It is similar to the closely related Greater Sage-Grouse in appearance but about a third smaller in size, with much thicker plumes behind the head; it also has a less elaborate courtship dance. It is restricted in range to southwestern Colorado
Colorado
Colorado is a U.S. state that encompasses much of the Rocky Mountains as well as the northeastern portion of the Colorado Plateau and the western edge of the Great Plains...
and extreme southeastern Utah
Utah
Utah is a state in the Western United States. It was the 45th state to join the Union, on January 4, 1896. Approximately 80% of Utah's 2,763,885 people live along the Wasatch Front, centering on Salt Lake City. This leaves vast expanses of the state nearly uninhabited, making the population the...
, with the largest population residing in the Gunnison
Gunnison River
The Gunnison River is a tributary of the Colorado River, long, in the Southwest state of Colorado. It is the fifth largest tributary of the Colorado River, with a mean flow of 4320 ft³/s .-Description:...
Basin region in Colorado. Despite being native to a country where the avifauna
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
generally is relatively well known, it was overlooked until the 1990s due the similarities with the Sage Grouse, and only described as a new species
Bird species new to science
This article describes bird species new to science since 1900. Prior to the 20th century, and indeed into its early decades, the pace of discovery of new species was fast; during this period, with numerous collecting expeditions into species-rich areas not previously visited by western...
in 2000—making it the first new avian species to be described from the USA since the 19th century. The description of C. minimus as a separate species is supported by a molecular study of genetic variation, showing that gene flow between the large-bodied and the small-bodied birds is absent.
Gunnison Grouse are notable for their elaborate courtship rituals. Each spring males congregate on leks and perform a "strutting display". Groups of females observe these displays and select the most attractive males to mate with. Only a few males do most of the breeding. Males perform on leks for several hours in the early morning and evening during the spring months. Leks are generally open areas adjacent to dense sagebrush
Artemisia tridentata
Artemisia tridentata is a shrub or small tree from the family Asteraceae. Some botanists treat it in the segregate genus Seriphidium, as S. tridentatum W. A. Weber, but this is not widely followed...
stands, and the same lek may be used by grouse for decades.
The numbers of this species are declining due to loss of habitat
Habitat (ecology)
A habitat is an ecological or environmental area that is inhabited by a particular species of animal, plant or other type of organism...
; their range has shrunk in historical times. However, though petitions have been made to list the Gunnison Sage-Grouse under the Endangered Species Act
Endangered Species Act
The Endangered Species Act of 1973 is one of the dozens of United States environmental laws passed in the 1970s. Signed into law by President Richard Nixon on December 28, 1973, it was designed to protect critically imperiled species from extinction as a "consequence of economic growth and...
, the United States Fish and Wildlife Service
United States Fish and Wildlife Service
The United States Fish and Wildlife Service is a federal government agency within the United States Department of the Interior dedicated to the management of fish, wildlife, and natural habitats...
has not yet listed them.
Distribution
Gunnison Grouse occur in 7 counties in southwestern Colorado and 1 county in southeastern Utah.Timing of major life events
Males gather on the lek or strutting grounds, which are small open areas where breeding occurs, in late February to April, as soon as the lek is relatively free of snow. Only a few dominant males, usually 2, breed. After mating, the hen leaves the lek for the nesting grounds. Clutch size ranges from 6 to 8 eggs; incubation time is 25 to 27 days. sage grouse apparently have high rates of nest desertion and nest predation...