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Centrocercus urophasianusgreater sage grouse(Also: sage grouse)

By Jeff Manchak

Geographic Range

Sage grouse are found year round as far north as SE Alberta and SW Saskatchewan. Their western limit is northern California and their eastern limit is North and South Dakota. Sage grouse are found as far south as Nevada.

(National Geographic, 1998)

Habitat

Sage grouse, as their name suggests, are always associated with some species of sagebrush (Artemisia spp.). These birds rely on sagebrush for leks, nesting sites, feeding sites, rearing sites, protection and wintering grounds. Sage grouse can be found in or near sagebrush habitats year round.

Secondary to sagebrush habitat, Sage grouse also require moist wetland and wet meadows (mesic sites) to aid in brood rearing. Thus, these areas are mostly occupied in late spring and summer.

Another habitat requirement for the Sage grouse are areas suitable for lek sites. Lek sites need to be flat areas that are relatively visible to females. They can range in size from about 0.5 ha to 4 ha and can be located on knolls and ridges. These sites are found to contain little vegetation but are always surrounded by sagebrush communties.

(Beck 1977; Eng and Schladweiler, 1972; Dalke et al., 1963; Clark and Dube, 1984; Drut et al., 1994)

Physical Description

Sage grouse are the largest of North American grouse and are sexually dimorphic.

Males have a grey crown, markings on the back of the neck and yellow lores. The upper chest is brown and buff and the middle is composed of a large white ruff concealing esophageal sacs that inflate during courtship. There is also a large black patch on the abdomen. The tail feathers of males are long and tapered with barring.

Females have more cryptic plumage enabling them to blend into the environment during nesting. They show less white coloring than the males and are mottled with gray and brown to a higher degree. They also lack the espophageal sacs that the males have. The throat of a female is predominantly gray and white. The tail of the female Sage grouse is not nearly as long as the male's.

(Alberta Environment, 2000; Aldridge, 1998)

  • Range mass
    1 to 3 kg
    2.20 to 6.61 lb
  • Average mass
    2.4 kg
    5.29 lb

Reproduction

The Sage grouse is a species that employs leks to select mates prior to reproduction (this aspect will be discussed in the next section). After the female has mated with a male on the lek, she will leave and construct a nest 2-6 metres from the lek.

Once the nest in constructed, the hen will lay 1 egg about every 1.3 days for 9 days. This usually results in the female laying 7 or 8 eggs. Laying and incubation of the eggs usually takes about 37 days.

After hatching, the females will remain with the hatched young. In about a week, a hatchling is able to fly short distances. At this time brood will move to a more mesic (wet) site where food will be more abundant. The young remain with their mother until the fall, at which time they segregate sexually into winter flocks.

The following spring, the yearlings will find a lek site and begin the process of displaying and attracting a mate.

(Aldridge, 1998; Patterson, 1952; Beck, 1977; Eng and Schladweiler, 1972)

  • Average eggs per season
    7
    AnAge
  • Average time to hatching
    26 days
    AnAge

Lifespan/Longevity

  • Average lifespan
    Status: captivity
    7 years
    AnAge

Behavior

During the winter and spring, the Sage grouse is a social species. In the winter, flocks of sexually segregated (i.e. males and females are separated into different flocks) individuals are found. In the spring, during the breeding season, the flocks recombine at lek sites where breeding occurs.

Sage grouse are generally sedentary, but over the winter months they have been known to move around seeking good sites for foraging.

Perhaps the most interesting aspect of the Sage grouse's behaviour is its breeding system. As mentioned previously, Sage grouse are a lekking species. This means that every breeding season, sexually mature individals gather at various sites. These sites are where males display to the females. The purpose of the display is to attract females and defend territories. The males whose display is most attractive to the female, will get to mate with her.

In early spring, males begin to return to the lek sites and establish territories. After a territory is established the male will begin displaying for the females. It has been found that the older and more experienced cocks attain 75-80% of the territories in a given lek site. If yearlings are able to establish territories they tend to be found on the outer areas of the lek while the older cocks are found nearer the middle. The males will remain on the leks from March to May, being most active at dawn and dusk.

Females will attend the lek for usually 2 to 3 days, during which time the female will select a male and mate only once. After the female has mated, she will leave the lek to build a nest and lay her eggs.

The display of male Sage grouse consists of struts and tail-fanning. Also, he will inflate his esophageal sac and display the olive-green gular sacs concealed under his feathers. Another component of the display is when the male flaps his drawn wings to make a "brushing" sound and releases air from his esophageal sac to make a "plopping noise" (sounding like a large rock dropped into deep water).

(Aldridge, 1998, 2000; Patterson, 1952; Gibson and Bradbury, 1986; Johnsgard, 1983)

Communication and Perception

Food Habits

Sage grouse lack a strong gizzard (an organ birds use to grind up food), as a result their diet is mainly soft foods.

When a Sage grouse is very young (i.e. less than one week old), 60% of its diet is insects. But, as the bird ages, its diet progresses from being mainly insectivorous to herbivorous. By 12 weeks of age, 5% of a young Sage grouse's diet is insects.

An adult Sage grouse therefore, will be predominantly herbivorous, selecting soft plants to consume. Sagebrush leaves (Artemisia spp.) constitute 60-80% of their diet in the summer and nearly 100% of their diet in the winter. Other plants consumed by Sage grouse include June Grass (Koeleria macrantha), Blue Gramma Grass (Bouteloua gracilis), and Western Wheatgrass (Agropyron smithii).

(Patterson, 1952; Johnsgard, 1983; Peterson, 1970)

Economic Importance for Humans: Positive

Hunting of the grouse for food and recreation has been historically important to humans.

This species of bird positively benefits humans in that it provides asthetic enjoyment for birdwatchers through observing and photographing their behavior on the lek sites.

The Sage grouse can also act a an indicator of a healthy prairie ecosystem. If the sagebrush communities in North America are in danger, the decline of the Sage grouse can inidicate this.

Conservation Status

The Canadian populations of Sage grouse (Centrocerus urophasianus urophasianus) have been listed as endangered by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC). The main cause of this listing has been attributed to loss of native prairie habitat. Presently, the committee on the Recovery of Nationally Endangered Wildlife (RENEW) of Canada is drafting a recovery plan for this species. Appart from this action, there has been little else done to aid the recovery of Sage grouse in Canada.

The status of western subspecies of Sage grouse (Centrocercus urophasianus phaios) within the United States varies. In New Mexico, Arizona, British Columbia, Nebraska, and Okalhoma it is extirpated. Populations have been designated as secure (no federal ranking) in Montana, Wyoming and Idaho. Again, the extirpation of some of these populations can be attributed to loss of native prairie habitat (i.e. sagebrush habitat).

(Aldridge, 2000; Bureau of Land Management, 2000; Alberta Environment, 2000; Braun, 1999)

Contributors

Jeff Manchak (author), University of Alberta, Cindy Paszkowski (editor), University of Alberta.

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

acoustic

uses sound to communicate

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

chemical

uses smells or other chemicals to communicate

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

tactile

uses touch to communicate

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.

savanna

A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.

visual

uses sight to communicate

References

Alberta Environment, 2000. "Alberta's Threatened Wildlife" (On-line). Accessed November 24, 2000 at http://www.gov.ab.ca/env/fw/threatsp/index.html.

Aldridge, C. 2000. Reproduction and Habitat use by Sage Grouse (Centrocercus urophasiansus urophasianus) in a Northern Fringe Population. University of Regina, Regina, SK: Thesis.

Aldridge, C. 1998. Status of the Sage Grouse (Centrocercus urophasianus urophasianus) in Alberta. Edmonton AB. 23 pp.: Alberta Environmental Protection, Wildlife Management Division, and Alberta Conservation Association, Wildlife Status Report No. 13.

Beck, T. 1977. Sage Grouse flock characteristics and habitat in winter. Journal of Wildlife Management, 41: 18-26.

Braun, C. 2000. "Western Sage Grouse Summary" (On-line). Accessed November 24, 2000 at http://www.sagegrouse.org/.

Bureau of Land Management, 2000. Review of Draft Interim Sage Grouse Guidelines. Portland, Oregon: 22. United States Department of the Interior, Bureau of Land Management.

Clark, J., L. Dube. 1984. An inventory of vegetative communities associated with Sage grouse leks in southern Alberta. Lethbridge, Alberta. 28pp: Alberta Energy and Natural Resources, Fish and Wildlife Division.

Dalke, P. 1968. Ecology, productivity and management of Sage Grouse in Idaho. Journal of Wildlife Management, 27: 810-841.

Drut, S. 1994. Brood habitat use by Sage Grouse in Oregon. Great Basin Naturalist, 54: 170-176.

Eng, R., P. Schladweiler. 1972. Sage Grouse winter movements and habitat use in central Montana. Journal of Wildlife Management, 36: 141-146.

Gibson, R., J. Bradbury. 1986. Male and female strategies on Sage Grouse leks. Pp. 379-398 in D Rubenstein, R Wrangham, eds. Ecological Aspects of Evolution. Princeton, NJ: Princeton University Press.

Johnsgard, P. 1983. The Grouse of the World. Lincolin, NE. 413pp: University of Nebraska Press.

National Geographic, 1998. Field Guide to the Birds of North America. Washington, D.C.: National Geographic.

Patterson, R. 1952. The Sage Grouse in Wyoming. Denver, CO. 341 pp: Sage Books.

Peterson, J. 1970. The food habits and summer distribution of juvenile Sage Grouse in Central Montana. Journal of Wildlife Management, 34: 147-155.

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