Montana Field Guide

[From Schroeder et al. 1999] North America's largest grouse. Males 1.7-2.9 kg and 65-75 cm long, females 1.0-1.8 kg and 50-60 cm long. Both sexes with relatively long, pointed tails, feathered legs, and mottled gray-brown, buff, and black plumage. Males have a blackish-brown throat patch and an inconspicuous yellow eye comb. Both sexes have blackish bellies which contrast sharply with white under-wing coverts when birds in flight. Females appear to dip from side to side while flying.

For a comprehensive review of the conservation status, habitat use, and ecology of this and other Montana bird species, please see Marks et al. 2016, Birds of Montana.

In central Montana, males occupy leks from early March to early June with peaks in late April to early May, females attend leks mid-March to late May with peaks in early to mid-April, copulations early April to late May (Eng 1963; Wallestad 1975b; Jenni and Hartzler 1978). Nesting begins mid-April, first eggs hatch in late May with peak by first half of June (42% of nests in south-central Montana hatch prior to mid-June), hatching extends to late June and early July (Eng 1963; Wallestad 1975b; Eustace 2002). In southeastern Alberta, peak hen attendance at leks early April, incubation at first nests initiated late April to early May (mean = 3 May), second nest attempts late May to mid-June (Aldridge and Brigham 2001). Birds in north-central Montana move to wintering grounds in November, remain there until mid-March and early April (Tack et al. 2011; Smith 2013); in southwest Montana, move to wintering areas sometime in September/October, return to leks in late February (Roscoe 2002).

Female Ring-necked Pheasant (Phasianus colchicus) can possibly be confused with female or young Greater Sage-Grouse. Female pheasants have a brown belly and bare legs, female Greater Sage-Grouse have a black belly patch and feathered legs. Differ from Sharp-tailed Grouse (Tympanuchus phasianellus) in having a black belly and lacking white outer tail feathers. Hybrid Greater Sage-Grouse X Sharp-tailed Grouse infrequent across range but reported in central Montana, southeastern Alberta, western North Dakota (Eng 1971; Kohn and Kobriger 1986; Aldridge et al. 2001).

May be resident year round or make seasonal migratory movements. Seasonal movements vary greatly and depend upon a number of factors including gender, behavior, seasonal habitat quality, and weather. Movements slow (< 1 km/day) and meandering, but may be as much as 25 km in 5 days (Connelly et al. 1988; Schroeder et al. 1999).

Considered non-migratory in central Montana, though small movements (generally < 16 km) made between breeding/nesting and wintering areas; winter range of females 1046-3104 hectares, with 3/4 of daily movements < 1.2 km linear distance (Eng and Schladweiler 1972; Wallestad 1975b). Males in spring move daily up to 1.8 km from leks (Wallestad and Schladweiler 1974); distance moved by females from leks to nesting site averaged 2.5-2.8 km, ranged from < 0.8 km to > 4.8 km (Wallestad and Pyrah 1974). Daily movements of summer broods averaged 0.4-0.8 km (Wallestad 1971).

Elsewhere in Montana longer annual migratory movements reported. In Valley County, marked females moved 21.5-122.1 km between breeding grounds in southern Saskatchewan and wintering grounds south of the Milk River; once on wintering grounds females moved an aveage linear distance each day of 0.25 km but up to 2.5 km (Tack et al. 2011). Since reported to make even longer movements (lasting a month) of about 160 km due to deep snowpack on traditional wintering area, returning to breeding grounds in spring in 18 days (Smith 2013). In Beaverhead County, males departing leks often moved 30-50 km to wintering grounds, sometimes in circular route with linear distance from lek only 13-16 km (as little as 3 km), but other males moved up to 80 km between lek and wintering area, possibly crossing the continental divide into Idaho during the movement. Females usually remained within 10 km of leks where they bred, but may move > 20 km from lek to wintering area (Roscoe 2002).

Closely associated with sagebrush habitat types. Adapted to a broad mosaic throughout range, including relatively tall sagebrush (Artemisia tridentata, A. tripartita, A. cana), relatively low sagebrush (A. arbuscula, A. nova), forb-rich mosaics with low and tall sagebrush, riparian meadows, steppe, scrub willow, sagebrush savanna (with juniper, ponderosa pine, aspen). Use altered habitats, such as alfalfa, wheat, crested wheatgrass, but degree depends on association with native habitat. Leks in sites with reduced herbaceous and shrub cover surrounded by potential nesting habitat, often on broad ridgetops, grassy swales, disturbed sites, dry lake beds, cultivated fields. Nesting habitat usually in thick shrub cover dominated by sagebrush, sometimes grass or other shrub species. Brood habitat a mosaic of sagebrush, riparian meadow, greasewood, alfalfa, grain fields, rich in forbs and insects. Winter range similar to breeding range and dominated by sagebrush cover types (Schroeder et al. 1999; Crawford et al. 2004). Annual variation in habitat use in Montana similar to most surrounding areas (Dusek at al. 2002); sagebrush removal results in decline or loss of sage-grouse (Martin 1970; Wallestad 1975a; Swenson et al. 1987), as does habitat fragmentation/disturbance of sagebrush related to coal-bed natural gas energy development (Walker et al. 2007).

Leks in Montana often in clearings surrounded by sagebrush, including natural clearings, old burns, clearings around abandoned homesteads. When not on lek, males in central Montana feed and loaf predominantly where sagebrush cover is 20-50% (mean = 32%), avoid sagebrush cover < 10% (Wallestad and Schladweiler 1974; Wallestad 1975b; Dusek at al. 2002). In Beaverhead County, some males moved from leks to irrigated hayfields/wetlands with adjacent sagebrush patches, others to a variety of sagebrush habitats (Wyoming big sage, mountain big sage, three-tip sage), eventually to high elevation dense sagebrush (25-35% canopy cover) surrounded by forest (Roscoe 2002).

Females establish nests where sagebrush cover exceeds 15%, height of sagebrush averages 40.4 cm (Wallestad and Pyrah 1974). Similar results for Powder River Basin (including southeastern Montana), with average sagebrush canopy cover of 19.1% at nests; sites much more likely to be used for nesting when 75% of area within 100 m (patches of sage at least 200 m diameter) was high-density sagebrush (> 40% canopy cover) (Doherty et al. 2010); 99% of 258 nests in Phillips County established under shrubs, most of these (92%) under sagebrush (Moynahan et al. 2007). In Beaverhead County, hens nest in some cases near irrigated hayfields/wet meadows with adjacent sagebrush patches (Roscoe 2002). In southeastern Alberta, 90% of 29 nests placed under silver sage in locations where sage was taller and denser than at random: mean sage canopy cover = 32%, mean sagebrush height = 41.3 cm (Aldridge and Brigham 2002).

Brood habitat in central Montana dominated by relatively open stands of sagebrush. In one study (Peterson 1970), 100% of brood occurrences in sagebrush in June, declining to 50% by September (with corresponding increase in use of grass and greasewood); average cover of sagebrush on brood sites increased from 6% in June to 12% in August , with average height of sagebrush ranging from 40.6 cm in June to 50.8 cm in September. In a second study, (Wallestad 1971, 1975b) sagebrush cover at brood sites averaged 14% in June, 10% in August, 21% in September, with overall forb cover in two years of 17-27% and grass cover 47-51%; mean shrub heights were 17.8 cm in June, 25.4 cm in August. In Beaverhead County, Montana brood canopy cover during June-September averaged 24% shrubs (mostly sagebrush), 35% grass, 22% forbs, with average height of sagebrush 22.9-38.1 cm at brood locations (Martin 1970). In southeastern Alberta, brood habitat was in silver sagebrush denser and taller than at random: 20.9% mean sagebrush canopy cover, 32.0 cm mean sagebrush height (Aldridge and Brighan 2002).

Winter habitat in central Montana generally relatively tall, dense, and extensive sagebrush stands with 20% or greater mean canopy cover (range= 6.4-53.9%) for both feeding/loafing and roosting sites (about 78-82% of all observations fall in this cover category); height of sagebrush for feeding/loafing and roosting sites averages about 25.4 cm (Eng and Schladweiler 1972; Wallestad 1975b). More open stands used as weather moderates prior to lek formation. In Powder River Basin (including Bighorn, Rosebud, Powder River counties, Montana), use areas where sagebrush and grass >95% of total vegetation cover on landscape, with sagebrush cover averaging 75% (Doherty et al. 2008). Tall dense stands of sagebrush the primary winter habitat in Beaverhead County (Roscoe 2002).

Adults eat leaves, buds, stems, flowers, fruit, and insects, but mainly leaves year round. Do not possess a muscular gizzard so do not rely on seeds. Sagebrush essential; sagebrush dominant in late autumn, winter, and early spring, sagebrush and forbs in summer, with insects mostly a minor summer component. Juvenile diet includes a larger proportion of insects (Orthoptera, Coleoptera, Hymenoptera), especially during first three weeks of life, the importance of forbs increasing with juvenile age (Schroeder et al. 1999).

Foods of adults from central Montana (Fergus and Petroleum counties) about 97% plant matter and 3% animal matter annually (Wallestad 1975b; Wallestad et al. 1975). Include in order of annual frequency and volume the plants Artemisia tridentata, Artemisia frigida, Lactuca serriola, Tragopogon dubius, Taraxacum officinale, Grindelia squarrosa, Achillea millefolium, Trifolium repens, Melilotus officinalis, Artemisia ludoviciana, Artemisia cana, Symphyotrichum species, and Medicago sativa, and at least three orders of insects (Hymenoptera, Orthoptera, Coleoptera). Insects may comprise a substantial portion of summer diet during short time periods; remains of 94 grasshoppers (Orthoptera) found in the crop and stomach of an unaged and unsexed individual from Petroleum County in early August (Moos 1941). Adults in Beaverhead County, Montana fed during late summer (July-September) primarily on Artemisia and Taraxacum (about 80% of total volume), but also included Achillea, Antennaria, Astragalus, Erigeron, Geum, Trifolium, and grass, and traces of two orders of insects (Hymenoptera and Coleoptera) (Martin 1970).

Foods of juveniles in Petroleum County, Montana vary somewhat with age, include about 75% plant matter, 25% animal matter (Peterson 1970). Include in rough order of frequency and volume the forbs Taraxacum officianale, Tragopogon dubius, Lactuca serriola, Lepidium densiflorum, Artemesia frigida, Grindelia squarrosa, Medicago sativa, Camelina microcarpa, Achillea millefolium, and Vicia americana, the shrubs Artemisia tridentata and Rhus trilobata, the grass Triticum aestivum, and at least three orders of insects (Orthoptera, Coleoptera, Hymenoptera).

Experiencing habitat loss and population declines over much of range (Schroeder at al. 1999, 2004; Crawford et al. 2004). In Montana, mean number of males/lek quite variable during 1969-2001 but overall relatively consistent at about 30 (Dusek at al. 2002). Productivity (juveniles/100 adult females) in south-central Montana during 1962-2000 averaged 256, and ranged from means of 292 during 1962-1983, 173 during 1984-1995, 293 during 1996-2000 (Eustace 2002). Brood size of a small and marginal population in the vicinity of Bowdoin National Wildlife Refuge (Phillips County) appeared relatively stable during 1988-2001 (Prellwitz 2002).

Population fluctuations and declines especially related to loss and fragmentation of sagebrush habitat (Wallestad 1975b; Swenson et al. 1987; Schroeder at al. 1999; Crawford et al. 2004), human disturbance (Aldridge and Brigham 2003), energy development (Walker et al. 2007), diseases such as West Nile virus (Naugle et al. 2004; Moynahan et al. 2006), factors affecting nest success and juvenile survival, including severe weather (especially snow completely covering sagebrush) and predators (Wallestad 1975b; Schroeder at al 1999; Moynahan et al. 2006).

Known or suspected predators in central and south-central Montana include Golden Eagle (Aquila chrysaetos), Prairie Falcon (Falco mexicanus), bobcat (Lynx rufus), and American mink (Vison vison) on lekking adults (McGahan 1968; Hartzler 1974), Black-billed Magpie (Pica hudsonia), coyote (Canis latrans), and American badger (Taxidea taxis) on nests (Wallestad and Pyrah 1974; Wallestad 1975b). Common Raven (Corvus corax) could become a more significant predator, especially on eggs (Howe and Coates 2015), as they reoccupy their former range across eastern Montana (Marks et al. 2016). In adjacent Alberta and Saskatchewan, American Crow (Corvus brachyrhynchos) and Richardson's ground squirrel (Urocitellus richardsonii) are known nest predators (Aldridge and Brigham 2003).

Range-wide mean values (Crawford et al. 2004): clutch size = 7.5 eggs, hatchability of eggs = 94.3%, proportion of females attempting nesting = 80.8%, proportion of females attempting renesting after loss of first nest = 32.5%, nest success = 47.4%.

In north-central Montana (Phillips County), females nested 4.75 km from lek (range: 0.5-29.75 km), with median renesting distance 0.58 km from first nest. Mean clutch size = 8.3 eggs (range: 7.6-8.8) for three years. Means for first nests (three years) = 8.5, renests = 7.2, adults greater than yearlings except for renesting attempts. Mean proportion of adult females nesting = 93%, yearlings = 78% (Moynahan et al. 2007). In central Montana (Fergus and Petroleum counties), nesting occurred 2.5 km and 2.8 km from lek for adult females and yearlings, respectively (68% of all 22 nests were < 2.5 km of lek). Mean clutch size = 8.2 eggs; for adult females clutch size = 9.0 eggs (range: 7-11), for juveniles = 6.9 eggs (range:4-10); 64% of nests hatched successfully (Wallestad and Pyrah 1974; Wallestad 1975b).

Males gather at leks (strutting grounds) during spring followed by females, where breeding occurs. Average lek size (males/lek/year) across Montana during 1966-2001 ranged from 17.1 to 36.6, with 12 to 79 leks surveyed each year, at least 45/year since 1975 (Dusek et al. 2002). Both adult and subadult males perform at leks, but testis size not maximized until after appearance at lek; subadult testis size only half that of adult males, and subadult males contribute very little to annual reproductive success despite producing viable sperm (Eng 1963; Walestad 1975b). In central Montana, males gather at leks March to May, with up to 80 or more males attending a lek. Females visit one or more leks, beginning a week or more after males arrive, with as many as 115 visiting a lek at one time; mating effected early April to late May, with most copulations occurring only slightly before sunrise to an hour or two after sunrise (Eng 1963; Wallestad and Pyrah 1974; Wallestad 1975b; Hartzler 1974; Jenni and Hartzler 1978).

On September 22 2015, after review of the best available scientific and commercial information, the U.S. Fish and Wildlife Service determined that the Greater Sage-Grouse did not warrant listing protections under the Endangered Species Act at the time because the primary threats to populations had been ameliorated by conservation efforts implemented by Federal, State, and private land owners.

Additional information on the management of Greater Sage-Grouse can be found at:
U.S. Fish and Wildlife Service Species Account
Montana Fish, Wildlife, and Parks Greater Sage-Grouse Information Page
Montana Fish, Wildlife, and Parks Greater Sage-Grouse Data Layers
Montana Sage Grouse Oversight Team

In Montana, new activities proposed in Greater Sage-Grouse habitats designated as core, general, or connectivity habitats as shown in the map below must undergo review via the Department of Natural Resources and Conservation's Montana Sage Grouse Project Submittal Site

Core, Connectivity, and General Habitat