Northern Sage Grouse (Centrocercus urophasianus)
Associated Species: Other species that may use habitat in a similar way and/or respond similarly
to threats, management, and conservation activities include Brewer's Sparrow, Sage Thrasher,
Vesper Sparrow, and Sage Sparrow.
Distribution: The largest populations of Northern Sage Grouse in Colorado inhabit Jackson,
Moffat, Rio Blanco, and Routt counties with smaller populations (<500 birds) occurring in
Larimer, Grand, Eagle, Garfield, and Mesa counties. Populations in Moffat, Routt, and Jackson
counties are contiguous with populations in Utah and Wyoming.
Habitat Requirements: Northern Sage Grouse are sagebrush obligates, depending upon big
sagebrush as a primary food and as habitat for nesting, brood rearing, and roosting. They prefer
large expanses of big sagebrush on flat or gently rolling terrain, and utilize riparian meadows as
brood and summer habitat. They prefer shrub canopy cover averaging between 10% and 20% in
brood rearing areas and between 20% and 30% in adult loafing areas. They require the higher
percentages for winter habitat (Braun et al.1977). In northwestern Colorado these grouse most
commonly reside between 2400 and 2900 m (7,900-9,500 ft) elevation.
Ecology: Males begin arriving on lekking areas (strutting grounds) in March; hen attendance on
leks peaks and mating occurs in early to mid April. Strutting grounds may have 50-100 males,
although only a few dominant males perform the majority of copulations. Hens disperse up to 30
km (19 mi) for nesting, although most nest within 5 km (3 mi) of the lek where they mated.
Except for summer, when insects and forbs predominate the diet, Sage Grouse depend upon the
leaves of sagebrush for food.
Management Issues and Conservation Recommendations: Sage Grouse have been extirpated
from four states and are considered at risk in six additional states--including Colorado--and two
Canadian provinces. Long term data indicate Sage Grouse populations have declined by 33%
range-wide since the mid-1980s, and show a 31% decline in Colorado. The loss of sagebrush
habitats through burning, herbicide applications, and conversion to cropland present the greatest
threat to Sage Grouse. Additionally, excessive livestock grazing is believed to have detrimental
effects upon Sage Grouse nesting and brood-rearing habitat. Better than average grass cover is
associated with better than average nest success. Livestock loafing areas around ponds and
salting areas coinciding with leks during the spring months may remove the lek from use by
grouse. Protect and manage existing sagebrush rangeland to improve nesting and brood-rearing habitats. These improvements are critical to reversing the trends in population and
productivity. Restore summer range conditions, and restore relatively undisturbed wet meadows
and forbs in the upland plant association.
Status and Reasons for Concern: This species has a high conservation need locally and
throughout its range. Although this species is not monitored by the BBS, data from state wildlife
agencies have documented severe population declines and loss of sagebrush habitats range-wide.
The BLM lists Sage Grouse as a Sensitive Species. This species is not on the national Watch List,
but it would qualify based on its National Partners in Flight Database scores. This species is
monitored by CDOW.
Biological Objective: Maintain or increase the distribution of this species and increase size and
productivity of all breeding populations, based on CDOW surveys.
Selected References: Andrews and Righter 1992, Braun 1995, Braun et al. 1977, Connelly and
Braun 1997, Kingery 1998.