The greater sage-grouse is considered a rare bird species in North America. In recent decades, greater sage-grouse populations have declined dramatically due to habitat loss and fragmentation. Understanding the current status and distribution of greater sage-grouse is important for conservation efforts.
Quick Facts on Greater Sage-Grouse Rarity
Here are some key facts on the rarity of greater sage-grouse:
- Greater sage-grouse are found in 11 U.S. states and 2 Canadian provinces. Their geographic range has declined by nearly 50% since European settlement.
- Current population estimates indicate there are between 200,000 to 500,000 greater sage-grouse left globally. In the 1960s, estimates were as high as 1.6 million.
- Due to severe population declines, the U.S. Fish and Wildlife Service considered listing greater sage-grouse for protection under the Endangered Species Act but withdrew the proposal in 2015.
- Greater sage-grouse are considered a sensitive, threatened, or endangered species in 9 of the 11 states they inhabit. They are candidate species for federal protection.
- Many factors have reduced sage-grouse numbers, including habitat loss from agriculture, urbanization, wildfires, invasive species, and energy development.
- Greater sage-grouse require large, interconnected expanses of sagebrush habitat. Fragmentation of this habitat is a major threat.
While greater sage-grouse are still relatively widespread across western North America, their populations are declining and their sagebrush habitat is becoming more fragmented. Conservationists are concerned about the long-term outlook for this iconic species without significant protection efforts.
Population Trends Showing Decline
Scientists estimate that the greater sage-grouse population prior to European settlement was likely between 1 to 16 million. Current population estimates fall between 200,000 to 500,000. Exact population numbers are difficult to determine because the birds inhabit remote areas across 11 U.S. states and 2 Canadian provinces.
However, data from lek counts provides an index of relative abundance over time. Lek sites are communal breeding grounds where male sage-grouse perform mating displays for females each spring. Wildlife agencies and researchers monitor active leks each year to estimate trends.
Analysis of lek count data from 1965-2015 shows long-term declines for greater sage-grouse populations:
Time Period | Average Annual Decline |
---|---|
1965-1986 | 3.5% |
1986-2003 | 1.4% |
2003-2015 | 0.47% |
The rate of decline has slowed in recent decades. From 1965 to 1986, sage-grouse populations declined by an average of 3.5% per year. From 2003 to 2015, the average decline was less than 0.5% annually. Conservation efforts targeted at sage-grouse since the early 2000s may have helped stabilize populations.
However, scientists warn that stabilizing a declining population is not equal to recovery. Greater sage-grouse numbers are still well below historical levels and face ongoing threats. Continued conservation action is needed to protect sagebrush habitat and connectivity between populations.
Distribution and Range
The current distribution and geographic range of greater sage-grouse has contracted significantly from pre-settlement times. Greater sage-grouse once inhabited 16 U.S. states and 3 Canadian provinces. Now they are found in just 11 U.S. states and 2 Canadian provinces:
- California
- Colorado
- Idaho
- Montana
- Nevada
- North Dakota
- Oregon
- South Dakota
- Utah
- Washington
- Wyoming
- Alberta
- Saskatchewan
Four states that previously had greater sage-grouse (Arizona, Kansas, Nebraska, and Oklahoma) no longer support populations. Habitat loss and overhunting extirpated the birds from these areas.
Within their current range, greater sage-grouse distribution is also becoming increasingly fragmented. Large expanses of intact sagebrush habitat are broken apart by roads, cropland, energy development, and other human infrastructure. Sage-grouse avoid areas with noise, tall structures, and habitat intrusion. Fragmentation reduces connectivity between populations which can lead to localized extinctions.
Legal Protections and Conservation Status
Due to substantial population declines, the U.S. Fish and Wildlife Service (USFWS) considered listing greater sage-grouse for protection under the Endangered Species Act (ESA) in 2010. ESA listing would have provided the sage-grouse strong legal protections across its range.
After lengthy review, the USFWS withdrew the ESA listing proposal in 2015. The agency determined there were sufficient conservation plans and protections in place at the state and federal level to safeguard sage-grouse habitat and populations.
However, greater sage-grouse remain a species of conservation concern:
- The International Union for Conservation of Nature (IUCN) classifies greater sage-grouse as Near Threatened globally.
- At the federal level, greater sage-grouse are a Candidate Species under review for ESA listing.
- State wildlife agencies classify greater sage-grouse as Sensitive, Threatened, Endangered, or Species of Special Concern in nearly all states they inhabit.
Greater sage-grouse now have strong protections on federal lands administered by the Bureau of Land Management and U.S. Forest Service. Energy development, recreation, grazing, and other land uses are regulated under federal Sage-Grouse Conservation Plans.
State wildlife agencies also have regulations and habitat protection measures in place for greater sage-grouse. Hunting of the birds is tightly controlled or prohibited completely in most states.
While current protections appear to have slowed population declines, scientists warn more action is needed to recover sage-grouse numbers, expand habitat, and improve connectivity at the landscape level.
Threats to Greater Sage-Grouse
Multiple human-caused threats have reduced greater sage-grouse populations from their historical numbers and contracted their distribution. The loss, degradation, and fragmentation of sagebrush habitat are the primary factors in sage-grouse decline. Specific threats include:
- Agricultural conversion – Sagebrush areas converted to cropland eliminates habitat. Fragmentation from agriculture also reduces connectivity.
- Urbanization – Cities, roads, and infrastructure remove and fragment sagebrush habitat.
- Energy development – Oil and gas drilling, mining, pipelines, transmission lines, wind turbines, and associated infrastructure damage and fragment habitat.
- Wildfires – Invasive cheatgrass increases fire frequency which eliminates native sagebrush.
- Conifer encroachment – Juniper and pine woodlands expand into sagebrush due to fire suppression, reducing habitat suitability.
- Invasive species – Cheatgrass and other invasives outcompete native vegetation.
- Grazing – Improper grazing can degrade quality of sagebrush habitat.
- Disease – West Nile Virus has caused localized greater sage-grouse population crashes.
Controlling these threats on a landscape scale is challenging but critical for greater sage-grouse conservation. Protecting remaining high quality habitat and restoring degraded habitat on both public and private lands is the focus of current conservation efforts.
Importance of Sagebrush Habitat
Greater sage-grouse are considered a sagebrush obligate species. They require large expanses of healthy sagebrush habitat to survive. The birds rely on sagebrush for food, cover from predators, and nesting sites. Other plant species mixed with sagebrush provide forbs and grasses for food.
Sage-grouse also require a landscape with variation, including wet meadows, riparian areas, and openings in the sagebrush canopy. Different types of seasonal habitat must be connected for populations to access year-round.
Because greater sage-grouse depend entirely on sagebrush ecosystems, protecting and restoring this habitat type is paramount for conservation. However, sagebrush habitat has declined range-wide. Estimates suggest at least 50% of the sagebrush biome has been altered since European settlement.
The highly specific habitat needs of greater sage-grouse make them an “umbrella species” for other wildlife that depend on intact sagebrush ecosystems. Conservation efforts targeted for sage-grouse also benefit 350+ other species that share the same habitat.
Efforts to Protect Sagebrush Habitat
Federal and state agencies, private landowners, and conservation groups are working to conserve and restore the sagebrush biome for greater sage-grouse. Some of these efforts include:
- Protecting existing habitat from development through conservation easements and land acquisitions
- Restricting energy development from core habitat areas on public lands
- Removing encroaching conifers to open sagebrush areas
- Restoring native vegetation in areas overtaken by cheatgrass
- Using planned grazing systems that maintain habitat quality
- Reducing unneeded roads and fences that fragment habitat
- Restoring wet meadows, riparian zones, and other seasonal habitat components
Conservation groups have partnered with ranchers to improve grazing practices and protect private lands through easements. The Natural Resources Conservation Service’s Sage-Grouse Initiative works with private landowners on conservation projects.
On federal lands, sage-grouse habitat is protected through restrictions on energy development, grazing practices, recreation, and travel management. Wildfire fuel reduction treatments are being implemented to protect habitat.
Connecting these protected public and private lands into intact sagebrush ecosystems is a focus of conservation planning efforts. Maintaining connectivity allows sage-grouse populations to move between seasonal habitat areas and intermix genetically.
Reintroduction Efforts
Reintroducing greater sage-grouse to areas they were extirpated from is another conservation strategy being employed. Colorado, Utah, and Oregon have ongoing efforts to re-establish sage-grouse populations in restored habitat areas:
- Colorado – Sage-grouse were translocated from large populations in Wyoming and Nevada to the northwest Colorado between 2013-2016. These birds established new leks and breeding activity in the area.
- Utah – Since 2012, sage-grouse have been reintroduced to five sites in central and southern Utah. Over 800 birds have been translocated and populations are breeding at some release areas.
- Oregon – In 2019, sage-grouse were returned to the Crooked River National Grassland after an absence of over 80 years. Additional releases are planned as habitat restoration continues.
As sagebrush habitat is restored and protected, reintroduction efforts may expand the sage-grouse’s range back into parts of their historic distribution. Translocating birds from thriving populations also helps maintain genetic diversity.
Conclusion
Greater sage-grouse remain relatively rare across their range due to significant population declines over the past century. Habitat loss, fragmentation, and degradation have reduced the species distribution by an estimated 50%.
Current population estimates are between 200,000 to 500,000 birds range-wide. These numbers represent a small fraction of the estimated pre-settlement populations of 1 to 16 million greater sage-grouse.
The birds are now considered Near Threatened globally and endangered at the state level across much of their habitat. Although passage of the Endangered Species Act would provide stronger federal protections, ongoing conservation efforts on public and private lands are working to stabilize populations.
Restoring the sagebrush ecosystem by protecting habitat, improving connectivity, reducing threats, and translocating birds back to restored areas offer hope for the greater sage-grouse’s long-term survival. However, the species remains vulnerable without continued conservation action across its remaining fragmented range.