Greater Sage Grouse Ecology in Wyoming
Photos of male sage grouse displaying during mating season.

The greater sage grouse is an icon of sagebrush country. 

Project Partners

Bureau of Land Management

Wyoming Game and Fish Department

Sage-Grouse Initiative

Colorado State University

Want More Information?

Contact Cam Aldridge

970-226-9433

Importance of Sage-Grouse to Wyoming—The greater sage-grouse is an icon of sagebrush country. Not only is it a popular game species, the birds’ dramatic behaviors on their mating grounds (leks) draw birdwatchers from around the world. However, the species has undergone long-term population declines and range contractions largely resulting from habitat loss and fragmentation. Because Wyoming contains some of the largest expanses of intact sagebrush and supports a large percentage of the remaining sage-grouse populations, it plays a crucial role in the species’ survival.

Seasonal Habitats are Crucial to Sage-Grouse—Sage-grouse use different habitat types for breeding, brood-rearing, and wintering. Each of these seasonal habitats provides unique resources needed at particular times of year, without which sage-grouse reproduction and survival could be reduced. It is also important that these seasonal habitats be located near one another without significant barriers between them.

Key Findings
  • Distances sage-grouse moved between seasonal habitats varied remarkably across Wyoming, with some individuals remaining year-round in the same vicinity and others moving more than 50 km.
  • Livestock grazing may have both positive and negative effects on sage-grouse population trends, depending on the level and timing of grazing.
  • Most sage-grouse populations in Wyoming are declining, but there are some areas of high sage-grouse density where populations are stable.
  • About 75% of sage-grouse in Wyoming inhabit the protected sage-grouse core management areas for some or all of their life stages. Populations using habitats outside the core areas contribute to overall populations, yet significant population declines could occur in these unprotected areas.

Study Objectives

The overall goal of this work is to provide crucial information and tools to resource managers and land-use planners for designing effective conservation strategies to maintain ecological values of sage-grouse seasonal habitats and ensure the persistence of healthy sage-grouse populations.

  • Identify clusters of sage-grouse leks, as defined by similar biological and physical attributes, at different spatial scales (such as a single lek, a cluster of neighboring leks, or a large cluster of smaller clusters). Assess sage-grouse population trends and factors influencing the trends at different spatial scales (see below).
  • Use existing sage-grouse lek-count data (indices of population size) to develop spatial (geographically explicit) models for
    • assessing sage-grouse population trends and how the trends relate to vegetation changes in sagebrush habitats from 1985–2010; and
    • estimating population trends within both designated sage-grouse management areas and lek clusters at various spatial scales to inform decision-makers and resource managers about where and at what spatial scale (local to regional) populations are declining.
  • Compile existing radio-telemetry data from previous and ongoing sage-grouse movement studies across Wyoming to
    • assess seasonal movements of both individuals and populations; and
    • develop models for predicting seasonal habitat selection by sage-grouse across Wyoming.
  • Evaluate sage-grouse population trends in relation to variation in the timing and level (number of animals per unit of time) of grazing.
  • Model sage-grouse population dynamics to identify source and sink populations (those contributing to population increases or decreases, respectively).
Map of male sage grouse lek attendance in Wyoming, 1984-2008. Click to enlarge.

Trends in male sage-grouse lek attendance in Wyoming, 1984-2008. Darker circles indicate decreasing trends in population size and lighter circles indicate increasing trends. The middle shade indicates stable populations. Click to enlarge.

How Can This Data Be Used for Sage Grouse Conservation?

Because the number of sage-grouse attending a lek is usually greatest in early April and within 30 minutes of sunrise, population-monitoring methods typically recommend counting grouse within those narrow timeframes. However, our analyses revealed that data gathered from a wider timeframe also yield accurate estimates of population sizes and trends. In turn, using a broader timeframe could enhance lek-counting efforts. Our analysis of sage-grouse population viability across different sage-grouse management areas and lek clusters indicated that most populations in Wyoming are declining. Additionally, it was found that sage-grouse populations are more likely to persist where their densities are greatest

Our analyses of sage-grouse distribution and abundance across Wyoming indicated that 75% of the birds inhabit the State’s sage-grouse core management areas during some or all of their life stages. Moreover, although populations using habitats outside the core management areas contribute to Wyoming populations overall, significant population declines could occur outside of the protected management areas. The grazing study revealed that grazing might have both positive and negative effects on sage-grouse population trends, depending on the timing and level (number of animals per unit of time) of grazing. This outcome may reflect the sensitivity of cool-season grasses to being grazed during peak growth periods.

USGS-WLCI sage-grouse research establishes the foundation for long-term sage-grouse monitoring and conservation management in Wyoming and possibly across the species’ range. Natural resource professionals with the Bureau of Land Management, Wyoming Game and Fish Department, and other agencies are using much of the existing information and many of the products to refine sage-grouse core management areas and overall land-use planning.

Photo of female sage grouse being weighed on scale.
Photo of sage grouse nest with eggs.
Photo of sage grouse chick huddling among forbs.

Information on the distribution and abundance of sage grouse across Wyoming can be used to determine where populations are stable and where they are in decline.

Sage grouse nests may be vulnerable to many types of disturbance, including grazing and development.

Sage grouse have different habitat requirements for breeding, nesting, and brood rearing. Seasonal habitat models can help land managers plan development in a way that protects important areas for these activities.