Sagebrush icons

Researchers gain valuable environmental knowledge by studying the sage-grouse and their habitat

Feature

by Harrison Tasoff

Illustrations by Charin Park

Tucked away in California’s high desert is an elusive bird whose fate is tightly bound to its particular habitat. The greater sage-grouse lives in, nests among and eats its namesake plant: sagebrush.

“The health of the sage-grouse population is inextricably linked to the health of the sagebrush ecosystem,” says Carol Blanchette, director of UC Santa Barbara’s Valentine Eastern Sierra Reserves in Mammoth Lakes.

UCSB’s Sierra Nevada Aquatic Research Lab (SNARL), part of that reserve, is the operations base for researchers monitoring the southwesternmost population of this charismatic bird and changes happening to the sagebrush ecosystem. This work has enhanced our understanding of the species and informed conservation efforts along the California-Nevada border.

Balloon chickens

The greater sage-grouse is a rather plump fowl, about the weight of a domestic chicken, but with a build closer to its relative, the turkey. “Their whole lives revolve around the sagebrush: They nest in it; they eat it; and they live in it,” explains Camden McMillan, a research technician with the U.S. Geological Survey (USGS). As a result, studying the grouse is a great way to understand the health of the ecosystem as a whole.

Indeed, the birds’ range mirrors that of the Great Basin sagebrush, stretching south from Saskatchewan to the extreme north of Arizona, and the western edge of the Dakotas to eastern California. Most populations intermingle, but a combination of mountains, human settlement and range restrictions has caused the population in the far southwestern limit of the species’ range to become isolated. Scientists refer to this region, spanning the California-Nevada border, as the bi-state area. The bi-state population has two strongholds: Bodie State Historic Park and the Long Valley Caldera, where SNARL is located.

The UC reserve is ideally situated for the research carried out by the USGS team monitoring this part of the bi-state sage-grouse population and the vitality of the sagebrush ecosystem in this region. “We’re across the street from the majority of the mating sites,” McMillan says. “We even have grouse behind us on this hill.”

Grouse have a remarkable mating ritual called lekking. Males gather en masse at natural clearings, called leks, and dance for the females. Each lek usually has a dominant male, the king of the dance floor, as it were. Greater sage-grouse perform by bouncing two yellow air sacs on their chests, which produces a wobbling sound that “The Sibley Guide to Birds” describes as “weird.”

Grouse typically return to the same lek sites year after year. This is a boon for research and conservation efforts, providing a clear focus for yearly counts. Scientists have monitored sage-grouse in Long Valley for more than 70 years. “Given the bird’s fidelity to lek sites and long history of inhabiting the bi-state area, it’s not unreasonable to assume they’ve utilized these same leks for hundreds if not thousands of years,” says Tracy Misiewicz, the bi-state sage-grouse communication and data coordinator for the Eastern Sierra Interpretive Association. In 2024, the largest lek in the Long Valley had 118 male grouse at its peak.

The work conducted out of SNARL is part of a multi-agency effort to monitor the bi-state sage-grouse, with input from federal and state agencies, public utilities and independent volunteers. Researchers at USGS catch and tag female grouse with radio collars so they can track the animals. This enables them to find the birds’ nests, which they monitor for the rest of the season, checking in roughly every three days. Chicks will often remain in family groups from the time they hatch in mid-spring through fall. Monitoring the birds’ reproductive success enables scientists to follow population trends, and the health of the sage-grouse population provides a good indication of the overall health of the sagebrush ecosystem.

Sunrise of a sagebrush landscape

A threatened species

A variety of factors threaten sage-grouse throughout their range. Climate change affects the sagebrush ecosystem, and the grouse that rely on it. Larger, more frequent wildfires can also wipe out the birds’ sagebrush and wet meadows habitats and food source. And human settlement and land use have placed increased stress on the species, fragmenting its habitat and disturbing its activity. Indeed, despite their size, grouse are pretty flighty birds. “In areas where there are more people, grouse tend to move out,” McMillan says.

Many of these threats interact with and amplify one another. For instance, climate change influences precipitation, fires and water use, which then affects the health and extent of sagebrush habitat. Invasive plants can muscle in on degraded habitat, exacerbating the previous challenges. What’s more, these threats vary in kind and magnitude across eastern California. “This means there is no silver bullet when it comes to protecting sage-grouse populations,” Misiewicz says.

The bi-state sage-grouse population has decreased by about 66% over the last 50 years, and its range has contracted by about 60 square miles since the mid 1990s. Recent modeling by USGS suggests that these declines have slowed considerably in the last 10 to 15 years. That’s good news. Both the federal and California governments are currently reviewing the bi-state population for listing under their respective endangered species legislation.

“USGS monitoring has been important in guiding the vast majority of land and wildlife management work in the bi-state in one way or another,” Misiewicz says. For instance, the knowledge gleaned from their work has guided the translocation of birds to bolster shrinking subpopulations. It has also helped identify key habitat for protection and informed conservation projects such as wet meadow restoration and invasive plant removal.

Researchers at the USGS recently examined sage-grouse population growth response across more than 800 sites to evaluate the effect of conservation work in the region over the course of the last decade. Count data from 57 leks, coupled with 85 unique actions, showed that conservation increased population numbers by 4.4%, on average. So, while the bi-state sage-grouse population has declined since 2012, current levels are 37.5% higher than they would have been without any conservation efforts.

“There are about 350 animal species with habitat needs that overlap with the sage-grouse,” Misiewicz says. “As a result, conservation efforts that benefit the sage-grouse have a positive impact on the sagebrush ecosystem and the many species that inhabit it.”

A changing desert landscape

Sagebrush has played a supporting role in this story so far, but it’s an iconic species in its own right. Coastal denizens may be familiar with California sagebrush, a fragrant plant with thinly divided glaucus leaves native to the region’s scrub, chaparral and woodland ecosystems. The desert sagebrushes are prescription strength compared to their coastal cousin. They boast tough leaves, a bitter taste and a pungent, medicinal aroma. These species underpin the sagebrush ecosystem, a quintessential symbol of the American West that spans over 175 million acres and can handle the hot, dry summers and freezing winters of America’s Great Basin desert.

Although the height of a shrub, sagebrush grows like a tree: slow and steady. But because of its size and location on the ground, it’s vulnerable to many kinds of disturbances, from fire to competition from invasive plants to trampling by people and animals. “Sagebrush takes a long time to recover,” says Steven Mathews-Sanchez, a wildlife biologist at USGS, “making the damage it receives that much more impactful.”

Sagebrush isn’t the only plant feeling the effects of dramatic changes happening in the West. “Many of the plants in the sagebrush ecosystem — including bitter brush, rabbit brush and sagebrush — are strongly affected by changes in the climate,” explains SNARL director Blanchette. “Temperature, rainfall and snowpack can have a great influence on when these plants flower and produce leaves and seeds.”

Tracking plant life cycles can provide insights on how an ecosystem is affected by environmental changes. A group of dedicated volunteers monitors these phenomena in specific plants in SNARL’s sagebrush community during the spring, summer and fall, then submits the data to the National Phenology Network, which makes it available to researchers.

Once a week, local citizen scientists like Anne Barrett and Sherryl Taylor collect data on the life stages of different plants at SNARL. Consistency is crucial when tracking cycles, so they use standardized guidelines provided by the national network and always return to the same individual plants week after week. They record features like the first emergence of leaves, flowers and fruits, as well as the color of foliage, the ripening of seeds, and the number of buds and berries.

For Taylor, studying phenology is one aspect of properly caring for the natural world. “We do it to help us understand what’s happening to these ecosystems,” she says.

Volunteers Anne and Sherryl collect data

Citizen scientists Anne Barrett and Sherryl Taylor collecting data.

These long-term data series are critical to scientists trying to understand environmental changes and climate trajectories. Often, their true value isn’t realized until years or decades after they’ve begun. “We’re putting toward the future a seed bank of knowledge,” Barrett says. “What we’re doing today might be used 50 years from now.” The sage-grouse will directly benefit from any of the resulting conservation insights.

“Sage-grouse are a beautiful, bizarre and unique example of the amazing animal diversity that we share this world with,” says Misiewicz. Understanding how sage-grouse make use of the sagebrush ecosystem, and how the ecosystem is responding to the changing climate, provides information critical for conserving this incredible species.