UM Research Center Studies Effects of Military Noise on Sage Grouse

August 02, 2017

A male sage grouse displays on the lek.

MISSOULA – During an important chapter in the conservation of greater sage grouse, the University of Montana’s Center for Integrated Research on the Environment has been tasked with studying the effects of aircraft noise on the species.

The noise study aims to determine if the military activity has any impact on this iconic bird on the Department of Defense’s Mountain Home Air Force Base in Idaho. If so, the CIRE team will help the military conserve the species by providing them tools to avoid potential impacts while balancing Air Force mission goals.

The greater sage grouse, which is not listed as endangered, is an umbrella species, sharing a sagebrush habitat with more than 350 other kinds of wildlife, including elk, mule deer, wild sheep, pronghorn and golden eagles. Projects to enhance the sage grouse population often benefit these species as well. Sage grouse rely heavily on sagebrush for their forage, cover, nesting habitat and ultimate survival.

The greater sage grouse habitat covers 11 states: California, Colorado, Montana, Nevada, North Dakota, South Dakota, Oregon, Utah, Washington, Wyoming and Idaho. About 45 percent of the grouse’s summer habitat is on state and private lands, which often include the wetter meadows and riparian habitats essential for young chicks. Drier federal lands provide roughly half of the sage grouse’s winter habitat, where the birds mate and nest. The Bureau of Land Management and the U.S. Forest Service manage most of this habitat, as well as other federal agencies such as the Department of Defense. As of September 2014, the DOD manages 11.4 million acres that cover some of the sage grouse’s habitat.

Sage grouse habitat on Mountain Home Air Force Base

CIRE’s team will focus on the noise impacts from low-flying military aircraft on the nesting success of the sage grouse. Extreme noise from low flight and/or sonic booms in areas such as Mountain Home Air Force Base may affect wildlife by damaging hearing, increasing stress and the risk of predation, changing behavior patterns like avoiding suitable habitats and disturbing reproduction. Although the effects of aircraft noise on other species have been researched, this is the first time researchers have studied the effects on sage grouse.

“Given that sage grouse is a species of conservation concern throughout their current range, we think investigating all sources of human-related disturbance on these populations is important,” said Devin Landry, project manager of the study. “We are excited to be part of this bigger effort.”

This project has the potential to serve an important role in informing the U.S. Air Force as it drafts its natural resource management program according to a congressional mandate. Landry hopes the research will help produce a noise management program for other military bases sitting on sage grouse habitats throughout the West.

Last year, the CIRE team developed a work plan, and completed fieldwork mid-March to mid-April, including a site survey and count of the breeding sites – called leks – determining which were occupied and which were not.

“Lekking is a big part of the sage grouse mating system, and a lek doesn’t move much over space,” said Vicky Dreitz, a UM associate professor of wildlife biology, director of the Avian Science Center at UM and the co-principal investigator of the project. 

In previous years, Idaho Fish and Game has worked with Mountain Home Air Force Base to track where sage grouse lek, and the BLM also has many properties where sage grouse are monitored. They plan to share their database with the CIRE team, and Dreitz said the collaboration has provided them some of the preliminary information for their research.

During the first year of the study, the CIRE team has done in-depth analyses to learn more details about the project, such as how many nests need to be monitored. Although sage grouse productivity changes over time, sometimes it is due to other factors, such as dry seasons or increased predation.

“For a one-year project or even short-term study, it is going to be hard to determine if it is military activity, but through our collaborations we hope to help narrow down our understanding,” Dreitz said.

The CIRE team plans to tag breeding females with GPS units and combine the sage grouse location data with information on how noise from military jets dissipates across the landscape, with potential funding from the military.  

Dreitz said CIRE is an invaluable connection between researchers at the University and state and federal management agencies during a time when access to funding sources is crucial.

The Mountain Home Air Force Base sage grouse study is one of CIRE’s various natural resource projects, which identify and conserve threatened species to restore and maintain the landscape within military-owned lands.  

 “The work that CIRE does is meant to assist the military in their efforts to conserve and protect the natural resources that make our nation so valuable,” Landry said. “We are excited to work together to make the U.S. military leaders in conservation efforts across the country.”

For more information on the project, call Mona Nazeri, CIRE media information specialist, at 406-243-2617 or email mona.nazeri@mso.umt.edu.

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Contact: Mona Nazeri, media information specialist, UM Center for Integrated Research on the Environment, 406-243-2617, mona.nazeri@mso.umt.edu.