New publication highlights long-term IMBCR bird monitoring across the West
December 16, 2025
Conservation professionals at local, state, and federal levels agree that long-term monitoring of bird populations is critical for conservation work, but the realities are that it can be challenging to get data and population estimates that are relevant at each level: local managers may have priorities in their area that don’t match priorities– or funding– at a national level.
That’s where Integrated Monitoring in Bird Conservation Regions (IMBCR) comes in. First developed in 2008, IMBCR is the second-largest breeding bird monitoring program in North America, stretching across private and public land in the western U.S. It provides population estimates at multiple scales, from local management units like a single National Forest, up to state and region-wide, like grasslands that cross state lines. IMBCR is a collaborative partnership-based program, supported and funded by nonprofits, state, federal, and joint-ventures. This model means that no one organization bears the full cost, and also makes it easier to share information with land managers and decision makers across agencies and organizations.
Earlier this year, Christian Meny, Montana Audubon’s Director of Conservation, was a co-author on a paper that highlights IMBCR and its effectiveness. The paper, titled “Monitoring at management scales: Multi-scale trend estimates for bird populations in the western United States,” was published in the journal Ecosphere.
In some locations, there are 17 years of IMBCR data- an incredible dataset. Montana is one of three states with the longest IMBCR dataset, and Montana Audubon has been part of IMBCR for 7 years, using the protocol for bird surveys conducted on ranches as part of the Audubon Conservation Ranching program. “We adopted IMBCR protocols immediately, and use them on our larger acreage ranches,” said Meny, “and we will continue to use them going forward.”
“We participate in the IMBCR program because it is one of the, and maybe the most statistically rigorous, long-term bird surveying in the US,” he said. “With IMBCR, Montana bird data are integrated into bird data across the American West, from Montana to Arizona. Thus, we can make inferences about bird abundance, occupancy, distribution and trends across multiple spatial scales, from a single ranch, to a state, to an entire ecoregion.”
IMBCR surveys are conducted by highly trained technicians, with training in visual and aural identification of regional bird species. Montana Audubon provides multi-day training to technicians and field staff before each field season. Surveys are conducted during the breeding season, and take place between 30 minutes before sunrise and 5 hours after sunrise (technicians keep a close eye on daily sunrise times, and the extra minutes of sleep as the summer goes on are precisely counted!)
Photos from a Conservation Ranching survey on a bison ranch in Northwestern Montana.
During this survey period, a technician will conduct a six minute point count at each survey point, aiming to complete as many of the 16 points in their assigned transect as possible. Each transect consists of a 1 km2 grid with 16 survey points, each 250 m apart. During each survey, the technician will record every bird species detected (by sight, sound, or both), the distance to the bird, and the minute in which it is detected. (As one can imagine, on a busy summer’s morning on one of Montana’s grasslands, there can be a lot of frantic scribbling in the first few minutes!) At each survey point, the technician also records habitat and vegetation information, recording things like tree and shrub cover, ground cover, and average live and dead grass heights– all characteristics that are relevant to how birds may be using the habitat.
At the end of the summer breeding season, these data are carefully checked and entered into the program’s database, as well as others. “The IMBCR program, because of its rigorous design, provides high-quality data that are entered into the Montana Natural Heritage Program state library database,” said Meny. “IMBCR data give us the best picture of bird population estimates and species distribution, strongly influencing conservation status and management recommendations in the Montana Statewide Action Plan (SWAP).”
In the paper, the authors share examples of how IMBCR data can be used. In one example, they looked at population trends from 2010-2013 in Montana, Colorado, and Wyoming, to identify five species in each state showing the greatest decreasing trends; the five species showing the greatest increasing trends; and the five species that are declining the most/increasing the least on each state’s SWAP. Some caveats: the analysis only includes species for which robust trends were available, and is restricted to terrestrial songbird, gamebird, diurnal raptor, and upland nesting shorebird species– all species IMBCR is best positioned to monitor. Robust trend estimates were not available for all SWAP species.
Five most declining species in Montana for which robust trends were available, from smallest decline to largest decline: Calliope Hummingbird; Sprague’s Pipit; Spruce Grouse; Bank Swallow; Marsh Wren. Based on IMBCR population trends from 2010-2023.
Five most increasing species in Montana for which robust trends were available, from greatest increase to least increase:
Orchard Oriole; Red-headed Woodpecker; Loggerhead Shrike; Great Blue Heron; American Redstart. Based on IMBCR population trends from 2010-2023.
Five most declining or least increasing SWAP species in Montana for which robust trends were available: Declining, from greatest to least: Sprague’s Pipit; Chestnut-collard Longspur; Clark’s Nutcracker. Increasing, from least to most: Brown Creeper; Cassin’s Finch. Based on IMBCR population trends from 2010-2023.
For more examples, including using IMBCR data to identify common species in decline across the western U.S., see the full paper.
Many bird species, especially those that rely on grasslands, have been declining, and ongoing monitoring to assess population trends remains critical. Effective conservation relies on accurate long-term monitoring, and IMBCR data allows conservation managers to keep a close eye on at-risk species, as well as species that may have issues in the future. Working collaboratively, Montana Audubon contributes to this regional dataset, which allows decision makers to use the best available science to make sound conservation decisions.
