A new study led by Cornell Lab of Ornithology researchers at the K. Lisa Yang Center for Conservation Bioacoustics shows that monitoring and managing select bird species can provide benefits for other species within specific regions.
The research, published in the journal Conservation Biology, analyzed more than 892,000 hours of bird sounds recorded across California's Sierra Nevada to test a long-standing conservation strategy—monitoring and protecting a few surrogate species can provide information and protection for the community as a whole, what scientists call the umbrella species concept.
"We've long assumed that by monitoring one or a handful of species, we can gain insights about what's happening with many other species that use similar habitats," said lead author Kristin Brunk, a postdoctoral fellow at the Cornell Lab's K. Lisa Yang Center for Conservation Bioacoustics who is now at the University of Oslo in Norway. "But this assumption has rarely been tested at the large scales where it's often applied."
Brunk and her colleagues used advanced recording devices and artificial intelligence to study the co-occurrence of six surrogate species, including the California spotted owl and black-backed woodpecker, along with 63 other bird species across 25,000 square kilometers of forest - an area the size of Vermont. These six surrogate species were chosen because each is thought to represent a unique set of conditions that also support other species that rely on similar habitat features. For example, the presence of California spotted owl is often thought to indicate mature forests, an increasingly rare habitat type that other species such as golden-crowned kinglet, hermit warbler, and hermit thrush also rely on. The umbrella species idea suggests that protecting habitat for the spotted owl should also benefit other mature forest species.
The Yang Center's SwiftOne recording devices captured bird sounds day and night at 1,651 locations in the Sierra Nevada, while machine learning software called BirdNET—also developed at the Yang Center—helped identify species from hundreds of thousands of hours of recordings. "We're entering a new era of conservation science," said co-author Connor Wood, research faculty at the Yang Center. "These tools allow us to collect and analyze data at scales that were impossible just a few years ago."
The team found that 95% of the other forest birds they studied showed positive associations with at least one of the six surrogate species. This suggests that managing forests to promote the habitat characteristics needed by these six birds could help preserve habitat for many other species as well.
"We were really excited to see these results develop, because it's one of the first real tests of the umbrella species concept," said Wood. "It's something you learn about in introductory conservation biology classes, but until now no one has really had the data needed to actually test the theory."
"With this dataset, we were able to study not only how effective the surrogate species were, but also how their effectiveness changed over the large latitudinal gradient of the Sierra Nevada," said Brunk.
Being able to test the effectiveness of surrogate species over larger areas, the researchers said, is a key output from their research. They found that the effectiveness of the surrogate species changed depending on latitude. A bird species strongly associated with a surrogate species in the northern Sierra Nevada might show no relationship, or even a negative one, in the southern portion of the range.
"This finding has important implications for conservation," Brunk explained. "It tells us we need to be careful about assuming what works in one area will work everywhere else. The habitat needs of a species are often not stationary. They change across the species' range, and we have to think about that when we choose surrogate species to monitor. Surrogate species strategies should be assessed at the same scale at which they will be applied."
The researchers stressed that selecting the right surrogate species is also important. "A good surrogate species should be enough of a specialist that it's clearly associated with some set of conditions to provide a conservation umbrella for other species," said Wood.
The study comes at a crucial time for forest managers faced with mounting threats from climate change, severe wildfires, and limited resources. The research team hopes their findings will help forest managers make more informed decisions by understanding which species serve as reliable indicators of forest health—and where these relationships hold true—managers can better target their conservation efforts.
This study was funded by USDA Forest Service Region 5; the California Climate Investment's Forest Health Research Program (grant no. 19-RP-NEU-043); the NASA Biodiversity and Ecological Forecasting Program (grant no. 20-ECOF20-0017); the National Park Service, and the University of Wisconsin's office of the vice chancellor for research for funding this project. Our work in the K Lisa Yang Center for Conservation Bioacoustics is made possible by the generosity of K Lisa Yang to advance innovative conservation technologies to inspire and inform the conservation of wildlife and habitats. BirdNET is supported by Jake Holshuh (Cornell class of '69) and The Arthur Vining Davis Foundations. The German Federal Ministry of Education and Research is funding the development of BirdNET through the project "BirdNET+" (FKZ 01|S22072). Additionally, the German Federal Ministry of Environment, Nature Conservation and Nuclear Safety is funding the development of BirdNET through the project "DeepBirdDetect" (FKZ 67KI31040E).
Brunk, K. M., H. Anu Kramer, M. Z. Peery, S. Kahl, and C. M. Wood. (2025). Assessing spatial variability and efficacy of surrogate species at an ecosystem scale. Conservation Biology:e70058. https://conbio.onlinelibrary.wiley.com/doi/10.1111/cobi.70058
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