New Study Eavesdrops on the Secret Lives of Birds

May 6, 2026

ITHACA, NY—Scientists have discovered they can eavesdrop on the secret lives of birds using networks of inexpensive microphones, revealing complex behaviors across vast wilderness areas, according to research published today in the journal Ecology. 

Previously, microphone technology that records sounds from wildlife had mostly been used to determine if a species was present in an area. Recordings could tell researchers what birds were present, but not what the birds were doing. Now, scientists from the Cornell Lab of Ornithology show that recordings of bird songs and calls can also reveal details about bird behavior that are otherwise time-consuming and difficult for scientists to observe directly in the wild. This research also demonstrates the value of using inexpensive microphones across large areas of land, helping scientists understand behavior at larger spatial scales.  

The team analyzed hundreds of thousands of hours of sounds recorded from microphones placed throughout California’s Sierra Nevada that were being used as part of an ongoing study to monitor bird diversity. This time the team turned their attention to answering a different question with the data that had already been collected to better understand how birds respond to calls from the American goshawk, a hawk that often preys on other birds. 

The team used BirdNet, a machine learning tool, to identify birds in the recordings and verified recordings of American goshawks to understand how birds respond when a goshawk calls. 

According to the study, birds called and sang less after an American goshawk called, but where along the roughly 420-mile span of the Sierra Nevada the birds lived affected how much they changed their behavior. Birds farther south in the Sierra Nevada sang and called less often in the presence of a goshawk than birds farther north. 

The team then honed in on the behavior of mountain chickadees, a small songbird. The chickadee’s ‘fee-bee’ song is used to attract mates and declare their territories and the ‘chickadee-dee’ alarm call is used to warn others of danger and to dissuade predators from attacking. The researchers thought chickadees would switch from songs to alarm calls when they heard a goshawk. What they found surprised them. 

Overall, chickadees sang more at sites with less vegetation beneath the forest canopy. After a goshawk call, they switched from territorial songs to alarm calls only at sites where understory plants were sparse. 

The team believes chickadees are making tradeoffs between defending a territory and evading predators. Territories with fewer plants beneath the trees are better for nesting but also more open to predators. 

“Monitoring birds using hundreds of microphones across the Sierra Nevada revealed subtle patterns of risk assessment that birds make based on habitat quality,” says Connor Wood, co-author and ecologist at the Cornell Lab of Ornithology. “They seem to be thinking, I’m gonna sing more here because it’s a high-value nesting site worth defending, but I’m also more exposed to predators here so if I hear a goshawk I’ll switch to alarm calls to avoid getting eaten.”

These subtle changes in behavior would be challenging for scientists to document using traditional field methods because it is often cost prohibitive to send biologists into the field to gather data across an entire mountain range. 

“We’ve shown that you can use microphones placed out in the forest with no attending human observers to study really fine-scale behaviors, at a really large spatial scale,” says Mickey Pardo, lead author and postdoctoral researcher at the Cornell Lab of Ornithology at the time of the study (now a researcher at ElephantVoices and Colorado State University).

Sound data has the potential to revolutionize what scientists can learn about birds across entire landscapes at a fraction of the cost of traditional methods. Recording devices allow scientists to collect thousands of hours of data day and night across large areas without having to send large teams of biologists into the field.   

“Understanding the behavioral aspects of birds is really important for conservation, because if we are relying on their behavior to inform our knowledge of where they are on the landscape, we need to be pretty sure that we’re interpreting their behavior the right way and sound recordings are a tool that can help,” says Wood.

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Reference: Pardo, M. A., L. Gallagher, R. Byers, J. M. Winiarksi, J. J. Keane, M. Z. Peery, and C. Wood. (2026). Passive acoustic monitoring reveals surprising patterns of avian community antipredator behavior at a landscape scale. Ecology https://doi.org/10.1002/ecy.70362

About the Cornell Lab of Ornithology

The Cornell Lab of Ornithology is a nonprofit, member-supported organization dedicated to the understanding and protection of birds, wildlife, and our shared planet through research, education, participatory science, and conservation. birds.cornell.edu

Media Contact:

Kathi Borgmann, Cornell Lab of Ornithology, (607) 254-2137, klb274@cornell.edu