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Ask any birder to name their favorite birdsong, and you’ll get a variety of answers, from the cheery, rich tunes of the Baltimore Oriole and American Robin to the more musical notes of a Wood Thrush or Bobolink. But regardless of personal preference, it’s more than likely they’ll agree with other birders on which songs they enjoy—and, as it turns out, which ones they don’t. 

According to a published last week in the journal Frontiers in Bird Science, the acoustic characteristics of birdsong that people find the most pleasing are surprisingly consistent across listeners. Perhaps less surprising, those songs come from species people often think of as especially melodious. Similarly, listeners also agreed on the qualities that make for an unappealing song.  

“It reminds us that bird vocalizations have an important dimension beyond communication between birds: They also form a major part of the soundscape experienced by humans,” study co-author Christoph Randler, a biologist at the University of Tübingen in Germany, said in an email.
 

The researchers asked 84 participants in Germany to rate recordings of 123 songs of European birds by pleasantness on a scale of one (least pleasant) to five (most pleasant). They then analyzed the acoustic characteristics of each song, including amplitude, frequency, complexity, and bandwidth. Cross-referencing these song properties with the pleasantness scores helped to pinpoint which aspects make some songs more appealing than others.

Overall, study subjects rated the Eurasian Blackbird’s song the most pleasant. Not to be confused with North America’s blackbirds, the Eurasian Blackbird is actually a , a group of birds known for their beautiful, complex songs. In fact, it’s the Eurasian Blackbird’s tune that is featured in The Beatles song “Blackbird.” 

Rounding out the top five most-pleasant songs were those of the Willow Warbler, Blackcap, Mistle Thrush, and Garden Warbler. The bottom five belonged to the Eurasian Jay, Peregrine Falcon, Gray Heron, Egyptian Goose, and Barn Owl, which is known for its hissing, screaming call.

According to the paper, the most pleasant songs were those with a higher frequency, meaning a higher-pitched sound, and a narrow bandwidth, or range. The higher-rated songs also tended to be more complex, including a variety of elements like different notes, trills, and jumps, as opposed to a more monotone tune. Lower amplitude songs, which sound quieter, were also rated more pleasant. The songs ranked least pleasant tended to be lower-pitched, less complex, and louder.

That listeners ranked complex songs more pleasant surprised Randler; simpler, more repetitive sounds seemed like they would make for easier listening. But the results show that a dash of complexity with some repetitive notes and the right balance of frequency and amplitude might form the ideal sweet spot for an appealing melody. “There appears to be a measurable acoustic structure underlying at least part of our response to birdsong,” Randler said.

The preference for a narrow bandwidth aligns with other audio research. Human hearing is especially sensitive to a certain frequency range, and songs that fall within it can sound grating. The most pleasant songs in the study fall just outside of our sensitivity range, said Clinton Francis, an ecologist at California Polytechnic State University who was not involved with the new study. 

The data also show that specialization—such as being a birder or knowing more about birds—was unrelated to perceived song pleasantness. “It’s pretty neat, suggesting that this really is about the acoustic features,” Francis said in an email.

The study’s results could also at least partially explain why feeling calmed by birdsong is a universal human experience. Natural soundscapes, especially those that feature birdsong, make us feel at ease. Studies show hearing birdsong reduces stress, alleviates anxiety and paranoia, and .

According to the study authors, the highest-rated birdsongs could be those that we perceive as signaling a safe, healthy, and restorative environment—one where we feel like we can relax. Francis agrees. “Throughout our evolutionary history, hearing birdsong has been a signal that there isn’t any danger,” he points out.

Next up, the researchers hope to conduct a similar study outside the lab to understand how these patterns might change with other noises and environmental variables. The team is also curious about how birdsong preferences might be shaped by listeners’ diverse backgrounds and cultural experiences.

Research that shows how humans benefit from nature, such as this study, is crucial to gathering support for conservation, according to Francis: “The more that we can document these benefits, we can galvanize support for wild spaces, and for people taking time to interact with nature.”

With bird biodiversity threatened around the world, species loss leaves behind a quieter soundscape. The findings can help advocates choose bird species to represent conservation campaigns, the study authors say, using pleasant songs to cultivate support for ecosystem protection that extends to all birds. “If we understand which components of biodiversity people actually perceive and value,” Randler said, “we can better understand the human side of biodiversity conservation.”