Some Birdsongs Are More Pleasing to Human Ears Than Others. Higher-Pitched, Complex Calls Tend to Sound More Beautiful to Us

Certain acoustic features of their tweets strike a chord with humans, according to a new study. Researchers asked 84 participants in Germany to rate the pleasantness of vocalizations made by 123 European bird species. The Eurasian blackbird came out on top, while the western barn owl ranked last.

The findings, published in the journal Frontiers of Bird Science on September 1, expand our understanding of how humans perceive birdsong and could help inform soundscape management in urban green spaces and recreational areas. This suggests that enjoyment of birdsong is connected to something more fundamental than just knowing what you are listening to.” Kalb and colleagues already knew from previous research that bird sounds can boost human wellbeing and provide restorative benefits. In the new study, they wanted to better understand what elements made the songs pleasing, connecting “the biology of the bird’s vocalization and the psychology of human perception,” study co-author Christoph Randler, a biologist at the University of Tübingen, tells CNN’s Taylor Nicioli.

After asking the participants to rate recorded bird calls, the researchers analyzed each vocalization’s loudness, pitch, complexity and bandwidth, or the range of pitches. Then, they cross-referenced that data with the pleasantness scores. Quieter songs with a narrower bandwidth and higher pitch were considered the most pleasant, the team found.

Surprisingly, more complicated songs tended to receive higher marks. Besides the European blackbird, top-rated calls included those from the willow warbler, blackcap and mistle thrush. Meanwhile, the Egyptian goose, gray heron and peregrine falcon were ranked among avians with the least pleasing sounds.

The Eurasian blackbird was likely the creature being referenced in the Beatles’ song “Blackbird.” You can hear the species’ call towards the end of the tune. So, why do we like some birdsongs more than others? It’s possible that we prefer more variable sounds with moderate loudness and pitch because they “signal a safe, healthy and restorative environment where we can relax,” Kalb tells BBC Science Focus Magazine’s Jessica McAllen.

What’s more, prior knowledge of birds had no impact on how participants rated a song’s pleasantness, “suggesting that this really is about the acoustic features,” says Clinton Francis, an ecologist at California Polytechnic State University who wasn’t involved in the work, to Olivia Ferrari at Audubon. Still, there are many avenues for further research. For example, the authors didn’t test how a bird’s call rate might impact how we perceive its pleasantness—a constant chirping might eventually get on your nerves.