If you thought your morning hike was contributing to your well-being, a new Cal Poly study shows that you’re right, especially if our avian friends were singing while you strolled.

A growing body of research shows that time spent in nature contributes to human mental health. Although many studies have found that humans benefit from spending time in nature, few studies have explored why.

A Cal Poly research team investigated how much the natural sounds humans hear during their time in the great outdoors contribute to this sense of well-being. The study was published in Proceedings of the Royal Society B on Dec. 16.

“While the bigger picture of nature’s restorative properties is likely to involve multiple senses, our study is the first to experimentally manipulate a single one (sound) in the field and demonstrate its importance to human experiences in nature,” said Danielle Ferraro, a biology graduate student who led the study.

Ferraro and her teammates hid speakers that played recorded songs from a diverse group of birds on two sections of trails in the Open Space and Mountain Parks in Boulder, Colorado. The researchers alternated playing birdsong and turning off the speakers on each trail section in weekly blocks. Hikers were interviewed after they passed through these sections.

Hikers who heard the birdsongs reported a greater sense of well-being than those who didn’t. The survey results showed that both the sounds themselves and people’s perception of biodiversity can increase humans’ feelings of well-being.

On the first section of trail, hikers who heard more birdsong simply reported that they felt better but didn’t comment that they thought more birds lived along that part of the trail. Hikers who heard more birdsong on the other section said that they thought more birds lived along that section of trail, and researchers found this perception of more species was responsible for making hikers feel better.

“We’re such visual animals that we discount this modality of sound that we have,” said Cal Poly biology Professor Clinton Francis, who oversaw the research. “I’m still kind of flabbergasted that only 7-10 minutes of exposure to these sounds improved people’s well-being. It really underscores how important hearing is to us and probably to other animals.”

Both findings support the need to improve natural soundscapes within and outside of protected areas. Less human noise pollution could contribute to greater human happiness by making it easier to hear natural sounds, including birdsong.

“Our results underscore the need for park managers to reduce anthropogenic noise pollution, which is not only a cost-effective way to improve visitors' experiences but can also benefit wildlife as well,” Ferraro said.