Birds ‘sing’ to mark and defend their space, but to the human ear their territorial twittering is an aural tonic that can considerably boost wellbeing, even from a recording, a new study has confirmed.

While a growing body of research has shown that time spent in the natural world benefits human health, few studies have explored the reasons why.

A new piece of research by a team at the California Polytechnic State University sought to investigate the role the sound of birdsong plays in how people perceive their overall experience and assess their own well being while in areas away from human environments.

"There is a lot of evidence that spending time in nature has positive effects on human well-being. However, few studies have considered the specific qualities of nature that confer these benefits," said biology graduate student Danielle Ferraro, who led the study.

“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.”

Ms Ferraro and her team hid speakers which played recorded songs from a diverse group of birds on two sections of trails in the Boulder Open Space and Mountain Parks in Colorado.

The researchers alternated playing birdsong and turning the speakers off on each trail section in weekly blocks.

Hikers were interviewed after they passed through these sections.

Those who heard the additional birdsong reported a greater sense of well-being than those who didn't - even though it was a convincing recording, rather than the real thing.

The survey results showed both the sounds themselves and people's perception of biodiversity can increase 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. But 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 California Polytechnic biology professor Clinton Francis, who oversaw the research.

He said: “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.”

The scientists said the 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 bird song, they said.

“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,” Ms Ferraro said.

The research is published in Proceedings of the Royal Society B.