The phantom chorus: birdsong boosts human well-being in protected areas

Abstract

Spending time in nature is known to benefit human health and well-being, but evidence is mixed as to whether biodiversity or perceptions of biodiversity contribute to these benefits. Perhaps more importantly, little is known about the sensory modalities by which humans perceive biodiversity and obtain benefits from their interactions with nature. Here, we used a ‘phantom birdsong chorus' consisting of hidden speakers to experimentally increase audible birdsong biodiversity during ‘on' and ‘off' (i.e. ambient conditions) blocks on two trails to study the role of audition in biodiversity perception and self-reported well-being among hikers. Hikers exposed to the phantom chorus reported higher levels of restorative effects compared to those that experienced ambient conditions on both trails; however, increased restorative effects were directly linked to the phantom chorus on one trail and indirectly linked to the phantom chorus on the other trail through perceptions of avian biodiversity. Our findings add to a growing body of evidence linking mental health to nature experiences and suggest that audition is an important modality by which natural environments confer restorative effects. Finally, our results suggest that maintaining or improving natural soundscapes within protected areas may be an important component to maximizing human experiences.

Sound and Soundscape in Restorative Natural Environments: A Narrative Literature Review

“…Hedblom et al (2014) observed that combinations of bird sounds were rated as more pleasant than the sounds of a single species, which may be linked to positive perceptions of biodiversity. This is supported by findings that locations judged to be rich in bird sound are also perceived as more restorative (Fisher et al, 2021), including when such sounds are experimentally manipulated (Ferraro et al, 2020).…”

Thinking Outside the Park: Connecting Visitors’ Sound Affect in a Nature-Based Tourism Setting with Perceptions of Their Urban Home and Work Soundscapes

“…The HPHP concept relates the variety of health benefits people derive from access to nature to how connections with nature foster greater interest in and support for protecting the health of natural ecosystems [2,3]. Within the HPHP initiative, researchers have recognized natural sounds as an important part of protected area (PA) biodiversity preservation and high-quality visitor experiences, providing numerous health benefits and the potential for increasing people's connection with nature, especially in the context of increasing urban density (UD) [4][5][6][7]. In response to urbanization and disconnects between people and nature [6,8], HPHP research has focused on ways to reconnect people living in urban environments to natural settings and their health benefits [9,10].…”

Bird population declines and species turnover are changing the acoustic properties of spring soundscapes

“…Sound confers a sense of place and is a key pathway for engaging with, and benefitting from, nature 15 . Indeed, since Rachel Carson's (1962) classic book "Silent Spring", nature's sounds have been inextricably linked to perceptions of environmental quality 16 , and the maintenance of natural soundscape integrity is increasingly being incorporated into conservation policy and action 17 .…”

“…Indeed, since Rachel Carson's (1962) classic book "Silent Spring", nature's sounds have been inextricably linked to perceptions of environmental quality 16 , and the maintenance of natural soundscape integrity is increasingly being incorporated into conservation policy and action 17 . Birds are a major contributor to natural soundscapes 18 and bird song, and song diversity in particular, plays an important role in defining the quality of nature experiences 15,[19][20][21] . Widespread reductions in both avian abundance 22 and species richness 23 , alongside increased biotic homogenisation 24 , are therefore likely to be impacting the acoustic properties of natural soundscapes and potentially reducing the quality of nature contact experiences 25 .…”

“…These acoustic indices are broadly correlated with avian species richness and abundance [30][31][32][33] but are fundamentally driven by song complexity and diversity across contributing species. They therefore describe the key factors predicted to underpin public perceptions of the quality of their nature experiences 15,[19][20][21] , with lower values of ADI, BI and H, and higher values of AEI, reflecting reduced acoustic diversity and intensity. These indices respond in a similar way when applied to constructed soundscapes generated from simulated communities varying in species richness and abundance, with both increasing abundance and species richness leading to increases in ADI, BI and H and a decrease in AEI (Figs.…”