Exploring the relationship between bird diversity and anxiety and mood disorder hospitalisation rates

Natural environments provide a myriad of health benefits, yet the role of species diversity within these spaces remains underexplored. Bird diversity may yield mental health benefits for humans, through birdsong or feelings of connection to nature. In an initial effort to establish whether bird diversity may be linked with human health in a US context and to test the consistency in such trends from year to year, we combine widely available community (aka citizen) science data (eBird) estimating bird diversity across the state of Michigan with anxiety/mood disorder hospitalisation records (2008–18). We found a negative, significant association between bird species diversity and anxiety/mood disorder hospitalisations (β = −0.36, 95% CI = −0.69 to −0.04). The relationship between bird diversity and hospitalisations found at this scale is significant, given the potential for biodiversity to affect severe mental health outcomes. Thus, these initial findings should be further explored in studies with finer resolution of exposure to bird species and longitudinal or experimental designs that account for other demographic characteristics, risk factors and other neighbourhood features. If future studies confirm these findings, there are important implications for urban greening efforts, some of which are explicitly focused on increasing bird habitat.