Areas with lower bird diversity appear to have a higher number of hospital admissions related to mental health conditions, research suggests.
Experts analysed data from ebird – an online database of bird observations by citizen scientists – to estimate diversity across the US state of Michigan.
The team then combined this with hospital admissions for anxiety and mood disorders in the state.
The findings, published in the journal Geo: Geography And Environment, showed lower bird diversity to be a significant predictor of higher numbers of hospital admissions for mental health conditions, highlighting the complex relationship between the disorders and biodiversity crises.
The researchers said that while income and the presence of green spaces were the strongest predictors of anxiety and mood disorder-related admissions, there were also independent “significant associations” between mental health and bird diversity.
Lead author Dr Rachel Buxton, assistant professor at the Institute of Environmental and Interdisciplinary Sciences at Carleton University in Canada, said: “Often we consider nature as representing the amount of green space near homes or the distance to the nearest park, but the link between species diversity and health is underexplored.
“Our study shows that if species diversity can affect mental health at the severe end of the spectrum (hospitalisations), it is possible that the decline in biodiversity across the globe may be intricately connected with our anxiety and mood on a day-to-day basis.
“It is critical we take a holistic approach to our mental health and nature.
“Investing in nature should not be viewed as a luxury, but a necessity, and evaluated in the context of the support for wellbeing it offers individuals and communities living in urban or nature-scarce environments.
“Restoring and conserving diverse bird communities could be one avenue to improving mental health in cities and factored into urban restoration projects and public health policies.”
Last year, researchers from King’s College London found that watching birds or listening to birdsong was linked to mental wellbeing, with effects lasting up to eight hours.
The Institute of Psychiatry, Psychology & Neuroscience (IoPPN) team said at that time that the links between birds and mental wellbeing were not explained by co-occurring environmental factors such as the presence of trees, plants or waterways.