People in crowded urban areas - especially poor areas - see fewer songbirds such as tits and finches, and more potential "nuisance" birds, such as pigeons, magpies and gulls, new research shows.
The University of Exeter and the British Trust for Ornithology examined ratios of birds-to-people and found areas of high-density housing have fewer birds overall - and the birds people do see are just as likely to cause a nuisance as to make them happy.
Meanwhile, people in green and leafy suburbs see up to three and a half times more songbirds and woodpeckers - which are associated with a positive impact on human wellbeing - than birds whose behaviours can cause a nuisance.
Previous research has suggested that people living in neighbourhoods with more birds, shrubs and trees are less likely to suffer from depression, anxiety and stress.
"For most people, birds provide their most common encounter with wild animals," said research fellow Dr Daniel Cox, of the Environment and Sustainability Institute at the University of Exeter's Penryn Campus in Cornwall.
"Understanding the relationship between the numbers of birds and people is important for how we manage nature and wildlife in towns and cities to promote positive nature experiences, while minimising the potential for conflict.
"There are many ways for people to attract birds to the garden to gain positive nature experiences, not only for you and your family but also for the households around you who will also have an increased chance of seeing these birds.
"We are not saying that all individuals of species such as pigeons, gulls, crows and magpies cause problems - many will provide people with positive experiences - but the behaviours of some individuals of these species can cause problems, such as noise, mess and smell."
The study conducted extensive bird surveys across three towns in England: Milton Keynes, Luton and Bedford.
The researchers then analysed how the numbers and types of birds varied with human population density.
They looked at the ratios of birds to people of species that are generally positive for our wellbeing, such as species that can be attracted to garden bird feeders like tits and finches, and species of bird whose behaviours can cause a nuisance.
Overall, they found 1.1 birds per person that make us happy, and 0.4 birds per person whose behaviours commonly cause a nuisance.
"Many people have different favourite birds, of course, but some species are more popular than others and we all benefit from having species that we perceive positively nearby," added Dr Gavin Siriwardena of the British Trust for Ornithology.
"As well as individual people attracting birds directly by feeding them, a novel approach to planning and development could see design of green spaces to maximize interactions with the wildlife they like.
"This could mean habitats like ponds and woodland integrated with new developments, but avoiding features that support nuisance species."
The study, published in the Journal of Applied Ecology, was funded by the Natural Environment Research Council and conducted as part of the Fragments, Functions, Flows and Ecosystem Services project.
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Daniel T. C. Cox et al, Covariation in urban birds providing cultural services or disservices and people, Journal of Applied Ecology (2018). DOI: 10.1111/1365-2664.13146