Common swifts spend almost their entire lives in flight, only landing to breed, and their welfare in urban environments depends critically on the availability of nest sites in old buildings being lost through renovation and development.
Swift welfare in urban environments is primarily a habitat provision issue: swifts need nest sites in buildings to breed and support the next generation. When buildings are renovated without swift nest replacement, breeding pairs that have returned to the same site for years are eliminated. The welfare impact on individual swifts is loss of breeding opportunity and the extended energy expenditure of searching for alternative sites in a landscape with diminishing options. Swift conservation requires planning policy that mandates nest site replacement during renovation, and householders and developers who install swift boxes actively restore the breeding habitat that urban swift welfare depends on.