Common swifts nest almost exclusively in buildings and their populations have declined dramatically as modern construction and renovation removes nesting cavities, creating a welfare and conservation crisis requiring architectural solutions.
Swift conservation is one of the clearest cases where simple, low-cost architectural interventions can dramatically improve individual animal welfare and population health simultaneously. The loss of traditional nesting sites in buildings through renovation and modern construction methods has removed habitat that was so specialised that swifts cannot simply find alternatives. A swift brick or nest box installed during a building project costs less than ten pounds and can host a breeding pair for decades. Individual swift welfare is directly affected by nesting site availability — birds that cannot find sites do not breed, and colony disruption causes abandonment that results in chick death. Conservation campaigns targeting architects, developers, and planning authorities have secured swift brick mandates in some jurisdictions, demonstrating that systemic solutions are achievable at the planning and policy level.