Common swifts are declining as modern building practices eliminate traditional nest sites; integrating swift bricks and nest boxes reverses this trend.
Destruction of swift nest sites during building renovation or demolition causes immediate displacement and often nest failure. Individual breeding pairs lose access to sites they may have used for decades. Conservation architecture — specifying swift bricks during planning and construction — prevents this welfare cost at the design stage. Householders undertaking renovations should check for swift activity before any soffit or eave work during the swift season (May-August).