House martins are declining migratory birds that nest on buildings, increasingly facing loss of nest sites through building renovation and changing insect availability.
House martins are dependent on human structures for nesting, having largely abandoned natural cliff and cave nest sites. Building renovation including installation of soffits and fascias, re-rendering of walls, and netting of gutters destroys active nest sites and prevents recolonization. Loss of insect availability through agricultural intensification reduces food for chicks. Nest cup artificial alternatives have shown limited success where installed correctly under appropriate eaves. Late-season chicks that have not yet built sufficient fat reserves before migration face poor survival. Pesticide exposure indirectly reduces prey availability. Climate change affects both the timing of their African wintering grounds rains and the spring emergence of insects in Europe.