Sand martins excavate nesting burrows in sandy riverbanks and coastal cliffs, with welfare threats from bank collapse, flood disturbance, and predation.
Sand martin welfare at colonial nesting sites is subject to acute risks from bank collapse. Engineering works on rivers that destabilise banks cause the sudden destruction of entire colonies during the breeding season, killing eggs and chicks and causing nesting failure for the adults. Flood events that undermine nesting banks have the same effect. Repeated nest failure from bank instability causes welfare impacts on adults who invest breeding effort only to lose their eggs and chicks. Provision of artificial nesting banks — which are flood-proof and erosion-proof — provides welfare-stable nesting infrastructure that decouples breeding success from unpredictable bank stability. River management that considers the timing of bank works to avoid the nesting season directly prevents these welfare harms.