Sand martins nest in colonies in vertical sandy riverbanks and are vulnerable to erosion management, flood events, and food availability through aerial insects.
Sand martin colonies destroyed by riverbank reinforcement schemes lose established nest sites that populations depend on for breeding success. Flood events that undercut banks mid-breeding cause mass nest collapse and chick mortality. Drought conditions in African wintering areas cause high adult mortality before return to UK colonies. Aerial insect declines reduce food availability for chick provisioning. Riverbank management schemes that fail to account for sand martin requirements eliminate entire local breeding populations.