Sand martins are the earliest hirundine to arrive from Africa each spring and depend on vertical sandy banks for breeding colonies, making them vulnerable to bank erosion and habitat loss.
Sand martin welfare during breeding depends on stable, vertical sandy banks with appropriate soil texture for burrowing. River bank erosion from livestock poaching and winter flooding destroys colonies. Man-made sand martin towers have successfully compensated for some natural habitat loss. Arrival conditions in Africa affect individual body condition at the start of each breeding season.