Sand martins are summer migrants that nest in sandy riverbanks and artificial sand banks. Their colonial nesting and dependence on insect prey make their welfare vulnerable to multiple threats.
Sand martin welfare is shaped by conditions across their migratory range. Poor Sahel rainfall during their African winter causes mass mortality before birds even reach the UK. Insufficient invertebrate prey during chick-rearing leads to starvation of nestlings. Colony disturbance by human activity during the nesting season (May-August) can cause mass nest abandonment. The vulnerability of entire colonies to single disturbance events - a bank erosion, a quarry operation, a single inconsiderate visitor - means welfare impacts can be simultaneous across hundreds of breeding pairs.