Male Bank Swallows dig burrows leading to underground nest chambers using their small beak, feet and wings. The male digs the burrow before he has a mate and then the female chooses a mate and nest by hovering in front of the burrow. Females build the nest by making a mat of straw, grasses, leaves and roots torn from the exposed bank. They breed near open habitats along rivers, streams, lakes and gravel pits where they search for flying insects.
Bank Swallows nest on artificial and natural sites with vertical sand-silt banks such as riverbanks, lake and ocean bluffs, sand/gravel mounds, aggregate quarries and road cuts. A burrow is dug into the side of these sites that leads to a nest chamber. Nest burrows are 63 cm deep on average, and are generally dug straight into the side of the bank (parallel to the ground). They nest in colonies ranging from 10 nests to nearly 2,000 nests.
Bank Swallows are very social birds and are often found with other birds when away from the nest.