Swallows are adept aerialists, darting to catch flying insects. They occasionally eat berries and seeds.
Flocks perch in long rows on branches and wires.
When they nest, they usually produce 2 broods. Male and female build nest in 7 to 14 days on buildings, occasionally caves, culverts and under bridges. Swallows nest in colonies, yearlings from a first clutch often aid in feeding nestlings. Breeders tend to return to same colony. Males help incubate eggs.