Hirundinidae are small passerines specializing in aerial insectivory, catching insects on the wing. They are characterized by their streamlined bodies, long pointed wings, and often forked tails. Swallows and martins are found worldwide, and many species are migratory, following insect populations. They build nests in a variety of locations, including mud nests on buildings, cavities in banks, and some even use artificial nest boxes.