The family Hirundinidae comprises the swallows and martins, small to medium-sized passerine birds known for their slender bodies, long pointed wings, and forked tails, adaptations that make them highly skilled aerial insectivores. They are cosmopolitan, found on every continent except Antarctica, and are especially associated with open habitats near water. Most species are migratory, traveling long distances between breeding and wintering grounds. Hirundinids typically build mud or grass nests, often on cliffs, trees, or man-made structures, and exhibit social behavior, frequently nesting in colonies. Their ecological role is significant, as they help control insect populations, and they are also valued as indicators of environmental health.