Swallows and Martins

Swallows and martins have relatively long, pointed wings, and they are swift and agile fliers. The feet of these birds tend to be small and weak, and are used for little more than perching. These birds often rest on wires and exposed branches of trees. During migration, large numbers of swallows and martins may roost together on these sorts of perches, often in mixed-species flocks. Swallows may also forage in large, mixed-species flocks during migration.

Many species of swallows and martins are rather plainly marked with dark brown or black backs and wings and a white breast. Other species are more boldly patterned, and may be brightly colored with red, yellow, and iridescent green and purple. Most species have a notched tail, and some have a deeply forked tail.

Swallows have a short but broad mouth, which can open with a very wide gape, an adaptation for catching insects on the wing. This food of flying insects is sometimes referred to as aeroplankton.

Many species of swallows and martins nest in colonies of various size, and most species are gregarious during the non-breeding season. Some swallows nest in natural or artificial cavities. Other species nest in tunnels that they dig in earthen banks. Many species construct an urn-like cavity of hardened mud or clay, or they make cup-shaped nests of these materials. The natural substrate for attachment of the constructed nests is cliffs and other sheer surfaces. However, some species use bridges and buildings as substrata upon which to build their clay nests.

All species of swallows and martins migrate between their breeding and non-breeding habitats. Species that breed at high latitudes can migrate great distances, for example, about 6,831 mi (11,000 km) in the case of the European swallow (Hirundo rustica), some of which breed in northern Europe and winter in South Africa.