Swallows

The swallows and martins are a group of passerine birds in the family Hirundinidae which are characterised by their adaptation to aerial feeding. Swallow is used colloquially in Europe as a synonym for the Barn Swallow.

This family comprises two subfamilies: Pseudochelidoninae (the river martins of the genus Pseudochelidon) and Hirundininae (all other swallows and martins). Within the Hirundininae, the name “martin” tends to be used for the squarer-tailed species, and the name “swallow” for the more fork-tailed species; however , there is no scientific distinction between these two groups. The swallows have a cosmopolitan distribution across the world and breed on all the continents except Antarctica. It is believed that this family originated in Africa as hole-nesters; Africa still has the greatest diversity of species. They also occur on a number of oceanic islands. A number of European and North American species are long-distance migrants; by contrast, the West and South African swallows are non-migratory. A few species of swallow and martin are threatened with extinction by human activities, although other species have benefited from human changes to the environment and live around humans. The swallows and martins have an evolutionary conservative body shape which is similar across the family but is unlike that of other passerines..
The swallows and martins have a worldwide cosmopolitan distribution, occurring on every continent except Antarctica. One species, the Pacific Swallow, occurs as a breeding bird on a number of oceanic islands in the Pacific Ocean, Swallows are excellent flyers, and use these skills to feed and attract a mate. Some species, like the Mangrove Swallow, are territorial, whereas others are not and simply defend their nesting site. In general, the males select a nest site, and then attract a female using song and flight, and (dependent on the species) guard their territory. The size of the territory varies depending on the species of swallow; in colonial-nesting species it tends to be small , but it may be much larger for solitary nesters. Outside of the breeding season some species may form large flocks, and species may also roost communally.