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swallow: a small graceful songbird with long pointed wings, a notched or forked tail and rapid flight that migrates annually.

swallow

The bird family Hirundinidae is a group of passerines characterised by their adaptation to aerial feeding, and known as swallows and martins. The family comprises two subfamilies: Pseudochelidoninae (the river martins of the genus Pseudochelidon) and Hirundininae (all other swallows and martins). Within the Hirundiniae, 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.

Their adaptations to hunting insects on the wing are a slender streamlined body, and long pointed wings. Like the unrelated swifts and nightjars, which hunt in a similar way, they have short bills, but a wide gape.

The feet are designed for perching rather than walking, and the front toes are partially joined at the base. Many species have long tails.

Mud nests made by swallows.Swallows build their mud nests close to overhead shelter in locations that are protected from both the weather and predators. Many cave and cliff dweling species of swallow nest in large colonies. In historical times, the introduction of man-made stone structures such as barns and bridges has led to an abundace of colony sites around the globe, significantly increasing the bird's ranges during breeding season. Birds living in large colonies typically have to contend with both ectoparasites and conspecific nest parasitism. Old males benefit most from coloniality, since they are able to maintain their own nests and benefit from frequent extra-pair copulations.