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The '''plain swift''' ('''''Apus unicolor''''') is a medium-sized [[Swift (bird)|swift]]. Although this [[bird]] is superficially similar to a [[barn swallow]] or [[Common house martin|house martin]], it is not related to those [[passerine]] species. The resemblances between the groups are due to [[convergent evolution]] reflecting similar life styles.
Swifts have very short legs that they use only for clinging to vertical surfaces. They never settle voluntarily on the ground, and spend most of their lives in the air, feeding on [[insect]]s that they catch in their beaks. They drink on the wing.
Plain swifts breed in colonies on cliffs, bridges and buildings on the [[Canary Islands]] and [[Madeira]], laying two eggs in a saucer-shaped nest made of flowerheads glued with saliva. They are partially [[bird migration|migratory]], with many birds leaving to winter in mainland [[Africa]]. Until recently it was thought that the birds wintered on the African coast but recent studies suggest they travel much further to the equatorial forests of Liberia and Guinea, a distance of 2,600 kilometres. Small numbers are also believed to breed in Morocco between Agadir and Essaouira, where a colony was found on coastal cliffs and possibly also in Mauritania where there are frequent sightings.<ref> Norton, T., Atkinson, P., Hewson, C. & Eduardo Garcia-del-Rey, E. 2018. [http://www.magornitho.org/2018/03/plain-swift-winter-west-africa/ Geolocator study reveals that Canarian Plain Swifts Apus unicolor winter in equatorial West Africa]. [https://africanbirdclub.org/sites/default/files/2013_Plain_Swift%20migration_Canary_Islands.pdf ''African Bird Club''] & ''Sociedad Ornitologica Canaria''. 15 pp</ref>
This 14–15 cm long species is very similar to the closely related [[common swift|common]] and [[pallid swift]]s, which also occur in the archipelagos, and separation is only possible with good views. Like its relatives, it has a short forked tail and very long swept-back wings that resemble a crescent or a [[boomerang]].
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