The plain swift (''Apus unicolor'') is a medium-sized

swift Swift or SWIFT most commonly refers to: * SWIFT, an international organization facilitating transactions between banks ** SWIFT code * Swift (programming language) * Swift (bird), a family of birds It may also refer to: Organizations * SWIF ...

. Although this

bird Birds are a group of warm-blooded vertebrates constituting the class (biology), class Aves (), characterised by feathers, toothless beaked jaws, the Oviparity, laying of Eggshell, hard-shelled eggs, a high Metabolism, metabolic rate, a fou ...

is superficially similar to a

barn swallow The barn swallow (''Hirundo rustica'') is the most widespread species of swallow in the world, occurring on all continents, with vagrants reported even in Antarctica. It is a distinctive passerine bird with blue upperparts and a long, deeply f ...

house martin ''Delichon'' is a small genus of passerine birds that belongs to the swallow family and contains four species called house martins. These are chunky, bull-headed and short-tailed birds, blackish-blue above with a contrasting white rump, and ...

, it is not related to those

passerine A passerine () is any bird of the order Passeriformes (; from Latin 'sparrow' and '-shaped') which includes more than half of all bird species. Sometimes known as perching birds, passerines generally have an anisodactyl arrangement of their ...

species. The resemblances between the groups are due to

convergent evolution Convergent evolution is the independent evolution of similar features in species of different periods or epochs in time. Convergent evolution creates analogous structures that have similar form or function but were not present in the last comm ...

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 Insects (from Latin ') are Hexapoda, hexapod invertebrates of the class (biology), class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (Insect morphology#Head, head, ...

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 The Canary Islands (; ) or Canaries are an archipelago in the Atlantic Ocean and the southernmost Autonomous communities of Spain, Autonomous Community of Spain. They are located in the northwest of Africa, with the closest point to the cont ...

and

Madeira Madeira ( ; ), officially the Autonomous Region of Madeira (), is an autonomous Regions of Portugal, autonomous region of Portugal. It is an archipelago situated in the North Atlantic Ocean, in the region of Macaronesia, just under north of ...

, laying two eggs in a saucer-shaped nest made of flowerheads glued with saliva. They are partially migratory, with many birds leaving to winter in mainland

Africa Africa is the world's second-largest and second-most populous continent after Asia. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 20% of Earth's land area and 6% of its total surfac ...

. 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. Norton, T., Atkinson, P., Hewson, C. & Eduardo Garcia-del-Rey, E. 2018
Geolocator study reveals that Canarian Plain Swifts Apus unicolor winter in equatorial West Africa''African Bird Club''
& ''Sociedad Ornitologica Canaria''. 15 pp This 14–15 cm long species is very similar to the closely related

common Common may refer to: As an Irish surname, it is anglicised from Irish Gaelic surname Ó Comáin. Places * Common, a townland in County Tyrone, Northern Ireland * Boston Common, a central public park in Boston, Massachusetts * Cambridge Com ...

and

pallid swift The pallid swift (''Apus pallidus'') is a Swift (bird), swift (order Apodiformes). Swifts have very short legs which they use only for clinging to vertical surfaces. The genus name ''Apus'' is Latin for a swift, thought by the ancients to be a ty ...

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 A boomerang () is a thrown tool typically constructed with airfoil sections and designed to spin about an axis perpendicular to the direction of its flight, designed to return to the thrower. The origin of the word is from Australian Aborigin ...

. It is entirely dark except for an indistinct pale throat patch. It is slimmer and more rakish than the pallid swift, and is darker than that species and lacks the obvious white throat. Distinguishing the plain swift from the similarly plumaged common swift is much more difficult, although juvenile common can be easily eliminated due to its white throat. The plain is slimmer and appears longer winged than the common, and has scaly underparts, difficult to see except with excellent views. The call is a loud dry scream similar to that of the common swift, though possibly higher pitched.

References

* ''Swifts'' by Chantler and Driessens,

External links

* Madeira Birds
Plain Swift
{{Taxonbar, from=Q1096617 Apus (genus) Birds of the Canary Islands Birds of Madeira Birds described in 1830 Taxa named by Sir William Jardine