Plain Swift (Apus unicolor)

A small swift measuring 14-15 cm in total length, with a wingspan of 38-39 cm. The plumage is mostly blackish-brown, with a pale throat—though not as white as that of the commons swift (Apus apus)—and the tail is forked. Its flight is fast and nimble, which is true of all swifts, and it has a distinguishing call. This species is endemic to the archipelagos of Madeira and the Canaries but has also been observed in the Savage Islands. It appears to breed on the Atlantic seaboard of Morocco, where it is a regular visitor in winter and spring, sometimes in significant numbers. It nests in the cracks and crevices of coastal cliffs, rocky islets, ravine walls, inland crags, buildings and bridges, up to 2,000 m above sea level. The breeding season extends from March to September, but may begin earlier in the eastern Canary Islands. A clutch of 1-2 eggs is laid in a cup-shaped nest, lined with feathers cemented together with its own saliva. It can produce two or three annual broods. Its diet is exclusively insectivore; hunting can take place at night, particularly near lights and street-lamps. It also gathers in large flocks of up to 200 specimens that feed copiously in open terrain. A partly migratory bird, it leaves the islands between September and October, to return in mid-winter and early spring. Its wintering sites are unknown, but several individuals frequent the Atlantic seaboard of Morocco and there have also been observations in Mauritania and Cape Verde. It remains in certain parts of the Canaries all year round, for example in Santa Cruz de Tenerife. The swift is a common bird and gathers in large breeding colonies, but several factors have or could have a negative impact, including chemical products used in agriculture, roadkill, collisions with overhead cables, leisure activities that affect breeding and the destruction of breeding colonies located in buildings.